Cadillac 472 Fuel System Part 2 - Quadrajet - Throttle Shaft Bushings and Sealing Casting/Well Plugs

#impalamansgarage1
In this video we install primary throttle shaft brass bushings to remove slop and ensure an air tight fit. We also seal up the casting plugs to correct a well known Quadrajet defect whereby gasoline leaks from the bowl down into the intake manifold. Some may elect to bore out the well plugs,
tap them and screw in replacement plugs - and THEN apply epoxy.
This is perfectly fine. What I am doing by simply applying epoxy is
somewhat of a risk but it's cheap! It may in fact leak down the
road. If it does I'll take it apart again! Both of these issues greatly
affect idle quality and fuel economy.
Notes:
1971 Cadillac Deville 472 Rochester Quadrajet Carburetor Model: 7041230
Parts and Materials Used for these repairs:
Accelerator Pump: (withstands today's fuel with alcohol / ethanol)
quadrajetparts.com/quadrajet-...
Epoxy
www.jbweld.com/product/waterw...
Bushing Kit
cliffshighperformance.com/Qua...
Carburetor Kit
www.oreillyauto.com/detail/b/...

[@TheCanadianBubba]

A fellow stopped by and recommended your videos, thanks for posting them !

[@ImpalamansGarage]

Thank you sir. Glad to help.

[@Jeff_Pendleton]

I am appreciating this video. I did the quadrajet on my '75 Eldorado maybe 15 years ago. I was never sure what to really do with those well plugs. I had the overnight leakdown problem that persisted when I was done. Otherwise my overhaul seemed to work well. Next time I'll try the throttle shaft repair, which I had heard of as well, but did not attempt. You made it look pretty simple to do.

[@ImpalamansGarage]

If you can take a Qjet apart, the bushing install is quite easy using the Cliff Ruggles kit. They also sell a plug kit which requires you to drill out the plugs and then screw in their plugs. Lastly you would put MarineTex epoxy on it from their kit. I decided to go the cheaper route and try the WaterWeld epoxy. If it leaks, I'll remove the carb again and drill out the plugs. We'll see.

[@grand73am]

Enjoyed the video. As an option, you don't have to remove the secondary plates or shaft. You can remove the linkage on the driver side of the secondary shaft, and leave the secondary shaft and plates in place. Then you can disconnect the secondary linkage from the primary linkage, and pull out the primary shaft. Removing the secondary linkage is takes a bit of figuring out, so pay attention to the dissassembly, even taking pics while doing it, so you can put it back like it was. Here are instructioins from the book "rochester carburetors" by Doug Roe: "first....pry end of inner spring off its ledge, then catch it with finger, and allow it to unwind (it only unwinds one full turn. that's how you'll rewind it when reinstalling). Next, release tension on outer spring by removing the straight end of the spring from its tang with pliers. Hold secondaries closed while rotating lever clockwise to let the spring clear its slot in the shaft end."

[@ImpalamansGarage]

😅😅 Thanks! I have a copy of that book as well. Reckon I should read it. 😀

[@grand73am]

@@ImpalamansGarage Page 138, pics and instructions at the bottom of the page 🙂. Also look at page 140.

[@wernerdanler2742]

I have been subscribed for some time now but I just turned the bell on. You got me hooked on this carb so I want to see it finished as soon as you get the parts. How's the 300sd running?

[@ImpalamansGarage]

Doing well but the it is now clear that the engine dampening shocks have to be replaced. The whole car rocks gently from side to side with each revolution of the engine. Engine doesn't miss a beat but I think that many people often confuse this oscillation with and engine problem. It will drive you bonkers, as it has me. Engine mounts will get replaced as well. Soon.

[@wernerdanler2742]

@@ImpalamansGarage hi. I replaced the shock on my 300d and it made no difference on the engine's rocking. Probably should have replaced the mounts.
The mounts on my e320 are hydraulic and when they go bad the engine vibrates like hell. I replaced them and now it runs smooth as silk.
Have a great weekend!

[@DarthMayers]

Thanks for the video. wanted to ask what size is the bit? I see two size kits on cliffs a 5/16 and 3/8. 🤔

[@ImpalamansGarage]

The primary shaft is 5/16 and the secondary one is 3/8.

[@DynamicSeq]

I find that soda blasting with baking soda and a good wash, with soapy water will clean it like brand new...

[@steelcantuna]

Has your JB Weld lasted over the last 2 years. Everything I have researched says it just doesn't last even a year. People recommend Marine-Tex but say it isn't a permanent solution either. Just curious, I'm fixing my tonight.

[@ImpalamansGarage]

So far so good. The Marine Tex is the best stuff to use. I have used it in the past for this job but I did not feel like ordering it and waiting a week. LOL..... you can't get it anywhere around here locally that I know of. I used the water-weld stuff that is made to be used in a gasoline environment. i don't think conventional JB Weld can stand up. I used marine tex to rebuild a broken plastic front cap on a tractor. th-cam.com/video/BP8fqawbv_0/w-d-xo.html

[@chrismc410]

I wonder if cerrosafe or 20:1 casting lead would work instead of epoxy

[@ImpalamansGarage]

The preferred epoxy is actually Marine Tex. cliffshighperformance.com/product/bottom-plug-kit I just didn't feel like paying $30 bucks for it.

[@zealandwylie489]

Where can I find a rebuild video or diagram for this carb?? I can’t find anything online. All the diagrams and videos are for a different model

[@ImpalamansGarage]

Here are two good sources of info
quadrajetpower.com/
cliffshighperformance.com/

[@ImpalamansGarage]

The best book to read is "Rochester Carburetors, Revised Edition" by Doug Roe.

[@zealandwylie489]

@@ImpalamansGarage Ok thanks. I was given this carb for free. Came off a Cadillac 472. I’m contemplating on rebuilding it or just selling as is. Not sure if it will even sell

[@zealandwylie489]

@@ImpalamansGarage also do you know where the idle compensator assembly goes?

[@daisy8luke]

Is there a reason you bought each piece individually instead of just buying the entire kit?

[@ImpalamansGarage]

Going on memory now but I believe I had a hard time finding what I needed for this older carb. I had wanted to find as many made in USA parts as I could.

[@georgekalafatis7286]

You can put glue on there if you want to I'm not fixing mine like that because that is not the correct way

[@ImpalamansGarage]

Actually Marine Tex is the absolute best sealant to use on the bottom of the well plugs.