No funky background music, no constant talking, just pure engineering, you dont need much else do you, just the right amount of narration to explain things then let the viewer enjoy, brilliant episode again 👍
One year on from this episode release it’s now my turn to overhaul my rear booster. What an episode and so thankful that you created this one. Top job Jethro
This is the most enjoyable channel i've ever seen. The calmness, precision and good tips relax me like no other. Amazing work, keep cool ! best regards from Hungary :)
thanks for your video. I have a alfa spider with twin boosters and wondered what they did. thank you for explaining and showing how it works. The video was great in understanding how it works. thanks for taking the time to explain
@@JethroBronner Whilst watching this video, part of my brain was occupied thinking how fear can stem from ignorance. You have explained this repair wonderfully and it is always such a pleasure to view your work. I am sure that many of your viewers will feel the same as I. Brake boosters demystified in one easy lesson! Thanks Jethro, you are a Star mate!
Hello, I have a Hillman Hunter 77 with this brake system and with this video I just understood how the remote brake works. Thank you very much and greetings from Perú
Jethro that was a master class on rebuilding and restoring a brake booster. I doubt I could keep all the parts in order, but I'm glad that you can! Always a pleasure to stop by and see what you are up to!
That's why we should have explosion drawings for these multi-part devices, best with old stock numbers pointing at each part, too, to be able gooogling numbers instead of pics ......
9:25 - I had to re-watch the explanation of how a vacuum booster works - not because it wasn't clear, but because I was distracted by wondering "Is that a Montblanc 145 in burgundy?"...
Thanks so much for making this video. I’ve just watched it for a second time and used it as a guide while rebuilding both the boosters on my ‘73 Super. One of the little air valves was really stuck but I read online that if you blanked off the end of the cylinder you could pump it full of grease to push the piston out. It worked a treat!
You’re either born engineer or a born producer, I’m not sure which, but your videos are always educational, soothing and make me want to restore cars to the end of my days. 👍
Only perfection is good enough for Jethro, another piece of art! Good luck with your business, and remember we all watch the other cartubers too, so a little less perfection is good enough for is 2. Not that i don't appreciate your hard work, but you gotta watch yourself sometimes. Best of luck
Just rewatched this as I reassembled the first of my two boosters. So useful to double check the order and orientation of all of the parts. Such an informative video. Thanks so much Jethro!
If only things still were made to be this serviceable. I had never given much though before on how a booster really works, but I think I understand it now. Quite interesting and well put together!
I've always looked at brake boosters as a monolithic unserviceable lump, and in some cars they are. This was quite educational, I've never seen one with a removeable band.
Even the ones with bent tin to keep everything together are repairable/rebuildable. Learnt that in Middle East where my T1N 212 Sprinter had a total booster failure: the fixer got it bent open, cut a new diaphragm out of plain rubber and put it back together. I still drive with it confidently 10 years after, even with a low km parts-car spare in the cellar meanwhile. Never touch a working system, and repair the non-working ones properly once need be. I gotta learn to metal-plate like Jethro does it - these Mercedes Boosters are black matte on bare steel and turn into crumbly brownish once You spill a first drop of brake fluid on those.
@@manfredschmalbach9023 We've all had to do emergency repairs, and that sounds like the guy knew what he was doing. My best effort was fixing a broken heater hose stub by jamming a cork in it. I managed to get to a tiny town, asked for a cork at the local general store and borrowed a knife to pare it into shape. It was still there when I sold the car - a Ford ZD Fairlane - to my cousin two years later.
@@shedtime_au Have a friend with a heavily changed, even more used Yamaha 650 XS; she's third owner and the thing meanwhile has unbelievable 470 k km - she got it with 50 tkm in its fourth year 1979 from the second owner, changed it to her liking from ape-hanger to step-seat to better brakes to whatever else plus a Leopard paint she did herself (artsy painter, airbrush artist and hyperrealism-airbrusher beneath 12 other artsy fartsy skillz ...) and has used it ever since - wasn't even unregistered for a winter in 43 years. We were on a tour somewhere in Syria back in the days while it still was an adventure and not yet idiocy when her rev meter shaft-inlet (engine side) broke off - there's oil behind it, and it started spilling. She stopped it with her thumb, burnt herself good, grabbed a couple pine branch stumps in a hurry, the only thing resembling a cork or filler piece within her reach with the thumb on the leak, tried some of 'em and put the one in that fitted best. We cut the excess with a swiss knife's saw after it swelled absolutely tight. That was 1993 or so ... since then, the engine was opened once and bigger pistons with new rings were put in after honing, and some minor other stuff, the deleted starter motor was put in again for her sixtieth birthday and shit like that - the pine bung still is in there, she says she feels her engine and does not need a rev counter, she had in the bum .... The emergency compromise usually is the longest lasting solution.
