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So here's my super-duper triple-patented patented way to re-bush those old worn-out throttle bodies that Kadron is so well known for. If anyone has any suggestions as to how to improve this method, or any other insights, thoughts, or ideas; I'd love to hear them. I'm always eager to learn....
First, we start off with high-quality German bronze bushings manufactured inside in steel casings. These are impregnated with PTFE Teflon for maximum lubrication. These bushings should last for our generation, and many more after that. These are super beefy.
Check one out against the stock bushing still inside the carb. Look how thin and skimpy that little dude is compared to these. Like I said... You won't wear these bad boys out! They're a little expensive, but well worth it.
Next, we see that if you try to get the screws out of these butterfly valves, they usually do this. They get all chewed up. They peen the back of these when they put them in so you don't suck one down in your intake system. Not a bad idea. We'll return to that thought later.
So what do you do? You drill them out. Better have some extras on hand. They'll need to be replaced, too. Also... I made a jig to hold the throttle body at he exact angle to facilitate drilling a straight hole through the retainer screw.
When you drill the screws out, you'll need to probably remove the threaded middle with an ez-out.
You might also need to chase the threads, so make sure you have a 4mm x 0.7mm tap handy Then, remove the throttle plate (butterfly). Remove the linkage arm and rotating stopper assembly and pull out the rod that goes through the throttle body.
After removing the throttle body rod, I put it in a vise and polish the shaft with strips of very fine sandpaper. I also clean the butterfly. It just looks nicer that way.
Here are a couple "BEFORE" and "AFTER" shots:
I made another jig to make the next part easy and keep the holes straight. Drill a hole in each side of the throttle body to fit the bushing. In this case, I use a 10mm diameter OD bearing (or bushing, depending on who you ask). The hole is 9.7mm deep to accommodate the bushing size.
Be careful! It's super easy to drill all the way through. Holes are much harder to "undrill", I've found.
Tap your bushings in (or press, as necessary). I'm also using a little JB Weld on mine to keep them from spinning when they aluminum heats up. If I'm going to be modifying the carb for vacuum advance, I cut a small piece of .004" aluminum wire, coat it in JB weld, and fill the little hole in the throttle body as shown. Don't fill the wrong hole or your throttle body will be instant junk! This creates the proper vacuum signal for the VW distributors when adding the port for the advance on the case of the carb. The carb was pre-designed like this, but never imported into the USA with this factory option.
After 24 hours, I return and sand the filler smooth.
Reassemble very carefully, especially when sliding the throttle plate back inside the holder. Make sure its orientation is correct, as it sits very tightly inside the body when the butterfly valve is closed. Install your new screws and tighten them only when it seats right, checking, and double-checking everything as it opens and closes.
When everything's right peen the back of the screw. I also use Loctite on mine. Assemble the linkage connecting arms as needed. Remember: Stock ones have a left and right. The "Outie" is for the driver's side, and the "Innie" is for the passenger's side. Scat linkage has the ball drilled out and both offsets point the same way. The offset points out. I Loctite mine on, as well as re-bending the little thin washer.
Voila, you're done!
Thanks.
