Carb throttle shaft play

[rusty_sherpa]

Currently going through the vacuum lines and carb. I noticed gunky varnished gas at the main throttle shaft. It also has a fair amount of play - approximately 1/32” or a little less than 1 mm. I’m thinking it’s also causing a vacuum leak.

I did a search and found mentions of bushing replacements. Are they still available and by whom?

 

[rusty_sherpa]

…to close the loop on the thread. I installed new bushings from a Quadrajet carb repair kit. Requires very minor modifications. Very easy. Worked out great. Snug as a bug in a rug.

Instagram link with some videos.

 

[CruiserTrash]

@rusty_sherpa This is great tech. Thanks for the show and tell. Time to go check my carb...

 

[rusty_sherpa]

@rusty_sherpa This is great tech. Thanks for the show and tell. Time to go check my carb...

Yep. I didn't find much on the topic. Best to post and let others get some info.

 

[Pz10420]

Is this the kit you bought because I am having the same issue as you? Thanks

Carburetor Bushing Installation Kit, for 5/16" Carburetor Thrott

Complete DIY carburetor bushing installation kit allows you to install bushings on your Rochester Quadrajet primary throttle shafts yourself. This kit works on all carburetors with 5/16" throt...

quadrajetparts.com

 

[Ian Crawford]

I need to do this! Great tech. Can you share a link for the kit you used?

 

[LazarusTaxa]

Did this improve your vacuum reading?

 

[joconley]

…to close the loop on the thread. I installed new bushings from a Quadrajet carb repair kit. Requires very minor modifications. Very easy. Worked out great. Snug as a bug in a rug.

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Instagram link with some videos.

Rebooting...My 84 doesn't have these bushings at all. Just a thin metal washer/shim as you've shown in your pics. Do you think the bit in the kit would cut into the cast enough to create space for the bushings?

Both of my shafts show signs of leaking, with larger pooling fuel underneath and causing vacuum stumbling after a full rebuild.

 

[rusty_sherpa]

My spare carbs either have or don’t have the bushings. The process would be the same. You’d use the special bit to ream the shaft holes, insert the new bushings, and use the bit again to hone the bushing to loosen the fitment a tad. The latter is to minimize any binding in the throttle shaft throughout the sweep. FYI, I haven’t come across a secondary shaft that needs rebuilding. It may have very slight movement but it should be ok. I did this one time for proof of concept. The main shaft takes the brunt of the torque resulting in accelerated wear.

 

[joconley]

Thank you, sir. Glad to hear about the secondary shaft. Apologies on the delay, I missed the notification. Will try to document and report back after the job. Thanks for the response and the detailed writeup and pictures on the earlier job.