Excellent video, highest quality technical content and taking the angst-loaden mystery out of the brake-black-box. I really enjoy Your calm, music-, fake-suspension- and drama-free tech vids very much. I gotta learn how to metal-plate like You do it - that quality surface is way over any three layer paint "restoration" I ever tried with the outsides of crumbly-brownish booster housings. Thanks for sharing!
fantastic episode and like others comments i love the fact you dont have rave music playing all the way through. its so relaxing watching you and i love that you can hear your spanners clanking as you work .. awesome cant wait for the next .. respect from the uk
Just watched a '67 Duetto Spider auctioned off online. It went for AU56,000 which, considering it was in fairly average condition, was a bit of an eye-opener. Oh, and you've inspired this old Alfa fanatic to re-enter the fray. Later this week I'll be taking delivery of a 2003 147 Ti 5-speed. It's not as cool as a Duetto but I'm a pensioner, so have to work with what I can afford. It has 88,600km on the clock and needs a crank sensor, an alternator, a cambelt set (7 years!) and some serious clearcoat correction. But at AU$2,200 I just couldn't pass it up.
Thank you very much for your video, I've been waiting for it for a long time. It's the only video on the internet that explains how to reconstruct a bonaldi, fantastic!
Clear and professional work as usual, I really enjoyed watching your video, useful tips and extreme precision in the cleaning and reassembling parts. I will wait for the next episode to learn something new. Thanks for your videos.
Nicely done Jethro. At least its serviceable, most brake boosters are a sealed unserviceable unit and I would imagine that a replacement unit for this car would be unobtanium.
Just got around to watching this one. It appears to be what we in America call a "hydrovac" booster, actuated by hydraulic pressure instead of just a pushrod from the pedal. There is one on my 1962 Ford F-600 truck project! I sent mine out to be restored. it was worth $400 to save me time hunting for parts! I made a video on the history and basic operation of the unit over on my other channel Duluth Junction Workshop. Over here they were most common on medium duty commercial trucks as well as luxury cars, so it's very interesting to see the same setup on a sports car! I have to imagine they had to use a hydrovac due to space limitations. Cheers!
Perfect timing Jethro, I have just stripped both of the boosters for my 1973 2000 GTV and am about to clean and reassemble them. Thanks for the video! I have the rebuild kits from Classic Alfa - when I bought those in 2019 they were also available from Highwood and Alfastop. They include the diaphragm, seals, gaskets, bolt lock plates and the 90 deg hose. 15+ years ago I had both sleeved in stainless but one diaphragm had now split and both boosters were leaking slightly into the vacuum chamber. There was quite a lot of crystalized brake fluid in the air valve. I have also just rebuilt the double circuit master cylinder, honed with a new set of seals. My fingers will be well crossed when I put it all back together again :) Early in my ownership of the car I had trouble with the rear brakes being slow to release, which turned out to be the small 90 degree rubber hose collapsing under vacuum. Took a while to find!
@@JethroBronner yep, bleeding can be a hassle with this version of the system. I have found that it helps to do a final bleed with the engine running so that the boosters are operating. I also added "speedbleeder" non-return nipples to the calipers, which made it a lot easier with one person. I will be interested to seeing how the bleed process goes with everything I'm replacing now...
@@markbattley8515 I have a 1977 UK RHD 2000 Spider, with all the joys of dual circuit brakes including twin Bonaldi brake servos. I pressure bleed through the brake reservoir cap but limit the pressure to around 12 psi which works for me. A word of warning if you use this method the flexible feed pipes from the bottom of the reservoir to the rigid brake pipes must be secured with good quality stainless steel hose clips- a lesson I learnt nearly 34 years ago now!
Jethro.... good to see you today.. this booster tutorial was excellent. I learned a few thing today... Not sure the Alfa hand book went to that extent on the subject....very nice..
@@JethroBronner These boosters were after-market parts fitted by dealers, right? So, Alfa wasn't even supposed to take these into their manuals I reckon. I had a couple Bertones back in the days (LHD though, obviously, as a Bavarian😁) and all came from Italy without boosters. Otherwise I found Alfa manuals pretty usable compared to Fiat or Peugeot manuals. Cheers!
Brake fluid being drawn into an engine (in small quantities) isn't a horrible thing. Many, many moons ago, my high school physics teacher owned a car repair shop. I was having trouble with carbon build-up on the valves, so he showed me how to mix up a 50/50 mixture of brake fluid and auto transmission fluid and poured down the carbs- it really cleaned up the cylinders!
@23:57 - It was not mention but I feel I should state it here for everyone's benefit. There is a difference between a vacuum hose and a regular PCV hose. A vacuum hose is designed and reinforced in such a manner that the hose stays rigid and does not collapse under a vacuum. Although, the performance of the PCV hose might be satisfactory now. You may want to reconsider your choice for long term reliability and safety. Think about the condition and environment the hose will have to endure. The prolong exposure of high temperature will make the hose soft and supple and under the right circumstances the hose may collapse, leading to unsafe brake operation.
