The Stovebolt Site Forums The Shop Area Engine Shop uni-joint bolts

Just any enquiry guys. A few months ago I replaced the okie bushing and uni-joint on the 41. The truck has done about 3500 miles since. The wee bolts on the uni sheared yesterday ( not impressed ). I was wondering if any others have had similar problems with the replacement bolts available in the uni-joint kits. I've found some original bolts from a spare tranny and will be using those on the rebuild.

Thanks guys

Bob

I've had time to have a closer look and think that what may have happened is that the bolts loosened off. These things were tightened down and I used red loctite on the threads. I also used the retaining tabs. The tabs that came with the uni-joint didn't appear to be as good quality as the original ones and the holes that the bolt goes through were a fair bit bigger than the originals. Again just wondering if any of you guys have had similar problems. Given that these four piddly little bolts play such a critical role should checking these form part of a regular maintenance program? As always thanks folks.

Bob

I had those bolts sheer off on my '50 1/2 ton, and ended up making the joint go cock-eyed and blew out the side of the tranny. I really drove the balls off that truck, tho.. dragging a 4,000 pound car up a hill on it's roof with a stock 216 and a 3 speed probably wasn't what the truck was built to do.. but it did it.

The '46 1/2 ton I just got had the same thing happen to a previous owner.. the u-joint was split when it arrived, with two of the bolts sheered off and the other two missing.

I ended up drilling all four holes out and tapped them for bigger bolts, with a little less fine a thread, cranked 'em in tight with some loc-tite, then folded over the tabs to keep 'em from unscrewing.

My guess on why these joints fail is that one or two of the bolts end up loosning up, making the joint sloppy.. with one bolt out it isn't long before the wobbling ends up working the others loose, or sheering them off.

The red loctite should have held. Most cases of failure occur due to oily or dirty threads. When you put it back together be sure the threads are clean and dry. Run a tap into the threaded holes, I usually clean bolt threads on a wire wheel. Then hose it all down with carb cleaner, making sure all the gunk and oil are out of the holes.

Properly applied, red loctite takes a torch to get apart.

Thanks for the input guys. Point noted about the threads Fred. I don't want to be doing this again for a long time.

All the best

Bob

Update guys,

When the bolts gave way the thrashing around did damage to the front and back yokes and bent the speedo gear shaft. I scrounged these parts from an old box and have put everything back together. I'm still getting bad vibration in top gear in the four speed box. It doesn't seem to vibrate much going through the lower gears. I was wondering if it could have damaged the gearbox rear bearing or gearbox shaft. Any advice would be appreciated as I need to get this back on the road asap. One other point was that when I tightened up the trunnion on the front yoke I had to move the driveshaft over a wee bit to line up the second two bolts. The first two lined up fine.

Thanks folks

Bob

Just bumping this up to the top again folks. I'm going to take the uni-joint off again and start from scratch. Anyone have any other ideas regarding the vibration?

Cheers

Bob

Sounds like major problems in the transmission, either the rear bearing or shaft. I would be swapping the transmission if I had a spare. I have never worked on one of the pre-48 gearboxes, so I can't help you on that.

Thanks Fred,

I don't have a spare tranny thats any good. I'm about to start stripping it back down and I'll then be able to have a look at the gearbox shaft and bearing. With a bit ( lot ) of luck it may just be the bearing.

All the best

Bob

If the problem ends up being a pain to locate, and a direct replacement tranny isn't available, (or available at a reasonable price) you may consider swapping it out for one of those s10 5 speed trannys.

Thanks Fumblin46. I really like this old crash box. It took me a wee while to get the hang of it. I'd hate to swap it out. I'll see what the damage is and report back.

Thanks mate

Bob

Another update guys,

I took off the uni-joint. There is some play in the gearbox shaft. I also took off the ht lead and turned the motor over in top gear with the foot starter. The gearbox shaft seems to turn true. I then jacked up the rear and got my son to turn the back wheel. The main driveshaft seems to be out of true a little. I'll let someone else with a bit more experience have a look at it before I go any further. Another job to add to the list.

Thanks again for the help folks.

Bob