Half Shaft U-Joints

[76okievette]

OK, I need some help, I have installed my half shafts, 1976 L-48 Auto, with the new spicer jerkless u-joints. The problem is the u-joints don't seem to fit in the flange coming out of the differental. The flange has two cups that the joints slip into and the joint caps fit right in. The other two joint caps, the ones that get the u-bolts over them don't fit between the two small ears, there are just two small ears on the flange coming out of the differental that the joint caps fit between then the u-bolt goes over the top and bolts them down. Well I could not get the U-joint to fit exactly between those two ears. One side is inside of the ear the other is about a sixteenth of inch to long and the joint cap won't seat completely inside of the ear. The U-bolt holds the joint in place and is tourqed correctly I am just concerned that it does not fit in between those two ears/tabs. I had the u-joints installed on the half shafts by a very honest corvette place so I assume they are the correct size. Also when I was installing the half shafts one of the u-joint caps did come off but I reset all the little bearings and but it back on it, seemed to slip right on. Please let me know what you think, do I have to remove the half shafts again or do you thing they are ok?

 

[cwerve74]

Is it possible that one of the needle bearings is between the end of the U-joint and the cap for the u-joint? It would make the assembly too long and not fit.

 

[76okievette]

That was my first thought so I check and I am 99% sure that all the needle bearings are in the correct place. Also its not just one side but I have the exact same sitatuation on both sides. The u-joints seem to fit ever where but between the two ears. My only idea now is to take it to the shop that installed the u-joints in the shafts and have him inspect my installation, that is unless I can get some good ideas here. Thanks

 

[vettenick]

It's just a guess, but maybe you have air trapped under the cup when you packed it with grease. When that happens the caps don't compress all the way down.

 

[GTR1999]

Do I understand you correctly, the 1/2 shaft joints fit into the side axle yokes and caps ok but the pinion yoke doesn't fit around the driveshaft joint? If so the dirveshaf joint is different then the 1/2 shaft joints. Could you post a picture?

 

[brusso]

Not having worked on mine yet so I'm not to sure, But here goes. A spicer means that the u-joint is longer, in one direction, than the other. Is it possible that the vette place put them in backwards or are they so differrent in lengths that that is not possible?

 

[JohnZ]

Sounds like you may have the wrong U-joints; the driveshaft and half-shaft U-joints are different, both in cap diameter and overall cap-to-cap length.

 

[Vettehead Mikey]

A spicer means that the u-joint is longer, in one direction, than the other. Is it possible that the vette place put them in backwards or are they so differrent in lengths that that is not possible?

Not sure what you're driving at, but 'Spicer' is simply the name of the manufacturer. The u-joints for this year Corvette IIRC, are symmetrical in length. If they are not fitting on the diff yoke, it's either the wrong part number joint or a needle bearing is trapped under the cap as others have suggested.

BTW, please don't drive the car till this is fixed!

 

[76okievette]

Thanks for all the input, to clearify this, the u-joint that connects to the Diff yoke does not seem to fit in. I have contacted the shop and he is going to take a look. He told me that it is an extremely tight fit to get the u-joint caps to fit between the ears of the diff yoke. I have attached a picture of the diff yoke and you can see the ears on one side of the half round channel the u-joint fits into. I can't get my joints to slide all the way down in between those ears. One side is all the way on but the other side is only about half way in. I am 99% sure I have all the needle bearing in correctly. I have to drive the car to the shop but I have the u-joints strap bolted down tight so I think i will make it. I will let you all know what happens. I don't take the car in until Friday. I feel pretty stupid that I could not put these half shafts in. I was pretty frustrated with myself the day I was trying to install the shafts, I would have it all layed in and then rotate the shaft to get at a different bolt and the shaft would fall out of the yoke and/or the u-joint cap would slide off the end of the u-joint. Is there any way to attached the caps to the u-joints during installation so that you don't knock them off?

 

[GTR1999]

There should not be a problem with the joint fit into the side yoke. If you have one sid ein and other 1/2 way chances are good theres a needle bearing under the cap. I would not drive the car like this, if the 1/2 shaft becomes disconnected you're in for some fiberglass repair and a flat bed ride.

This is on a 76 right,were joints you used spicer # 5-799x? These are very good if not the best out there but do use a inner preload. There is a black plastic ring on the inner side of the joint-up against the solid cross, This must be compressed slightly-VERY slightly until you heard it snap in place. IF you didn't do this then the cap end to end will be longer then it should and the joint won't fit. BE carefukl not to crack the plastic ring though,you'll hear it snap if you didn't the first time.

 

[6T7Redvette]

This is not that uncommon. Place the half shaft U Joint in a vise and genltly squeeze. It will pop right in with very little effort.

 

[sixty9vette]

Yeah, as stated, you just need to squeeze the cups together. The Spicers are tight and you most likely can't do it with your hands. I use a woodworking clamp with rubber feet (one of those pistol grip looking things) and squeeze away, but a vice will work too. They'll fall right into place after that.

 

[brusso]

Not sure what you're driving at, but 'Spicer' is simply the name of the manufacturer. The u-joints for this year Corvette IIRC, are symmetrical in length. If they are not fitting on the diff yoke, it's either the wrong part number joint or a needle bearing is trapped under the cap as others have suggested.

BTW, please don't drive the car till this is fixed!

That was something that was told to me by my Vo-Tech instructor almost 20 years ago. I guess that I must have taken it out of context. He must have been just referring to a brand of u-joint as opposed to the type of u-joint that was on display. Like they say, I guess that you learn something new every day. Sorry about any confusion and thanks for the redirect.

 

[76okievette]

Thanks for all the data, I believe what happened is that when the cap came off I did not get it seat back all the way. I did not press it in a vice of with a clamp but that sounds exactly like what needs to happen. I will give it a try do you think its possible to press the caps back together with half shaft installed on the car or do I need to completely remove it?

 

[vettenick]

I would take it off just to make sure that it's not binding when you do press the caps together.

 

[wallyknoch]

The U joints for the half shafts are symetrical. Not a combination joint. The correct part number for this application by various companies are as follows, AEC 578, B/W 114-578, GM 609948, Neapco 28053X, Precision 578P, Spicer 5-143X, TRW 20054, and Wesco N1578R. This is for years 71-79. A swapped in differential from another year may be different as 80-83 automatic cars require a different joint. The word Spicer is just a manufacture brand, not that it`s two different sizes. Some custom applications can be solved with a combination joint. {two different size cups and cross lengths} but this should not be necessary in your application if never changed. We sell and install loads of them.

 

[76okievette]

Thanks Wally, I believe I have the correct joints it's just the installation that is not correct. After all the posts and looking at the joints again, I believe I just don't have the cups squeezed down tight. I might be able to do this myself, but since I have reached my frustration level on this job, and I can affort it, i am going to take it back to the corvette shop in the morning and have the job finished up correctly. Thanks again for all you help, I will post tomorrow or saturday and let everyone know what the actual problem was. Again my thanks to everyone I don't think I would have a corvette with out this forum.

 

[76okievette]

And the Rest of the Story, The u-joint replacement on my "76" is finally complete. The problem was just as explained here in the fourm, the caps were not seated all the way. I took the car to the shop that installed the u-joints on the half shafts and he correctly installed them in just minutes with no additional charge. Any of you vette guys that need shop work done and are in Oklahoman City I can highly recommend Dave at the "CORVETTE CLINIC". Thanks again for all your help.

76okievette

 

[GTR1999]

So now you know for the next time. Don't give up on this stuff you can do most of it with some investment in tools.

 

[76okievette]

So right Coupeman and it keeps the frustration level down.