@@JethroBronner good thing they are cheap. But yeah, it's crazy like service manuals used to show how to set up ignition timing and replace crankshaft bearings and now it's all "please go to authorised service".
Fantastic work as always! Reassembly of the main unit rubber seal looked like a tedious task with a spring constantly fighting against you and a a shaft to line up...and a clamp to try slip on 😬
Jethro .. that’s a perfect rendition of how it’s done.. well executed.! The best bit was the leopard scarf rag.. too good to use , I would have been wearing it hehe.. Love to see your plating process...
Alfas are the only cars I've ever heard of to have problems with vacuum brake boosters, at least as catastrophic as sucking brake fluid into cylinders :D
@@JethroBronner most old ones i’ve seen had them separate. 1960’ fiat 124 had a brake master cylinder bolt on to the booster. With it being a self contained unit operated by vaccum that just increases force on the pushrod
@@MrDoroh The Fiat 124 Coupe used a different brand of booster called Beditalia which I assume was made by Bendix in Italy. As you say ,the booster was attached to the end of the master cylinder. The later 105 Alfas from 1970 onwards had the same system as the Fiat 124, because by then Alfa had ditched the floor mounted pedals and mounted the pedals from the top . Right hand drive 105 cars kept the floor mounted pedals, so it was not possible to mount the booster at the end of the master cylinder.
@@EliteRock Yes it was hilarious to see the look of bafflement of the not so experienced mechanics, but the good mechanics always checked the vacuum line from the cylinder head to the brake booster, brake fluid there meant the engine was burning brake fluid, hence the white smoke
On top of all right comments: did everyone notice the good taste "touch" of using a fontain pen to mark the lines of all those small parts, certainly a "Montblanc"? Justy amazing how Jethro is able to turns engineering into art!
During my college days in the mid 1970’s I bought a used 1969 Duetto Spyder. Correct me if I am wrong but I believe it had 2 Bonaldi boosters. Both leaked, constant spongy pedal and no one could repair it. Ended up removing the boosters and the pedal was finally firm but needed muscular legs to stop. Very dangerous. ATE calipers all around. Too bad I didn’t have access to your knowledge. The zinc plating looks very good, should have given it a dichromate dip for corrosion protection.
Yes the later 1750/2000 cars had duel circuit brakes, and had duel boosters. I'm very new to doing electroplating, so I'll look into that for my next batch, thank you!
you could probably manufacture a somewhat decent filter from an air silencer for pneumatic cylinders, by the lloks of it a 1/4'' cylinder silencer would do
My '67 Duetto did not have the booster. The big problem I ran into is the calipers were aluminum with chrome plated piston bores, and could not be just simply re-built if corroded. Once I got good calipers, the brakes were very good.
@@JethroBronner Renault used to use alloy calipers - I was surprised to find them on the front of a 1976 12 (not a Gordini or anything like that) I once owned. Under-rated/under-appreciated cars BTW.
Hi Jethro, I find your movies both entertaining and informative, thank you. However there is one area that I can't find anywhere and that is a repair of a 116 rear caliper. I know you specialise in 105's however can you give this a thought as no one else seems to want to cover this topic. Regards. Jim
Hello Jethro, really nice job on your Duetto. Your videos are so helpful for my restoration. As i watched this video I mentioned that on mine air valve the small spring is missing😢... obviously someone disabled in the past and lost this spring 😢. Could you give me some information of this particular spring? Greetings from Austria. Fabio
I think your 911 probably had the larger version used on the 1750/2000 GTVs. Ferrari 308s also used them but with a spacer between the two halves, for widened, vented discs.
I wonder if I'm right in thinking these are a "remote" type of booster? That is to say it is not physically connected to the brake master cylinder actuated by the driver. You normally see the booster located on the same side of the car as the driver adjacent to the bulkhead but not in this case. The early Ford Escort Mexicos and RS1600's had a remote brake booster made by Girling which were a nightmare to rebuild even in the 80's when parts were available off the shelf. Instead of being physically actuated by the brake pedal they are actuated by vacuum which adds a another bunch of seals and pipes and valve which can go wrong.
Yup this is the remote type of booster. The later LHD Alfas had boosters incorporated into the brake master cylinder, but that won't work on RHD cars, as there is not space on the right side of the engine bay, so they had to use remote boosters.
Hi Jethro! I join the complements for the excellent work you did in this video! I have a technical question for you, if you're so kind to help me. Is the spring you put on at 20:35 the one from the previous brake booster? I saw that the spring is not included in the repair kit (neither yours nor mine). Since I lost the old one, could you by any chance tell me the measurements of the spring you have so that I could get it somehow? Thank you very much!
Hey Jethro you say very simple 🤣 but where did you find the explanation about how this booster works ? so good video again ... for a little bit more i would think i could do it myself 🤣🤣🤣
When I started rebuilding these I just took one apart to see how it worked, It's pretty self explanatory if you can follow the path of air and brake fluid in your head.
