Can I rebuild my own Throttle Body?

In the long list of things wrong with my truck I found another... I did the old hook up a bicycle inner tube to the upper IC trick to check for vacuum leaks. Well the throttle body is leaking out the shaft like crazy.

I know of several options and frankly I'm not sold on any of them just yet.

I understand that our throttle body has SyTy specific linkage and that a TPI IAC circuit on the bottom of the Throttle body is desirable unless you want to find a ZR1 IAC for an LT1 throttle body, which I'd rather not mess with.

Matt Blum no longer rebuilds our throttle bodies. I could get a $150 rebuild on e-bay with machining for 52mm blades but I'd have to deal with the hassle of shipping my TB out and paying for shipping both ways taking it up to ~$180 and a week or two of downtime. I could buy an aftermarket TB, either 52 or 58 mm but the performance of the stocker is adequate and I'd still have to deal with switching linkage around.

Can I rebuild my own throttle body? Has anyone made a tutorial? How do you get the linkage off? I read that it has to be drilled to be removed. Looking at the end of the TB shaft it looks like the end has been 'blunted' to keep the linkage on. Is that all that holds the linkage on? If you were to drill or mill end of the shaft is there room to 'blunt' it again? It seems as though the combination of the throttle cable and TV cable pulling on one side of the shaft really wears out the bushings on the syty throttle body. Has anyone tried case hardening the shaft and sourcing some more durable bushings? Are there any o-rings or seals inside that need to be replaced?
 

Ty 1885

New member
Re: Can I rebuild my own Throttle Body?

Yes you can rebuild your own.
First you need to remove tps sensor, then remove all of the srews holding the butter flies.
The shaft should slide out from the linkage side. Next you need to ckeck that the shaft is the same size all the way (not worn out), if the shaft is okay, then you need to get brass sleaves to install in the TB.
Then you need to very carefully drill out the TB so that the new sleaves fit snug, then lube the shaft with grease and insert it into the TB.
The fun part is putting the butter flies back so that they dont come in contact with the TB.

That is it!
 

Don W.

Stab it and steer it
Re: Can I rebuild my own Throttle Body?

I've done this (except for the bushings) and, yes, the trick is centering the butterflies. They should be beveled so they only go in one way. Once that's done you'll probably want to remove the plug (if it's still there) over what you would think of as an idle speed screw (but that's not what it is). Use that screw, and the butterfly retainer screws, to center and adjust the butterflies so they fully close. EDIT: Without binding. (The IAC controls idle speed and needs these closed to do that.)

HTH
 
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Re: Can I rebuild my own Throttle Body?

Yes you can rebuild your own.
First you need to remove tps sensor, then remove all of the srews holding the butter flies.
The shaft should slide out from the linkage side. Next you need to ckeck that the shaft is the same size all the way (not worn out), if the shaft is okay, then you need to get brass sleaves to install in the TB.
Then you need to very carefully drill out the TB so that the new sleaves fit snug, then lube the shaft with grease and insert it into the TB.
The fun part is putting the butter flies back so that they dont come in contact with the TB.

That is it!

Sounds like a nice challenge. Where can I get the brass sleeves? Never seen them for sale anywhere.
 

Don W.

Stab it and steer it
Re: Can I rebuild my own Throttle Body?

Most any bearing house will have them I would think. My problem is how do you dead center the drill?? If the TB is worn then the hole is out of round a little making drilling a problem. But, like I said, I've never done it maybe I'm full of it...:rotf:
 

warmpancakes

New member
Re: Can I rebuild my own Throttle Body?

throttle body is a tuned port one with a bracket added, just move the bracket to a rebuild off ebay
 
Re: Can I rebuild my own Throttle Body?

throttle body is a tuned port one with a bracket added, just move the bracket to a rebuild off ebay

Thought about that but the e-bay rebuilds are for TPI camaros and corvettes. Do they utilize the same throttle/trans linkage as a SyTy? The same vintage vehicles would have utilized the same trans but I thought I heard the linkage was designed with specific rates for our trucks.
 
Re: Can I rebuild my own Throttle Body?

Yes you can rebuild your own.
First you need to remove tps sensor, then remove all of the srews holding the butter flies.
The shaft should slide out from the linkage side. Next you need to ckeck that the shaft is the same size all the way (not worn out), if the shaft is okay, then you need to get brass sleaves to install in the TB.
Then you need to very carefully drill out the TB so that the new sleaves fit snug, then lube the shaft with grease and insert it into the TB.
The fun part is putting the butter flies back so that they dont come in contact with the TB.

That is it!

That's some bad intel... The fasteners that hold the butterflies don't just unscrew. I thought it was a little odd that GM would just have a few screws in the intake tract with nothing to keep them from backing out, save for some loctite. The ends have been mechanically formed into a 'bullet' shape and will not back out.
 

Ty 1885

New member
Re: Can I rebuild my own Throttle Body?

That's some bad intel... The fasteners that hold the butterflies don't just unscrew. I thought it was a little odd that GM would just have a few screws in the intake tract with nothing to keep them from backing out, save for some loctite. The ends have been mechanically formed into a 'bullet' shape and will not back out.[/QUOTE

You can still unscrew them. You can evan reuse them.
 

4C FED

Absolutum Dominium
Re: Can I rebuild my own Throttle Body?

That's some bad intel... The fasteners that hold the butterflies don't just unscrew. I thought it was a little odd that GM would just have a few screws in the intake tract with nothing to keep them from backing out, save for some loctite. The ends have been mechanically formed into a 'bullet' shape and will not back out.[/QUOTE

You can still unscrew them. You can evan reuse them.

Yeah, just use red Loctite on them so your motor doesn't eat them.
 
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