hopefully you still read comments for old vids, great video, really helpful! but why do they have 2 pressure switches? my brake lights were stuck on, i unplugged one of the switches and they work fine now, so whats the 2 switches do?
It's a fail safe / backup for when one switch or brake master cylinder piston / circuit fails... also, a pressure difference between the two brake master cylinder pistons (brake circuits) will illuminate a warning light in the cluster (the one that lights up when the parking brake is pulled) when the brake pedal is pushed.
Got my shiny new part and am itching to start, but I just called my third parts store and got the same "Rubber grease?" What exactly am I looking for and why does nobody know what this is?
Thomas, Thanks so much for this. Made the job so much easier to know what was ahead. So satisfying to step on the pedal and have full pressure. I've used the wheel bearing video as well. Thanks for taking the time to film.
Hey Thomas, are you saying that provided you didn’t have air in the lines before you did the MC, and you do the bubble technique you showed that you don’t need to bleed the brakes? I just took my 85 out for a ride withou bleeding and it seemed fine. No squishy pedal. Good stopping power. Drove for about twenty minutes through hilly towns. I don’t want to bleed it if I don’t need to. Thanks!
Thanks Thomas. Pedal was firm from the start. No sign of any typical sinking or squishiness. I have to say I have learned a lot from you. I would never have attempted half the shit I’ve done on my van without checking your TH-cam first. So, THANK YOU.
Hey Thomas. That is one interesting design that you have to pull the cluster to change the master cylinder. Tell me that I'm wrong, but it looks like you have to pull the top plastic cover to check the brake fluid? Thanks for the video!
stuzman52 Yeah, just pull the brown cover and you can check brake / clutch fluid... changing the brake booster or pedal assembly is even more fun (dash removal required).
ciao thomas, Ho una vw t3 air e ho il pedale del freno che con il motore che scende fino alla fine della corsa, devo sapere se dipende dal cilindro principale del cilindro principale o dal cilindro che si trova appena sopra il pedale del freno? grazie per la risposta Alessandro padova italia
The master cylinder is in backwards in that car. I replaced the booster on my T4. They give you just enough wiggle in the brake lines and room to pull the booster out from behind the master cylinder.
I can't believe that you we're sitting on the job no seriously I never replace one yet what was the issue low pedal or no pressure to one or both of the master ports my bet is that if you applied pressure to the brake pedal the pedal would go down slowly ? I see that it was the vanagon week I see at least 3 of them.
V10PDTDI Yes, pedal dropped slowly the first half of application... pumping the pedal quickly can hold pressure, but if you apply slowly as you come to a stop, the pedal would sink. I've replaced a few since working on VW's, but you are right, it's not a common issue (just like with any model, as long as the brake fluid is flushed regularly).
V10PDTDI I have done one mk4. A few mk3... we usually see cars that have prior lack of service (brake fluid flushes). Once the customer sticks with us, we flush on a regular basis.
Basically bench bleeding, but if you let the air out at those fittings, you shouldn't have to bleed the rest, since no air could have entered the open lines (fluid would have to come up & out to allow air to go down).
What kind of ratchet/extension/joint/socket setup are you using for the fasteners? That seems like an incredibly useful setup for tight spaces where space is very limited. Maybe something for tool of the week?
***** I've seen these in your videos before, for the life of me I can't understand why I didn't pick up on the shallow-socket being part of the joint. Thats perfectly sensible. And genious.
I am replacing one soon. I saw that you opened up the connections to the master cylinder looking for air bubbles. Wondering if, during this process, you were tapping the brake pedal. Not a critique...just want to ensure I do it right!
When the brake pedal is in the rest / off position, the ports in the MC are open (so that fluid can return into the reservoir)... with the ports open, fluid can freely drip from the fitting port, letting / pushing the air out. If you want, you can apply pressure and push the air out. Before releasing the pedal, close the fitting so that no air is sucked back in. Open / loosen the fitting again and push the pedal... close the fitting and release the pedal. Whichever method works best for you.
Typey1 This is only for master cylinder bleeding... if you have air in the lines, you will still have to pressure bleed at the wheel cylinders / calipers.
do I can even use this method of bleeding when I’ve changed the whole part with brake booster and cylinder? BTW: nice Videos Thomas! Always helped me out in the past 👍🏻Thx
@@EXOVCDS if you purchase the master with the 3 prong switches all ready installed (part # 251611021c) and your existing plugs are 2 prong, can you just bend the outer prong out of the way and your good?
hopefully you still read comments for old vids, great video, really helpful! but why do they have 2 pressure switches? my brake lights were stuck on, i unplugged one of the switches and they work fine now, so whats the 2 switches do?
It's a fail safe / backup for when one switch or brake master cylinder piston / circuit fails... also, a pressure difference between the two brake master cylinder pistons (brake circuits) will illuminate a warning light in the cluster (the one that lights up when the parking brake is pulled) when the brake pedal is pushed.
now that's the weirdest location ive seen for a master cylinder.
Got my shiny new part and am itching to start, but I just called my third parts store and got the same "Rubber grease?"
What exactly am I looking for and why does nobody know what this is?
You can leave it dry... or lube it with a bit of brake fluid. Rubber / silicone grease just keeps the seal from drying out and cracking prematurely.
Good job & training video. I can hack it now.
Regards. Thank you.
I don't know about training video... but thanks for watching!
Thomas, Thanks so much for this. Made the job so much easier to know what was ahead. So satisfying to step on the pedal and have full pressure. I've used the wheel bearing video as well. Thanks for taking the time to film.
Thank you for watching!
Hey Thomas, are you saying that provided you didn’t have air in the lines before you did the MC, and you do the bubble technique you showed that you don’t need to bleed the brakes?