Great video, thank you, and great channel too!. I finally fixed an old "juddery" brake problem on a 1966 GTV by rebuilding the servo/booster this year. But...like you, I had a broken red plastic spring perch, so had to re-assemble with the remnants... Could you let me know if/where you managed to buy that white one - thanks!
The white one came from my spares, I have a few boosters in parts that I keep around for this sort of thing. Whenever I see people selling Alfa parts I try buy old boosters.
As always simply fantastic. We all love your work. I don't have a deep stash of parts to pull spares from. What sources for booster parts do you know of. Is there a Bondi specialist supplier of components you know of or is there a kit from Classic Alfa or another supplier/ Thanks as always
For new service parts Classic Alfa carries what you'll usually need, and new boosters if you really can't repair an old one, I've linked their parts in the description of the video.
I enjoyed that, although the lack of a kit of new parts always makes me very uneasy. I guess if the Cubans can manage, so can we! A couple of things I wonder about, though. It's been my understanding that brake fluid protects rubber rather than harming it. Also, if that was red Loctite, why? Last I bought it, it was labeled permanent, although very high heat could burn it away and allow bolts to be loosened but that's not the intended use. Blue is guaranteed to lock parts until you take a wrench to the fastener.
No funky background music, no constant talking, just pure engineering, you dont need much else do you, just the right amount of narration to explain things then let the viewer enjoy, brilliant episode again 👍
Thank you!
100% right.
Nothing to add. Perfect classics mech entertainment. Thank you.
Exactly what I thought. An immaculate job and presentation.
One year on from this episode release it’s now my turn to overhaul my rear booster. What an episode and so thankful that you created this one. Top job Jethro
This is the most enjoyable channel i've ever seen. The calmness, precision and good tips relax me like no other. Amazing work, keep cool ! best regards from Hungary :)
Wow, thank you! That's very kind!
ridiculous that this channel is only 42k subs considering how incredibly well produced it is. amazing work
That’s very kind of you to say, hopefully with more regular and consistent uploads I’ll get there.
Thanks again for your great videos
Glad you like them! Thanks for watching!
thanks for your video. I have a alfa spider with twin boosters and wondered what they did. thank you for explaining and showing how it works. The video was great in understanding how it works. thanks for taking the time to explain
Whooo Hooo! Made my day Jethro!
Thanks! Glad you're back to watch this one
@@JethroBronner Whilst watching this video, part of my brain was occupied thinking how fear can stem from ignorance.
You have explained this repair wonderfully and it is always such a pleasure to view your work.
I am sure that many of your viewers will feel the same as I. Brake boosters demystified in one easy lesson!
Thanks Jethro, you are a Star mate!
Excellent video, like the rest of them.
Great to see the passion you also share for these amazing pieces of mobile art.🤟🏻😎
Thank you very much!
Easy to see why no one wants to touch these. Another area of expertise you've tackled, Jethro. Kudos!
Hello, I have a Hillman Hunter 77 with this brake system and with this video I just understood how the remote brake works. Thank you very much and greetings from Perú
Lovely video, as always!
Thanks Matteo!
You have a really lovely Duetto Spider. I owned a 1600 GT Junior back in 1986 so I know how special these cars are... 👍
Thank you! But this isn't my car, it belongs to a friend of mine.
Jethro that was a master class on rebuilding and restoring a brake booster. I doubt I could keep all the parts in order, but I'm glad that you can! Always a pleasure to stop by and see what you are up to!
Thanks! Yeah the first time I took one of these apart I found it pretty tough to keep all the parts orderly.
That's why we should have explosion drawings for these multi-part devices, best with old stock numbers pointing at each part, too, to be able gooogling numbers instead of pics ......
Photo cameras in phones can be of help. Of course, using them consistently... Is another form of discipline to be acquired.
Just a quick note to say hi, and feed the algorithm. Excellent video as always!
Awesome, thank you!
I can’t add anything that hasn’t already been said. Great work as usual. Thanks!
I appreciate that!
Jethro great job.I did this brake booster bonaldi on gt junior few years ago.buon lavoro bests regards from slovakia👌
Thanks! 👍
i love the jazz background! Really suits the car
I'm definitely in a modern jazz phase with the channel
9:25 - I had to re-watch the explanation of how a vacuum booster works - not because it wasn't clear, but because I was distracted by wondering "Is that a Montblanc 145 in burgundy?"...
Yes it is!
i swear you are the only guy on this planet that can make me watch brake booster repair
Thanks so much for making this video. I’ve just watched it for a second time and used it as a guide while rebuilding both the boosters on my ‘73 Super. One of the little air valves was really stuck but I read online that if you blanked off the end of the cylinder you could pump it full of grease to push the piston out. It worked a treat!
Always enjoyable to watch your “clean” video..
You’re either born engineer or a born producer, I’m not sure which, but your videos are always educational, soothing and make me want to restore cars to the end of my days. 👍
Really nice.... Some things strangely falls into a category of "unserviceable"... I really like it when that is proven wrong.. :)
Thanks a million for the non-stop detail your videos convey.
