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My 1986 Pontiac 305 TPI throttle body has a leak by the return spring shaft . What is the best option for this? Replace or repair? I can only find one place that sells the replacement one and its out of stock. Thanks
Repair is not impossible, but the staked-on bellcrank for the linkage makes it a little more complicated than it could be. Reaming and bushing the throttle shaft bore (often just the outer one) can restore it to a like-new condition if done correctly.
If the outer bushing hole is counterbored just a little deeper than is necessary for the bushing, an O-ring can be installed between the bushing and outboard seal.retainer as a redundant seal.
I had a throttle body re-bushed by "Dr. Injector Motorsports" some years ago. The web site is still up and running but I'm not sure if they are still doing re-bushing on TPI throttle bodies. What they did was grind off the peened over metal on the passenger side of the throttle shaft. The throttle blades are removed and the shaft slide out. They install new bushings. The throttle shaft is re-installed and it is tack welded on the passenger side.
If a guy had a lathe available, the shaft could be chucked up and center-drilled, then drilled and tapped for a fine-thread cap screw and large washer to hold the belcrank in place. That stamping had a square opening to engage flats on the throttle shaft, so slippage should not be an issue.
I used a flat punch and moved the shaft metal so the tps lever could be pulled off. When i was done, i gently moved the metal back over the lever. Been fine for 20 some yrs
