Problem With McGaughy's Drop Spindles on 67 GMC

[fasttech]

I purchased a McGaughy's drop spindle and 13" brake kit (#63148) about a year ago for a disc brake conversion on my 67 GMC. The kit #63148 is supposed to be specifically designed for 60-70 Chevy / GMC trucks. I called McGaughy's a few days ago and they confirmed I have the correct kit and it should just bolt in. I finally had time to start the conversion and now I am having a problem with the spindle working with the upper ball joint. Basically the hole in the upper spindle is slightly larger than the stock drum spindle I took off the truck, and as a result it never seats on the tapered shaft on the upper ball joint. The upper mounting point on the spindle is also a lot thicker (1/2" more) than the stock spindle. The strange part is the stock lower ball joint and tie rod end both appear to work just fine with the McGaughy's spindle.

When I try to torque down the castle nut for the upper ball joint it just keeps going way past the cotter pin hole until the top of the spindle runs into the bottom of the upper control arm. So much for just bolting right in! The stock upper ball joint is 1/2" at the threaded end. The bottom side of the hole in the upper ball joint mounting flange on the new spindle is .56" or 9/16", so it looks like a ball joint with a 9/16" threaded shaft might work. Any one know the threaded shaft size on a 71-72 upper ball joint? I don't have a problem changing the upper ball joints if that is the solution, but no parts stores have these on the shelf anymore that I can try before I buy. It will be a special order or on-line purchase so I want to make sure changing the upper ball joint has a good chance of working.

I am not a fan of McGaughy's stuff so far. What should have taken a couple of days is now turning into weeks!

[Pro Performance]

I had a customer with the same issue with his McGaughys spindle and ball joint fitting. He tried just about every ball joint, but the Moog one worked for him. I am not sure why the Moog would work and the others would not, maybe tolerances in the ball joints and the Moog are built to a tighter tolerances????

Anyhow, he got a Moog from the local auto parts, and this did it. If you can purchase this ball joint without a special order and return if it doesn't work. I have a feeling it might for you, but if not, I would hate to see you stuck with a ball joint you can't use and more money invested.

- Travis

[fasttech]

I was able to solve the problem but it's not a bolt on solution. I ran across some older posts that talked about the machined pad at the top of the mounting hole for the BJ on the new spindle. The entire upper mounting hole section on the McGaughy's spindle is 1/2" thicker than the stock spindle so I broke out the angle grinder and die grinder. I completely ground down the pad sticking up above the main casting on the top BJ mounting surface. This was about 1/4". I then took the die grinder and cut off about 1/4" from the bottom of the upper A-arm. I was able to get everything bolted up correctly after all that grinding and cutting. Certainly not a bolt on solution. McGaughy's engineering and machining is piss poor if their part has a 1/2" deviation from stock. There is no way this can be called a bolt in kit even if you have to go a buy new upper ball joints. I will post some before and after picks that can maybe help someone else out in the future.

FYI - Travis, appreciate your reply. None of my rant was directed at you in any way, just McGaughy's.

[fasttech]

Here are some pics of the modifications.
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[fasttech]

Pics after the mods.
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[CC69Rat]

Mine bolted right up. Moog ball joints. .. same kit.

Bizarre.
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