My pleasure!
I added some tipps & tricks. 40 Years in the hobby. See below. Great video, great work. Cheers.
Immensely satisfying. Not only that: no copper grease on my hands! Great video. :)
Glad you enjoyed it!
Great video, would love to see your cleaning and plating process.
Yes let’s see it please 👨🏫
This was my first ever attempt at electroplating, so I will need to get it a lot smoother before I film it haha
Bravo, nice video. You removed the mystery of these things.
Wow what great blog 👌👍🏼
Thank you!
Good Job: Clear explanation and good photography. Thank you!
Someone in Italy did just that 50-ish years ago when the unit was first assembled. Good viewing, thanks.
Great information and filming.
Thank you!
Only perfection is good enough for Jethro, another piece of art!
Good luck with your business, and remember we all watch the other cartubers too, so a little less perfection is good enough for is 2. Not that i don't appreciate your hard work, but you gotta watch yourself sometimes. Best of luck
Fascinating content as always 👍🇿🇦
Glad you enjoyed it
Time for the next episode
Just fabulous craftsmanship brilliant content Jethro 🥳👍
Thank you!
Precision work as usual. Meticulous. I really enjoy your attention to detail.
Thank you very much!
Hey Jethro, that was superb and so relaxing to watch. I love rebuilding parts on old cars and bikes, so satisfying. Top work Sir!. 👍
Thanks 👍
the perfect instructional video!! thank you I m about to rebuild the 2 boosters in my Lotus Europa (Lockheed brand but very similar I guess)
All I can say is, I'm impressed by your videos. My 69 Berlina has two boosters (South Africa)
Nice job! Nice result!
Thank you!
Just rewatched this as I reassembled the first of my two boosters. So useful to double check the order and orientation of all of the parts. Such an informative video. Thanks so much Jethro!
Whow, amazing again! My Julia needs some help at the same breakpart.
Your video took away my fear of being overtaken a bit.
Thank you for that!
I'm glad this video is useful!
If only things still were made to be this serviceable. I had never given much though before on how a booster really works, but I think I understand it now. Quite interesting and well put together!
Yes it's a shame that things are no longer built to be repaired, but only replaced.
I've always looked at brake boosters as a monolithic unserviceable lump, and in some cars they are. This was quite educational, I've never seen one with a removeable band.
I used to feel that way too
Even the ones with bent tin to keep everything together are repairable/rebuildable. Learnt that in Middle East where my T1N 212 Sprinter had a total booster failure: the fixer got it bent open, cut a new diaphragm out of plain rubber and put it back together. I still drive with it confidently 10 years after, even with a low km parts-car spare in the cellar meanwhile.
Never touch a working system, and repair the non-working ones properly once need be.
I gotta learn to metal-plate like Jethro does it - these Mercedes Boosters are black matte on bare steel and turn into crumbly brownish once You spill a first drop of brake fluid on those.
@@manfredschmalbach9023 We've all had to do emergency repairs, and that sounds like the guy knew what he was doing. My best effort was fixing a broken heater hose stub by jamming a cork in it. I managed to get to a tiny town, asked for a cork at the local general store and borrowed a knife to pare it into shape. It was still there when I sold the car - a Ford ZD Fairlane - to my cousin two years later.
@@shedtime_au Have a friend with a heavily changed, even more used Yamaha 650 XS;
she's third owner and the thing meanwhile has unbelievable 470 k km - she got it with 50 tkm in its fourth year 1979 from the second owner, changed it to her liking from ape-hanger to step-seat to better brakes to whatever else plus a Leopard paint she did herself (artsy painter, airbrush artist and hyperrealism-airbrusher beneath 12 other artsy fartsy skillz ...) and has used it ever since - wasn't even unregistered for a winter in 43 years. We were on a tour somewhere in Syria back in the days while it still was an adventure and not yet idiocy when her rev meter shaft-inlet (engine side) broke off - there's oil behind it, and it started spilling. She stopped it with her thumb, burnt herself good, grabbed a couple pine branch stumps in a hurry, the only thing resembling a cork or filler piece within her reach with the thumb on the leak, tried some of 'em and put the one in that fitted best. We cut the excess with a swiss knife's saw after it swelled absolutely tight. That was 1993 or so ... since then, the engine was opened once and bigger pistons with new rings were put in after honing, and some minor other stuff, the deleted starter motor was put in again for her sixtieth birthday and shit like that - the pine bung still is in there, she says she feels her engine and does not need a rev counter, she had in the bum .... The emergency compromise usually is the longest lasting solution.
@@manfredschmalbach9023 I like this story. :-)
Fantastic ep, J. Demystifying but in a real easy to follow way. Much appreciated.
Perfect job , bravo !
Thank you!
Excellent video, highest quality technical content and taking the angst-loaden mystery out of the brake-black-box.