I just took my 85 out for a ride withou bleeding and it seemed fine. No squishy pedal. Good stopping power. Drove for about twenty minutes through hilly towns.
I don’t want to bleed it if I don’t need to.
Thanks!
Correct.
If pedal is firm / does not pump up... no air in system.
Thanks Thomas. Pedal was firm from the start. No sign of any typical sinking or squishiness. I have to say I have learned a lot from you. I would never have attempted half the shit I’ve done on my van without checking your TH-cam first. So, THANK YOU.
hi you say theres 2 oxygen sensors i borrow a OBD diagnostivs tool but it doesent say wich one to change shit can you advise me please thanks
Hey Thomas. That is one interesting design that you have to pull the cluster to change the master cylinder. Tell me that I'm wrong, but it looks like you have to pull the top plastic cover to check the brake fluid? Thanks for the video!
stuzman52 Yeah, just pull the brown cover and you can check brake / clutch fluid... changing the brake booster or pedal assembly is even more fun (dash removal required).
***** Smiling....simply unbelievable Thomas!
ciao thomas,
Ho una vw t3 air e ho il pedale del freno che con il motore che scende fino alla fine della corsa, devo sapere se dipende dal cilindro principale del cilindro principale o dal cilindro che si trova appena sopra il pedale del freno? grazie per la risposta Alessandro padova italia
The master cylinder is in backwards in that car.
I replaced the booster on my T4. They give you just enough wiggle in the brake lines and room to pull the booster out from behind the master cylinder.
Garth Goldberg Thanks for the info... will keep it in mind!
Just did my first ever brake master cylinder replacement and brake bleed. This video was super helpful!!!
Nice to hear that my video was of help... thank you for watching!
The best I’ve seen for this job!! Thanks for making this video!
Kind of you to say, thank you and thank you for watching!
I can't believe that you we're sitting on the job no seriously I never replace one yet what was the issue low pedal or no pressure to one or both of the master ports my bet is that if you applied pressure to the brake pedal the pedal would go down slowly ? I see that it was the vanagon week I see at least 3 of them.
V10PDTDI Yes, pedal dropped slowly the first half of application... pumping the pedal quickly can hold pressure, but if you apply slowly as you come to a stop, the pedal would sink. I've replaced a few since working on VW's, but you are right, it's not a common issue (just like with any model, as long as the brake fluid is flushed regularly).
The cars that I replaced the most master cylinder is probably my 2's but I can't remember replacing a master on mk4 or 5 !
V10PDTDI I have done one mk4. A few mk3... we usually see cars that have prior lack of service (brake fluid flushes). Once the customer sticks with us, we flush on a regular basis.
Great video. I've never tried bleeding the master by cracking the lines and waiting for the bubbles to stop.
Basically bench bleeding, but if you let the air out at those fittings, you shouldn't have to bleed the rest, since no air could have entered the open lines (fluid would have to come up & out to allow air to go down).
Thanks! Very helpful, just did both this and my clutch master. Much appreciated.
+Daniel McLean Thank you again for watching... some of my older videos definitely aren't the greatest. Nice to hear that they were of help!
Whoa ! Thankyou to have taken the time to make that video ...
Thankyou!
Thank you for watching!
What kind of ratchet/extension/joint/socket setup are you using for the fasteners? That seems like an incredibly useful setup for tight spaces where space is very limited. Maybe something for tool of the week?
pr0xZen 1/4" craftsman ratchet, 1/4" snap-on extension (14" long) and a 13mm snap-on swivel socket (universal joint)
***** I've seen these in your videos before, for the life of me I can't understand why I didn't pick up on the shallow-socket being part of the joint. Thats perfectly sensible. And genious.
My master cylinder is looking like the same but I have no leaks and it is working fine ,should I replace it ??
If it's not leaking and the pressure feels good... you can leave it. If you want to replace it "just in case", sure, you can do that. =)
Thomas EXOVCDS thank you
Did you tap the brake pedal at all when you were getting the air out of the master cylinder? I suspect you were not.
Point being?
I am replacing one soon. I saw that you opened up the connections to the master cylinder looking for air bubbles. Wondering if, during this process, you were tapping the brake pedal. Not a critique...just want to ensure I do it right!
When the brake pedal is in the rest / off position, the ports in the MC are open (so that fluid can return into the reservoir)... with the ports open, fluid can freely drip from the fitting port, letting / pushing the air out. If you want, you can apply pressure and push the air out. Before releasing the pedal, close the fitting so that no air is sucked back in. Open / loosen the fitting again and push the pedal... close the fitting and release the pedal. Whichever method works best for you.
Good video, I think I'd try your method of bleeding from connectors
Typey1 This is only for master cylinder bleeding... if you have air in the lines, you will still have to pressure bleed at the wheel cylinders / calipers.
do I can even use this method of bleeding when I’ve changed the whole part with brake booster and cylinder?
BTW: nice Videos Thomas! Always helped me out in the past 👍🏻Thx
Awesome video and explanation
Thank you and thank you for watching!
Another great video, this my next item on my list. Btw, I thought for a second you were squirting dish soap in the reservoir.
Possibly! LOL
@@EXOVCDS if you purchase the master with the 3 prong switches all ready installed (part # 251611021c) and your existing plugs are 2 prong, can you just bend the outer prong out of the way and your good?
@@dprovini I would think yes... the 2 prong plugs might fit without having to bend anything. Have you already tried?
No I have not. To be safe I was just going to buy new switches.
BTW what brand of Rubber Grease do you use. thanks again. Will caliper grease work? Stuff is hard to find
Nice work!!
ehsin sabir Thanks for watching!