350tbi throttle shaft bushings and shaft seals need help please asap

[mrgoodwrench]

My throttle shaft has play and binding im trying to install throttle shaft busings to fix it. I ordered a boring bit and bushing kit on line for a q jet carb since i could not find one listed for a 350tbi and others on line said it was the same and would work. Tore my 350 tbi apart and my shaft measures .370 so i would assume that means i need a 3/8 id throttle shaft bushing and the ones in the q jet kit are way smaller. Can anyone tell me where i can get a boring bit shaft bushings and seals for my rig? Also in typical idiot fassion im running late and leaving to my anual 4x4 trip in a few days. Ck5 geniuses please help save my bacon. Thanks mike

 

[Wes Harden]

https://www.carburetor-parts.com/carburetor-bushings has bushing listed by size.

you need to measure the thickest diameter of the throttle shaft and order a hand reamer .001-.003" larger, Amazon has quite the selection. Possibly an adjustable one. thought adjustable that small might be very hard to source quickly. Long pilot style makes reaming both square to each other much easier by hand.

You may need to suck it up and grab a rebuilt unit to slap on the truck for your trip. idk what time line for shipping would be.

 

[dyeager535]

Since you are in a hurry, another option is to just go to a wrecking yard and find another tbi. They are near universal, and if your parts are good otherwise (TPS, injectors, IAC) you could swap those over along with a gasket/seal kit. Or, just switch the portion that houses the throttle shaft, but I doubt that makes a ton of sense vs. just getting a complete TBI whether new or used.

No idea what the 'yards get for those vs. rebuilt, just depends on your budget, availability of options, and what you prefer to do.

FWIW, these guys were local to me, and they used to rebush the Q-jet throttle shafts, and I see they list TBI now as well. May not work with your timeline, but if they could get you guaranteed right parts quickly, perhaps an option too? https://carbsunlimitedandperformance.com/

 

[mrgoodwrench]

Thanks guys

 

[mrgoodwrench]

If the shaft measures .370 you would go with a 3/8 bushing id right? And the .005 diffrence is probably just needed clearance?

 

[Wes Harden]

the way I understand it the bushings are all id under size, or when pressed into the housing the id shrinks a bit. The reason they need to be reamed to fit.
even if you got the correct id I believe it changes when pressed in. Reaming will also square up the center of each bushing so the shaft doesn't bind. I haven't done this job myself, I do have the tools for a qjet and will do mine when the time comes. I plane to use a drill press and x-y vise. Turn the chucked ream by hand. Note never turn a ream backwards it will dull the blades.
measure everything the current bushing id and od go from there find the closest bushing. you should have a driver that fits the bushing to install in tbi body

 

[mrgoodwrench]

the way I understand it the bushings are all id under size, or when pressed into the housing the id shrinks a bit. The reason they need to be reamed to fit.
even if you got the correct id I believe it changes when pressed in. Reaming will also square up the center of each bushing so the shaft doesn't bind. I haven't done this job myself, I do have the tools for a qjet and will do mine when the time comes. I plane to use a drill press and x-y vise. Turn the chucked ream by hand. Note never turn a ream backwards it will dull the blades.
measure everything the current bushing id and od go from there find the closest bushing. you should have a driver that fits the bushing to install in tbi body

I plan to use a long bolt with smooth shank and a washer as a driver. I found a 3/8 kit on amazon says i will have it tue and i leave thurs so fingers crossed or i will put it back or dig a spare out of the shed.