I really enjoy Your calm, music-, fake-suspension- and drama-free tech vids very much. I gotta learn how to metal-plate like You do it - that quality surface is way over any three layer paint "restoration" I ever tried with the outsides of crumbly-brownish booster housings. Thanks for sharing!
fantastic episode and like others comments i love the fact you dont have rave music playing all the way through. its so relaxing watching you and i love that you can hear your spanners clanking as you work .. awesome cant wait for the next .. respect from the uk
That's very kind of you to say! Thank you!
Just watched a '67 Duetto Spider auctioned off online. It went for AU56,000 which, considering it was in fairly average condition, was a bit of an eye-opener.
Oh, and you've inspired this old Alfa fanatic to re-enter the fray. Later this week I'll be taking delivery of a 2003 147 Ti 5-speed. It's not as cool as a Duetto but I'm a pensioner, so have to work with what I can afford. It has 88,600km on the clock and needs a crank sensor, an alternator, a cambelt set (7 years!) and some serious clearcoat correction. But at AU$2,200 I just couldn't pass it up.
I’m always amazed at all the parts that you manage to rebuild. Great work as usual 👍
Thank you very much!
nice, they look similar to the VH44 brake booster
Thank you very much for your video, I've been waiting for it for a long time. It's the only video on the internet that explains how to reconstruct a bonaldi, fantastic!
Glad it was helpful!
Very nice and detailed video, thx!
Glad you enjoyed it!
Clear and professional work as usual, I really enjoyed watching your video, useful tips and extreme precision in the cleaning and reassembling parts. I will wait for the next episode to learn something new. Thanks for your videos.
Nicely done Jethro. At least its serviceable, most brake boosters are a sealed unserviceable unit and I would imagine that a replacement unit for this car would be unobtanium.
They're actually not too difficult to get new, but they are just a lot of money.
Just got around to watching this one. It appears to be what we in America call a "hydrovac" booster, actuated by hydraulic pressure instead of just a pushrod from the pedal. There is one on my 1962 Ford F-600 truck project! I sent mine out to be restored. it was worth $400 to save me time hunting for parts! I made a video on the history and basic operation of the unit over on my other channel Duluth Junction Workshop. Over here they were most common on medium duty commercial trucks as well as luxury cars, so it's very interesting to see the same setup on a sports car! I have to imagine they had to use a hydrovac due to space limitations. Cheers!
Great video
Thanks!
Perfect timing Jethro, I have just stripped both of the boosters for my 1973 2000 GTV and am about to clean and reassemble them. Thanks for the video! I have the rebuild kits from Classic Alfa - when I bought those in 2019 they were also available from Highwood and Alfastop. They include the diaphragm, seals, gaskets, bolt lock plates and the 90 deg hose. 15+ years ago I had both sleeved in stainless but one diaphragm had now split and both boosters were leaking slightly into the vacuum chamber. There was quite a lot of crystalized brake fluid in the air valve. I have also just rebuilt the double circuit master cylinder, honed with a new set of seals. My fingers will be well crossed when I put it all back together again :) Early in my ownership of the car I had trouble with the rear brakes being slow to release, which turned out to be the small 90 degree rubber hose collapsing under vacuum. Took a while to find!
Oh yeah the dual circuit master cylinders can be very tricky to get right, and bleeding them isn't easy either.
@@JethroBronner yep, bleeding can be a hassle with this version of the system. I have found that it helps to do a final bleed with the engine running so that the boosters are operating. I also added "speedbleeder" non-return nipples to the calipers, which made it a lot easier with one person. I will be interested to seeing how the bleed process goes with everything I'm replacing now...
@@markbattley8515 I have a 1977 UK RHD 2000 Spider, with all the joys of dual circuit brakes including twin Bonaldi brake servos. I pressure bleed through the brake reservoir cap but limit the pressure to around 12 psi which works for me. A word of warning if you use this method the flexible feed pipes from the bottom of the reservoir to the rigid brake pipes must be secured with good quality stainless steel hose clips- a lesson I learnt nearly 34 years ago now!
Great video, thanks so much
Glad you liked it!
Jethro.... good to see you today.. this booster tutorial was excellent. I learned a few thing today... Not sure the Alfa hand book went to that extent on the subject....very nice..
Thanks! Yeah there's actually nothing in the available workshop manuals about boosters.
@@JethroBronner These boosters were after-market parts fitted by dealers, right? So, Alfa wasn't even supposed to take these into their manuals I reckon. I had a couple Bertones back in the days (LHD though, obviously, as a Bavarian😁) and all came from Italy without boosters. Otherwise I found Alfa manuals pretty usable compared to Fiat or Peugeot manuals. Cheers!
Top quality content, enjoyed every second of this video!
Glad you enjoyed it!
Maybe alfa part supplier's should sponsor you for instruction video's, well done.
I've actually recently made a deal with Classic Alfa, and I'll be using their parts in some upcoming projects.
