Throttle shaft bushings? - Motorcraft 2100 carb

[admin]

The idle on my '72 has been getting progressively worse and I finally braved the oven I call a garage (AZ in the summer) to dig into it. It looks like the throttle shaft holes are pretty wallowed out. At first I thought my problem was the base plate not sealing, because a shot of carb cleaner near the base while running would kick up the idle speed. But with a bit more testing it looks like the leak is at the throttle shaft.

So has anyone had luck with the throttle shaft bushings? Seems pretty straight forward; drill out the shaft holes then press in the bushings. But I'm a little concerned with getting them in perfectly straight. Also, is this a long term fix or just a short term band-aid?

Thanks!

 

[broncodriver99]

I haven't done a 2100 but have done a couple of q-jets. Worked great. I bought a kit that included the bit and a guide and it is easy. Lemme see if I can find the kit I bought.

 

[broncodriver99]

These guys both carry the same kits. I can't remember who I bought what from but I picked up a 3/8" and a 5/16" kit.

http://www.cliffshighperformance.com/bushings.html

http://quadrajetparts.com/quadrajet-throttle-shaft-bushing-c-128_34.html

I believe the Motorcraft shafts are 3/8". The drill bit is turned down so that most of the length is used as a guide. I don't see any reason it wouldn't be a permanent fix. The bushings should wear better than the aluminum casting.

 

[jckkys]

The Ford 2100-2150-4100s are basically the same as Holley 2 and 4 bbls in that the shafts are about 3/8" diameter. Oddly the 2100 and 4100 primary shafts are 0.372" diameter. I'm not sure if 0.003" more clearance would be a problem. The 4100 secondary shafts are 0.375" or exactly 3/8". I do see bronze bushings as longer lasting than the original aluminum throttle shaft bores. When searching for throttle shaft repair kits you'll find a majority are made for Q-junks that seem to need this repair more often than other carburetors.

 

[broncogt]

http://www.rodscarburetors.com/

http://www.rodscarburetors.com/

Its been a while since I have had any work done here. They repaired the shafts a used Weber 2bbl for me and the work was ok.

 

[jckkys]

I think I'll talk to them too. The cost of a reamer for one use, it makes sense to let someone who's done it a few times, do mine.

 

[admin]

http://www.rodscarburetors.com/

Its been a while since I have had any work done here. They repaired the shafts a used Weber 2bbl for me and the work was ok.

Thanks. I've used Rod's in the past too. But I tried calling them several times today and the phone just rang and rang. No answering machine. Hopefully they're still in business.

 

[Show Links]

I used Carb Junky's 3/8" bushing kit and reverse reamer with good results. I also purchased sanding reamer because, after reaming the new 3/8" throttle shaft hole, it was slightly too tight for the bushing. You need a large variable hand drill. Use plenty of drill bit oil and take your time.

Good luck and have fun with it.

Rob

 

[sykanr0ng]

Back when I looked at bushings for a carb they were made of Oilite bronze.

The only thing that would outlast them would be ball, roller or needle bearings.

 

[admin]

I ended up taking the carb back to Rod's and they re-bushed the throttle shaft for no charge. They had rebuilt the carb, but it had been a few years and I didn't have the receipt. But it still had their metal tag and they didn't hesitate to take care of it, which was nice to see. They also found the accelerator pump diaphragm was leaking, so they replaced that. I was in and out for $12 and the Bronco now runs great!