I want to order and replace my primary throttle shaft bushings since they are badly worn. Anybody know where I can get these bushings and how many of them I need to get?
The carb is not manufactured with bushings. It is metal-on-metal... shaft on throttlebody. The repair involves machining the throttlebody oversize, and pressing in a piece of thin metal "bushing" to restore the throttle shaft bore to its original dimension. Some kits come with pre-cut bushings, but most come with a piece of bushing material which must be cut to length for each hole being serviced. If the bushing ends up being too tight (and it does sometimes) you must then hone or broach it to match the shaft for proper clearance.
Some kits come with broaches. None come with flex hones (which is what I use).
The "butterfly" discs must be carefully removed and re-installed to do this job. If you don't have a surgeons touch, and if you don't re-install the discs "centered", you can bubba the carb.
Yikes! :eek: I try to do as much as I can on my own but this sounds like it might be something I should get done by a pro. There is a Quadrajet guy in town that I have heard good things about but he wants $300 (Canadian) to rebuild my carb. *sigh*
For $300 he'd better kiss you after he has sex with you. :)
A bushing job should only cost between $30 and $60 depending on how many holes need to be done.... about $15/bushing.
Most secondaries are designed to be extremely loose.... I only bush these if they are really bad. Primaries take a beating because of the carb return spring.
Carb kit prices vary. You can probably get away for less than $100 including a "re-bush" if you hook up with the right mechanic.
LARS is the Q-Jet guru here on the forum... and there are several other famous people who do the Q-Jet thing. $300 is too close to the cost of a new carb.... and more than the cost of a shiny new Holley. Not cost effective in my opinion.
300 dollars is way excessive for that job.I've had one or two of mine done and helped on a few others,its not that big a deal.If you want,I can recommend a shop near me,and you can ship them the base plate or the whole carb to be rebuilt,good quality work.Whatever you do,run,dont walk away from the 300 buck job. :eek:
Boofers -
First, make sure you really need to bush the shaft. The Q-Jets were sloppy on the mainshafts when they were brand new, and it has to be REALLY sloppy to actually affect performance. The small amount of air that leaks in the throttle shafts does not affect idle or performance - you're sucking far more air through the PCV than you're leaking through the shafts. The only time I bush the shafts is when they're so sloppy that the carb does not return to a consistent idle setting due to the throttle plates jamming in the bores from shaft slop. Even on a really badly worn carb, only the driver's side primary shaft usually needs to be bushed. There is no load on the passenger side, and no load on the secondary shaft.
To do the bushing job, you need to remove the throttle plate off the carb, grind off the staked throttle blade screw ends, remove the throttle blades, pull off the secondary throttle linkage/springs, and pull the fast idle linkage off the primary shaft. You can then pull the primary shaft out of the throttle plate, ream the shaft hole, press in a bushing, and re-assemble the whole thing.
I can bush it for you if you actually need it done. Send me just the throttle plate, and I'll do the whole operation for you. Drop me an e-mail if you need info on this. I believe Tom454 has also done a few bushing jobs and knows the process.
I spoke with the Quadrajet guy in my area. The $300 includes cleaning, a shiny coating, setup of all the levels, new parts including needle and seat, acc pump, gaskets, etc. He didn't want to just do a rebush for me. He tried to sell me the whole $300 package, figuring I am a believer that Quadrajets are black magic. He obviously doesn't know about this forum :D
Anyways, my throttle plates close fine until I attach my return springs to the throttle lever. Due to shaft slop the springs manage to pull the throttle shaft sideways enough so that the plates dont return all the way closed. I can close them by hand and I can also quickly tap my gas pedal to get the throttle to "snap" all the way closed. I was thinking of just attaching my return springs to a different location to reduce the side force on the shaft *ahem bubba*
I'll see how it goes and Lars maybe you'll hear from me, thanks for the offer.
Anyways, my throttle plates close fine until I attach my return springs to the throttle lever. Due to shaft slop the springs manage to pull the throttle shaft sideways enough so that the plates dont return all the way closed. I can close them by hand and I can also quickly tap my gas pedal to get the throttle to "snap" all the way closed.
That's exactly what my carb used to do. A forum member sent me over some bushings & I fitted them a couple of months back. The job is so easy to do (if you take your time) that I wouldn't pay somebody to do it. The bushes had an OD of 11/32" so you'll need a reamer to size the holes in the carb. On the d.side the reamer self centred itself as the carb body was so worn, but the p.side (which I also did) wasn't as worn so the reamer wouldn't start. An 8.5mm drill was just the right size to pull itself centrally through the (worn) hole & took out enough metal for the reamer enter the hole centrally. I just pushed the bushes in after coating them with some Loctite & the carb is now as good as new with a regular idle speed every time & a much smoother idle (the popping in the exhaust on deceleration has also stopped). The bushes I had were pre-sized with an ID of 5/16" & didn't need any work for the shaft to fit.
As I said, it's an easy job to do & the result makes for a much nicer running engine (it was driving me insane having an idle speed of 600rpm at one junction & then 1100rpm at the next junction!), but if the thought of drilling/reaming holes through your carb is a bit scary(!!) you could always send it to somebody else to do (Hi Lars :thumbs: ). I also did a complete refurb "while I was at it", changing the needle, seat, seals, etc,etc & the entire cost was less than $100 (even allowing for postage & duty on parts) so, yes, run away very quickly from that $300 quote!
:cheers:
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Rochester Quadrajet primary throttle shaft bushings