Brake fluid being drawn into an engine (in small quantities) isn't a horrible thing. Many, many moons ago, my high school physics teacher owned a car repair shop. I was having trouble with carbon build-up on the valves, so he showed me how to mix up a 50/50 mixture of brake fluid and auto transmission fluid and poured down the carbs- it really cleaned up the cylinders!
Quality content done with style! Nice work JB!
Thank you!
Such peerless work, and I always celebrate when you release a new video! Spectacular filming, and great voice-over. Thanks for this!
After my 5th or 6th booster on my '65 it was nice to see just how simple of a part has given me so many headaches! Great video, Jethro.
@23:57 - It was not mention but I feel I should state it here for everyone's benefit. There is a difference between a vacuum hose and a regular PCV hose. A vacuum hose is designed and reinforced in such a manner that the hose stays rigid and does not collapse under a vacuum. Although, the performance of the PCV hose might be satisfactory now. You may want to reconsider your choice for long term reliability and safety. Think about the condition and environment the hose will have to endure. The prolong exposure of high temperature will make the hose soft and supple and under the right circumstances the hose may collapse, leading to unsafe brake operation.
Thanks
You're most welcome!
It's great that they are user serviceable. ATE in my Saab 96 is factory sealed
Ah well that's a pain. I really like how everything in the 1960s was built to be serviceable, unlike how things are now.
@@JethroBronner good thing they are cheap. But yeah, it's crazy like service manuals used to show how to set up ignition timing and replace crankshaft bearings and now it's all "please go to authorised service".
@@autka_me yes and “do not drink contents of battery”
Fantastic Jethro! Thank you.
Much awaited and appreciated, fine filming and engineering as always.
Thanks 👌
Glad you enjoyed it
Great video Jethro!
Excellent
Good work ❤
Fantastic work as always! Reassembly of the main unit rubber seal looked like a tedious task with a spring constantly fighting against you and a a shaft to line up...and a clamp to try slip on 😬
Yeah that requires some wrestling to get it together, if you let go it will shoot parts across the workshop.
a great video like always :-)
Thank you!
Wow you have know idea how much this helps me 😀 Thank you very much for a great tutorial, and yes you explained it perfectly
You're very welcome! Thank you!
Jethro .. that’s a perfect rendition of how it’s done.. well executed.!
The best bit was the leopard scarf rag.. too good to use , I would have been wearing it hehe..
Love to see your plating process...
I feel like..I should drink coffee while watching ..
I’d recommend it ☕️👍
Alfas are the only cars I've ever heard of to have problems with vacuum brake boosters, at least as catastrophic as sucking brake fluid into cylinders :D
I imagine anything with a vacuum booster could end up with fluid in the intakes if the seals leak.
I was pretty common with all of them back in the day, some makes more than others. Many an owner/home mechanic baffled by a smoking exhaust.
@@JethroBronner most old ones i’ve seen had them separate. 1960’ fiat 124 had a brake master cylinder bolt on to the booster. With it being a self contained unit operated by vaccum that just increases force on the pushrod
@@MrDoroh The Fiat 124 Coupe used a different brand of booster called Beditalia which I assume was made by Bendix in Italy. As you say ,the booster was attached to the end of the master cylinder. The later 105 Alfas from 1970 onwards had the same system as the Fiat 124, because by then Alfa had ditched the floor mounted pedals and mounted the pedals from the top . Right hand drive 105 cars kept the floor mounted pedals, so it was not possible to mount the booster at the end of the master cylinder.
@@EliteRock Yes it was hilarious to see the look of bafflement of the not so experienced mechanics, but the good mechanics always checked the vacuum line from the cylinder head to the brake booster, brake fluid there meant the engine was burning brake fluid, hence the white smoke
Excellent, thorough workmanship and very satisfying to watch and listen to. Would it be possible ti take a 5 minute time out to show us your watches?
Maybe at some point I'll do a video about my watches, but there are only 2 of them.
Perhaps a it of lapping, on the end of the rod that fits into the high pressure piston? Just an idea...
Yeah that's a good idea, especially with one that's been refaced.
On top of all right comments: did everyone notice the good taste "touch" of using a fontain pen to mark the lines of all those small parts, certainly a "Montblanc"?
Justy amazing how Jethro is able to turns engineering into art!
Thank you! Yes it's a 145, which was a gift from a dear friend.
Of course - could You _not_ notice something like that?
I did notice the MB pen too :D
Electro plating instruction would be a very interesting video.
I’m really not in any position to be showing anyone else how to electroplate, I’m very new to it
@@JethroBronner I understand I like restoring old BMW motorcycles and it would be a great skill to possess thanks
During my college days in the mid 1970’s I bought a used 1969 Duetto Spyder. Correct me if I am wrong but I believe it had 2 Bonaldi boosters. Both leaked, constant spongy pedal and no one could repair it. Ended up removing the boosters and the pedal was finally firm but needed muscular legs to stop. Very dangerous. ATE calipers all around. Too bad I didn’t have access to your knowledge. The zinc plating looks very good, should have given it a dichromate dip for corrosion protection.
