Leaking throttle shaft in SU carbs

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The Neck
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Leaking throttle shaft in SU carbs

Post by The Neck »

Hey everyone,

I think I've finally found the culprit to my overheating issues!!

A leaking throttle shaft. Actually two leaking shafts. I've reached out to the usual suspects to get their pricing and details on getting my throttle bodies rebuilt, and in doing so I found I was able to buy these shafts from a vendor specifically. Has anyone done this on their own? I'm pretty mechanically inclined, and was tossing the idea around in my head.

Thanks,

Mike
1968 CJ-5
2007 Audi S4
2003 Audi Allroad Stg 2
1967.5 1600
vinechoy
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Re: Leaking throttle shaft in SU carbs

Post by vinechoy »

Easy to do.....but easy to mess up.
The screws for the throttle plates may be staked on or have threadlocker on them
The throttle plates have an orientation to them. Before fully tightening, make sure that the plates fit really well into the bore, otherwise you will get air leaks and your idle will be too high.
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nismou20
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Re: Leaking throttle shaft in SU carbs

Post by nismou20 »

A leaky throttle shaft and overheating? Doubt vacuum leaks to contribute to overheating. Unless it’s really running super lean.
2004 Chevy Tracker
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Linda
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Re: Leaking throttle shaft in SU carbs

Post by Linda »

See some of the Youtube videos of rebuilds on similar carbs:

Joe Curto vid
Linda
Sadly-Linda has passed away 2022. She was the 311's den mother and drove the first Rare-Parts ball joint project. RIP.
The Neck
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Re: Leaking throttle shaft in SU carbs

Post by The Neck »

I found a fantastic guy on here that's going to rebuild the shafts for a reasonable price. Much more reasonable than me doing it and potentially screwing it up. Seems easy, but I also like peace of mind.
1968 CJ-5
2007 Audi S4
2003 Audi Allroad Stg 2
1967.5 1600
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Linda
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Re: Leaking throttle shaft in SU carbs

Post by Linda »

Z Therapy can do just the throttle shaft if I understand their website correctly.
This is the one area of carb rebuilding that is hardest to do, it appears.
Linda
Sadly-Linda has passed away 2022. She was the 311's den mother and drove the first Rare-Parts ball joint project. RIP.
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keith0alan
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Re: Leaking throttle shaft in SU carbs

Post by keith0alan »

Some of the British SU carbs have replaceable throttle shaft bushings. Easy press out, press in. Roadsters do not. Bushing involves machining out the old bushing or drilling for a bushing and then machining bushings.
The Neck
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Re: Leaking throttle shaft in SU carbs

Post by The Neck »

I ended up having a member of this forum replace the throttle shaft and went the extra mile and got the linkages straightened out. As I go through this car, I'm amazed at what the PO did to this car.

Installed last night and went for an hour drive, and then again another hour+ drive today. Carbs need to be a little more finely tuned, but the car is idling pretty good at 1k, and hasn't had a bit of vapor locking or over heating symptoms!! This was the last in a long line of issues I've been tackling over the last few months and this seems to be the last piece of the puzzle.

Time to put some miles on it before the summer winds down!
1968 CJ-5
2007 Audi S4
2003 Audi Allroad Stg 2
1967.5 1600
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