Just finished rebuilding my carb for my 74' and am concerned about excessive slop at the primary throtle shaft. I have either heard or read that bushings can be put in to eliminate this. Does anyone know of a kit, or parts to do this? Has anyone done it and how hard? And last, do you need special tools, I.E., a pilot drill of some sort? Thank you for your time, Corky.
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Throttle Shaft Bushings.
Corky: I'm not experienced with Quadrajets except for the standard rebuild process, but I've repaired many Holley's with this problem, so my answer here is based upon Holley's. Yes... special tools are required. Although the tools do come in kits, the kits consist of standard machinist's equipment. The primary tool is a piloted reamer which cuts the throttle shaft bore to an oversize. The pilot tip keeps the reamer centered in the bore so that the bushing can be installed properly. Next, a thin-wall bushing is cut to length, and pressed in using a special bushing driver. The driver is needed to avoid "mushrooming" the bushing. A "cutter" tool is usually provided with the kit which is supposed to be used to trim the bushing after it's installed, but, the trimmer makes a mess of an otherwise good job... I never use the t******* tool, I cut the bushings to length before I install them. After the bushing is installed, it is sometimes necessary to hone it for proper clearance so the shaft doesn't bind. I use small diameter flex-hones for this step (not in the kit), although occasionally a broach (included in the kit) will suffice. I purchased my "kits" many moons ago from an automotive machine shop supply house (Lacey-Williams) who in turn ordered the kits from a company named "K Line". If you're interested, let me know and I'll provide the K Line part number(s). The kits come in different sizes, 5/16 and 3/8 being the most widely available. PS- the primary culprit causing worn throttle shaft bores is poor engineering. The throttle shaft should never be used as a "pivot" point for the return spring. I re-engineer my own vehicles (and customers if desired) to eliminate the pressure on the throttle shaft bore by installing a return spring directly in line with the direction of pull of the throttle cable/rod, instead of using the shaft/bore as a pivot. Tom -
Re: Rochester carburator bushings
Corky, Tom's advice is spot on. If you have access to a lathe equipped with a 4-jaw chuck, e-mail me and we'll take this off the Board. RegardsComment
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Re: Rochester carburator bushings
Corky----
Most of the major carburetor rebuilders can perform this repair for you at a very modest cost if that's all you want done. They have the tools and experience to do it. This is the type of repair operation that's best done this way. I usually do repair operations on my own cars that few others will tackle. But this one! It just doesn't make sense. Brad Urban's Carburetor Shop in Rancho Cucomonga, CA did mine for me.In Appreciation of John HinckleyComment
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