Yes the later 1750/2000 cars had duel circuit brakes, and had duel boosters. I'm very new to doing electroplating, so I'll look into that for my next batch, thank you!
JB, the hottest auto vlogger on TH-cam by far!!!!!!
you could probably manufacture a somewhat decent filter from an air silencer for pneumatic cylinders, by the lloks of it a 1/4'' cylinder silencer would do
My '67 Duetto did not have the booster. The big problem I ran into is the calipers were aluminum with chrome plated piston bores, and could not be just simply re-built if corroded. Once I got good calipers, the brakes were very good.
Aluminium callipers? Maybe it was optioned with GTA callipers? That would be a rare and expensive set of callipers.
@@JethroBronner Renault used to use alloy calipers - I was surprised to find them on the front of a 1976 12 (not a Gordini or anything like that) I once owned. Under-rated/under-appreciated cars BTW.
Nice job. Is there an overhaul kit where all the new gaskets are present? If so, can you pass me the purchase link? Thank you
Hi Jethro, I find your movies both entertaining and informative, thank you. However there is one area that I can't find anywhere and that is a repair of a 116 rear caliper. I know you specialise in 105's however can you give this a thought as no one else seems to want to cover this topic. Regards. Jim
Hello Jethro,
really nice job on your Duetto.
Your videos are so helpful for my restoration.
As i watched this video I mentioned that on mine air valve the small spring is missing😢... obviously someone disabled in the past and lost this spring 😢.
Could you give me some information of this particular spring?
Greetings from Austria.
Fabio
I think my ‘73 Porsche 911 used the same brake calipers. Do not remember if they had a booster they called them “A” caliper’s the A from Alfa.
I think your 911 probably had the larger version used on the 1750/2000 GTVs. Ferrari 308s also used them but with a spacer between the two halves, for widened, vented discs.
I wonder if I'm right in thinking these are a "remote" type of booster? That is to say it is not physically connected to the brake master cylinder actuated by the driver. You normally see the booster located on the same side of the car as the driver adjacent to the bulkhead but not in this case. The early Ford Escort Mexicos and RS1600's had a remote brake booster made by Girling which were a nightmare to rebuild even in the 80's when parts were available off the shelf. Instead of being physically actuated by the brake pedal they are actuated by vacuum which adds a another bunch of seals and pipes and valve which can go wrong.
Yup this is the remote type of booster. The later LHD Alfas had boosters incorporated into the brake master cylinder, but that won't work on RHD cars, as there is not space on the right side of the engine bay, so they had to use remote boosters.
Hi Jethro! I join the complements for the excellent work you did in this video! I have a technical question for you, if you're so kind to help me. Is the spring you put on at 20:35 the one from the previous brake booster? I saw that the spring is not included in the repair kit (neither yours nor mine). Since I lost the old one, could you by any chance tell me the measurements of the spring you have so that I could get it somehow? Thank you very much!
Whoa.... Do you have the brakes wrapped up and driving it ? We sure would like to hear about that 😎
Hey Jethro you say very simple 🤣 but where did you find the explanation about how this booster works ?
so good video again ...
for a little bit more i would think i could do it myself 🤣🤣🤣
When I started rebuilding these I just took one apart to see how it worked, It's pretty self explanatory if you can follow the path of air and brake fluid in your head.
Great video, thank you, and great channel too!. I finally fixed an old "juddery" brake problem on a 1966 GTV by rebuilding the servo/booster this year. But...like you, I had a broken red plastic spring perch, so had to re-assemble with the remnants... Could you let me know if/where you managed to buy that white one - thanks!
The white one came from my spares, I have a few boosters in parts that I keep around for this sort of thing. Whenever I see people selling Alfa parts I try buy old boosters.
I thought you might say that 😄 thanks for the reply - all the best with the channel.
As always simply fantastic. We all love your work. I don't have a deep stash of parts to pull spares from. What sources for booster parts do you know of. Is there a Bondi specialist supplier of components you know of or is there a kit from Classic Alfa or another supplier/ Thanks as always
For new service parts Classic Alfa carries what you'll usually need, and new boosters if you really can't repair an old one, I've linked their parts in the description of the video.
Hi Jethro, it’s been a while, any more content in the pipeline? I’ve missed your top quality videos
There's a new video up today!
I enjoyed that, although the lack of a kit of new parts always makes me very uneasy. I guess if the Cubans can manage, so can we! A couple of things I wonder about, though. It's been my understanding that brake fluid protects rubber rather than harming it. Also, if that was red Loctite, why? Last I bought it, it was labeled permanent, although very high heat could burn it away and allow bolts to be loosened but that's not the intended use. Blue is guaranteed to lock parts until you take a wrench to the fastener.
In Africa red is blue .. it’s glue at the end of the day. To be sure to be sure :-)