Author Topic: Rebuild the TC Shift Linkage U-Joint  (Read 1425 times)

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Offline 2483R

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Rebuild the TC Shift Linkage U-Joint
« on: Monday,August 03, 2020, 09:12:51 AM »
The TC shift linkage has 2 u-joints, one at the rear of the car and one next to the engine (pic 1). The u-joints can be rebuilt, I rebuilt both of mine a few years ago for about $50 each.

A drawing of the center u-joint is shown in pic 2, with the image taken from the Bean catalog. The rear u-joint is the same as the center. The factory u-joint parts are shown inside the circle in pic 2. These parts are; 4 bearing caps, a square block, 3 shafts (2 short and 1 long) pressed into the square block, and 4 leather washers.

You will need a press to disassemble the old u-joint. Use the press to force one cap in which will push the opposite cap out, then use vice grips to pull the extruding cap completely out. Repeat for the other 3 bearing caps. The yokes are easy to bend, make sure they are well supported when using the press.

If the yokes and the square block are in good shape, the u-joint can be rebuilt.

The bearing caps (pics 3 and 4) are a standard off-the-shelf item. I bought mine from a local bearing supplier for around $5 each. I used a Timken M-661 for the center u-joint and a Koyo M-661 on the rear. Both products are the same. There may be other companies selling similar products as well. The caps come with new needle bearings installed.

The square block (pic 5) is simply a square piece of steel with 2 holes drilled in it. More than likely, the shafts in the square block will be worn. The long shaft goes completely through the square block (pic 4). The 2 short shafts have a circular radius on one end, and the radiused end butts against the long shaft inside the square block.

Use a press to remove the shafts from the square block. The trick is to remove the long shaft first, as the short shafts will not move because the long shaft is in the way. But there is no way to identify the long from the short shafts when they are in the square block. If you apply some force on one shaft and it does not move, then it is the short shaft. Rotate the square block 90 degrees and press on the other shaft.

To replace, you will need a length of 3/8" diameter harden steel rod machined to a high tolerance. I bought mine from McMaster-Carr for about $20 (pic 3), part number 8888K42. Use the old shafts as templates to make new ones. I cut them to length using a thin cutting disk mounted in a bench grinder.

Radius the ends of the short shafts with a grinding wheel mounted in a drill press (pic 6). The grinding wheel has the same diameter as the shafts. Use a small vise to hold the shaft in place while grinding. You will not get machine shop quality with this technique, but it works. The new shafts are shown in pic 4.

It may not be necessary to radius the ends of the short shafts, as a straight cut flat end may suffice. But it is a lot of work to remove/disassemble the shift linkage, and I did not want to do this twice. So I decided to copy the factory and radius the ends of the short shafts.

You will need a slight interference fit between the square block and the shafts. In my case, the shafts I made from the McMaster-Carr steel rod worked fine.

Put a dab of grease in the bearing caps prior to installing. Press the assembly together and use green Loctite on the yokes to help hold the bearing caps in place.

The only drawback is the original u-joint had washers, which I assumed acted as a seal for the bearing caps (pic 2). The washers appeared to be a material similar to leather. My original leather washers were not reusable, and I did not replace them.

The leather washers will deteriorate long before the steel in the bearings and shafts, leaving a gap between bearing cap and square block. This gap will allow dirt/water inside the bearing. So I am not sure how effective the original leather washers were as a seal, and I wonder if I really lost anything.

Ron
2483R







Offline Chuck Nukem

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Re: Rebuild the TC Shift Linkage U-Joint
« Reply #1 on: Monday,August 03, 2020, 10:02:30 AM »
Nicely done!

Offline Grumblebuns

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Re: Rebuild the TC Shift Linkage U-Joint
« Reply #2 on: Monday,August 03, 2020, 10:45:54 AM »
 Outstanding, thanks for the write up.