Quick ??s: Front ubolts, driveshaft u-joints

[Metalhead47]

Ok I know this info is probably here somewhere but I just need a couple quick answers so's I can get parts in by this weekend.

Anyways, 1990 3/4ton 'burb..

Finally started bolting my front axle back in (10b) this weekend, only to discover one U-bolt is an oddball size to the other three . This is what happens when you tear a project apart then don't touch it for two years. Anyone know what size the U-bolt is nearest the pumpkin, pax side, on a 10 bolt? Ubolt plate looks like 4-1/8th or so, but I also see 3-5/8's listed... help?

Also, pulled the front driveshaft for a quick rebuild, and I noticed that the Ujoints on the double-cardan end look like they're pinned in or something as opposed to circlips. Any insight here? Thanx.

 

[gonefishin]

I think but not sure my u joint is a 269 from orieley and if the cv is all factory then you have to burn out the plastic holding the joints in with a torch

 

[Metalhead47]

I think but not sure my u joint is a 269 from orieley and if the cv is all factory then you have to burn out the plastic holding the joints in with a torch

Ahhh so those lil pins are actually plastic? Weird. I'm assuming the ujoints can still be replaced with standard circlip ones right? Could I just stick the whole the whole thing in the oven & burn em out without messing up the temper of the metal?


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[gonefishin]

Yes c clip joints replace them I don't think an oven would work very good I have used a propane torch before it just takes awhile and look at the ball and socket while its apart

 

[496truck]

Yup, more heat than an oven. The plastic will ooze out of that hole like a worm. It's mildly entertaining.

 

[Fordum]

Ahhh so those lil pins are actually plastic? Weird. I'm assuming the ujoints can still be replaced with standard circlip ones right? Could I just stick the whole the whole thing in the oven & burn em out without messing up the temper of the metal?


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The factory lined the u-joints up in a fixture and injected hot plastic in that hole and filled a groove to lock the cap in.

I have seen them pressed out with no heat, but some heat is good. You can put most of the heat on the cross until you see the little plastic pin start to ooze out.
That way you don't heat up the parts you are going to keep as much.


There was a problem with replacing them several years ago. Since they did not use the clips, the machining for them was not as accurate as it should be.
The fixture made sure the cross was centered in the shaft. When you went to replace them with clips, the joint would sometimes be off center, causing all kinds of vibrations.

Haven't seen that lately though.

 

[Metalhead47]

Thanx for the info guys. Yeah I think the oven would be a bad idear. Did some googling of my own after gonefishin revealed the pins are plastic (was too pissed last nite to notice myself, discovered that four years ago when the stealership replaced the tranny they never bothered to hook the rear support brace back up), and read that the bearing caps have been known to go thru walls when heated. My rental agency generally frowns on putting holes THRU the wall.

Re the bad machining, is that something I could take the chunk to a driveshaft shop & have it checked? Any idea what the model year cutoff is on those?

And how bout the odd ubolt?


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[ChevyBoy2010]

Its a U-joint... Just replace it and go!

 

[Fordum]

Re the bad machining, is that something I could take the chunk to a driveshaft shop & have it checked? Any idea what the model year cutoff is on those?

Not sure of any year numbers. I've got a friend who runs a machine shop and does a lot of driveshafts.
He's got a balancer which a lot of shops don't.

Not too long after they went to the plastic injection system, he started seeing a lot of vehicles coming into his shop with bad vibrations after the customer replaced the joints.
He took the clips off, and squared one up in the lathe. He discovered that when it was true, the clip went on one side with space and the groove was inside the ring on the other side and you could not put the clip on.

He changed the yoke, and that fixed it. He figured that the customer had bent it trying to press out the plastic.

He was starting to change his mind after a few more came in, when someone brought one in to be changed.
Before he changed it, he measured and found that one side had more metal machined off than the other.
The total distance between flats was correct and the clips would go on just fine, but the cross would be offset.

I'm guessing that they must have done something about it, because I don't see many like that anymore.
For a while he was making good money cutting off and welding new yokes.

But, a couple of years ago, I ran into another one, so some of them are still out there.

A good driveshaft shop could cut off the bad yoke and weld on a new one plus balance it.
I suspect the odds are that you will not have a problem. I just wanted to let you know in case you picked up a bad vibration so you would know what to check.

 

[rick88blaze]

read that the bearing caps have been known to go thru walls when heated.

I will vouch for this. I've had a couple shoot off at least 15 feet when I was changing u-joints. I was using a propane torch to melt the plastic out. One actually shot from the back wall of my garage out to the driveway at my old house. The garage was 20 feet deep.

 

[dremu]

Finally started bolting my front axle back in (10b) this weekend, only to discover one U-bolt is an oddball size to the other three . This is what happens when you tear a project apart then don't touch it for two years. Anyone know what size the U-bolt is nearest the pumpkin, pax side, on a 10 bolt? Ubolt plate looks like 4-1/8th or so, but I also see 3-5/8's listed... help?

10B's and D44's are like that, cuz one goes onto the pumpkin, not the tube. Yeah, it's annoying.

Three are 3" and one is 3-5/8".

Be careful to check for length, as that last one must also be longer to go around the pumpkin. If you have thick springs or a zero-rate/EZ-inch, the typical 10" long U-bolt is too short.

-- A

 

[496truck]

ORD has u-bolt kits that have all the proper size u-bolts in them.

 

[Metalhead47]

Thanx for the info guys. Don't need the whole kit, just the oddball ubolt that's now on its way. Wanted to upgrade to 5/8ths bolts while I was at it, not sure what size ORD's are.

Guess I'll wait till I get the driveshaft torn apart before I order new parts there. It's actually in phenomenal shape consider its got a quarter of a million miles on the original factory build. If the machining's off, would it be pretty obvious or do I need measuring tools? Looks like the center "chunk" that holds the double u joint is inexpensive, might just replace it anyway.


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