99 Tahoe U-joints..again!

I posted not too long ago with the same title, 99 Tahoe U-joints. I say again because I was on the maiden voyage into the city after all the work I had done on this truck, and the rear u-joint came apart after about 50 miles. In replacing the fuel pump I removed the drive shaft and while it was out I thought it was a good idea to replace the u-joints. Learned all about the factory "plastic injection mold" retaining method used by GM and how to deal with that. See '99 Tahoe U-joints' thread. Anyway, the rear u-joint threw a cap and all was crap after that. Here's the thing. In replacing the u-joint on the bench with the help of a vise, a hammer and my son adding squeeze to the vise while applying hammer to vise jaw, the new u-joint was a very tight fit and needed every fraction of an inch to get the clips in. After installed, the new joint was stiff but could be moved. I remembered a comment from another thread that said, "don't forget to grease the new u-joint before you put it back in". So... I greased the front joint, no problem. But made the mistake of greasing the back joint. I should have seen it coming. The 2 caps push off cuz there's nothing holding them yet. Okay, so I push them back down but they want to just slowly push back off because of the grease. I figured I cold hold them together enough to get the saddle clamps on and tightened up so that's what I did. I remember while I was putting it in the first time thinking that I'd better get this thing centered. Now here's my question and I'll have to use the "F" word here. My Ford has a ridge on the outside edge of where the caps sit in the rear pinion yoke so the u-joint is "contained" and centered when tightened. The Tahoe has no ridge and the clamps don't either. I thought sure when I pulled this shaft back down, I would see where I didn't hold the caps together enough to catch the ridges but there is no ridge. How do you know if the shaft is centered? Do you just tighten the crap out of those bolts? I don't want to make the same mistake again.

Without seeing it we can not help much.
First thing to check if cap does not go down enough to get lock in is to pull cap and check for a needle bearing fell down between cap and cross.
Also make sure you have right U joint.
Some are outside locks and some inside.
And some are double joints.
Which have you got?
Vise and hammer is not the best tools for changing joints.
If it comes apart while driving it sometimes can tear up a lot of stuff.
To be on the safe side.
It might be best to take it to machine shop and let them check/install joint for you.

It's embaressing to say but I've done a few u-joints in my day. We're dealing with the rear joint here. The joint I have has a brass C clip that slots in on the inboard side of the shaft lug in a groove in the cap. The question is: Is there a centering ridge in the land of the rear pinion gear yoke. My Ford has a ridge that keeps the caps, (u-joint assy), centered and retained. How do I know when it has "lock in"? When I put it in the first time I thought it was odd not to have a ridge and tried my best to center it then. It's possible that a needle bearing fell and the cap was not all the way down but after it was in, I had about 1/8th inch on either side with the caps recessed to the inside, not sticking out. If I had the wrong u-joint, the fit would have been sloppy for the two legs in the shaft or too long and not allow the clips to engage. I did have alot of trouble getting the clips but they did go. I'm really looking for the answer to the ridge question. If there should be a ridge, and I don't have one, centrifugal force will throw the caps out sooner or later.

They need to be locked in somehow.
Did you look at the old one before removing it?

There should be a flat ridge on the inside or a notch on the outside.

This is a duplicate post, maybe a moderator can merge them?

I have done lots of these, and never noticed anything that actually holds the caps in. The u-joint from the factory has a strap welded between the bolt-on caps. I've never got a replacement that has the strap, and I've never had a problem without it.

I didn't take notice when it came out. I have pics now. Can't upload pics. I tried shrinking down to 48k and it still fails. I'll try again tomorrow. You need to see these pics. If there's another way of getting pics to anyone let me know, I can e-mail them.

I remember the straps now. Damn, I thought I was crazy. So if it's centered thats it?

like mt 2500 said they have a C clip on the inside or the ring on the outer ridge..this needs to be cleaned when the plastic is melted out..

I just did the front u joint on the s10 4wd and these had the inner c clips on the pressed in caps then the other caps had the yoke stubs and straps locking these other caps..

the caps you pressed in should have I would guess the inner c clip..which should pop in to the cap and you should have plenty of room ..if not and with your discription you bent the yoke slightly if it is tight ,,,should not be stiff...hit with hammer easy until the yoke is bent back,,,,use a light weight hammer with the yoke in a vice...

also prior to pressing in the caps use a small piece of fine emery cloth to remove the scores in the inner yoke area where the cap is going to be pressed in ,,that way you will not squeeze the yoke ears too hard and bed the yoke again..

when I did my drive shaft last week it was very easy...but these did not have the plastic,,,just clips but still 1994 oem vintage u joints..

I wish I hadn't doubled up on this thread. Not sure how it happened but I apologise. J-Ri, thanks for chimming in on the other post. You know exactly what I'm up against. When I was looking at the new joint I just bought, I realized there is a groove for an in side clip on all 4 caps. That's when I had the brain storm that the clips may go on all 4 of the rear joint and hold the caps when the straps are on. I've never had to put clips on all 4 rear caps before. Not even on the '87 2WD GMC Jimmie I put the 350 in. Put the new joint on the shaft, no problem, better than before (same part number). Not too stiff either. Put the clips on the caps to the yoke side hoping they would fall between but they didn't. One side dropped in but the other needs a very little bit of room. It's 23F, 25 kt wind and the truck is in the parking lot at work. I'll try backing the shaft off and re-centering it as it goes in. Not very optomistic but it was damn cold. ----Got the chance to get back under and re-try putting the shaft in with clips on the loose caps. It WORKED OUT. Now thinking back, I would almost bet on the idea that a needle bearing dropped in the cap that departed making it stand out further than the other, placing the shaft off center. If I would have put the clips on to start with, the shaft would never go in because of the dropped needle bearing making the whole thing too wide. Just like when you drop a bearing on the press in caps. I just made sure the gap was even on each side before I tightened it up. This would account for the inbalance. I noticed the low hum of an out of balance D/S as soon as I hit about 40MPH but pushed the thought off to new tires since I had replaced the u-joints. It was after about 20 miles and a right turn that it went all at once. That's where I'm at now. It's suppsed to go down to below 10F for a high for next couple days. Probably go out Sunday to get it, what ever I end up doing.
PS I'm sure you guys are looking at both posts and cussing me but I'll try to stay with this one now.
Thanks all!

I've edited the last post above with resolution. It makes for mistakes when you work in sub freezing conditions. Bottom line, put C clips on all caps, front and back.

I've edited the last post above with resolution. It makes for mistakes when you work in sub freezing conditions. Bottom line, put C clips on all caps, front and back.

good post however ...not much on this type of repair...now your ready for the next U joint ....others will learn from this..

like I stated in the earlier posts I used you tube video to see how others did this repair even though I have had to do this many times in the past ..I always look at others technic's to save time / damage / money on any repair...

now just keep them lubed..good luck