Help: Various Related to axle U Joints

XJBucko · Mar 8, 2011

I'm replacing the U joints (as well as a bunch of other stuff) on the front end of my 89 LTD. I've run into a couple of 'issues' that I hope someone can offer some advice on:

One of the hub bolts was completely seized in the hub. Using an impact driver, the bolt head eventually stripped and I had to cut the head off with a combination of a hack saw and a Dremmal (there's 4 hours of my life I'll never get back). So, I need a new bolt and should probably replace the other two wile I'm in there. Are these bolts commonly available or do I have the get them from Jeep?

The brake backing plate (not sure that's what it's called - the thin stamped metal peice that basically protects the inboard side of the disk), are quite rusty and should probably be replaced - are the plates commonly available or do I have to go to Jeep for those?

Shouldn't the axle shafts have a rubber plug or grommet that helps keep junk from collecting in the axle tubes? Pictures of axle shafts that I see have the grommets, but mine don't. Can they be added?

The U joints are really rusted in the axle shafts solid. No amount of whacking (with an appropriate sized socket underneath) seem to be budging them at all. Any tips out there on how to make this easier? Will a U joint removal tool work on a really rusted U joint? Will application of heat work? Worst case, I might be able to get a thin grinding wheel in there and cut the ends off the joint (it'd be tricky though).

Is there a trick to putting the axle shafts back in the tubes without the splines picking up a load of crap from inside the tube?

Aside from lots of surface rust, the hubs seem fine. The bearings spin smoothly and appear to have plenty of grease. They've been replaced, a few years ago now, but not many miles ago. Should I just reuse them or is it crazy to have them off and not replace them?

Thanks for any advice.

the_weirdo · Mar 8, 2011

XJBucko said:
I'm replacing the U joints (as well as a bunch of other stuff) on the front end of my 89 LTD. I've run into a couple of 'issues' that I hope someone can offer some advice on:

One of the hub bolts was completely seized in the hub. Using an impact driver, the bolt head eventually stripped and I had to cut the head off with a combination of a hack saw and a Dremmal (there's 4 hours of my life I'll never get back). So, I need a new bolt and should probably replace the other two wile I'm in there. Are these bolts commonly available or do I have the get them from Jeep?

The brake backing plate (not sure that's what it's called - the thin stamped metal peice that basically protects the inboard side of the disk), are quite rusty and should probably be replaced - are the plates commonly available or do I have to go to Jeep for those?

Shouldn't the axle shafts have a rubber plug or grommet that helps keep junk from collecting in the axle tubes? Pictures of axle shafts that I see have the grommets, but mine don't. Can they be added?

The U joints are really rusted in the axle shafts solid. No amount of whacking (with an appropriate sized socket underneath) seem to be budging them at all. Any tips out there on how to make this easier? Will a U joint removal tool work on a really rusted U joint? Will application of heat work? Worst case, I might be able to get a thin grinding wheel in there and cut the ends off the joint (it'd be tricky though).

Is there a trick to putting the axle shafts back in the tubes without the splines picking up a load of crap from inside the tube?

Aside from lots of surface rust, the hubs seem fine. The bearings spin smoothly and appear to have plenty of grease. They've been replaced, a few years ago now, but not many miles ago. Should I just reuse them or is it crazy to have them off and not replace them?

Thanks for any advice.

a) You can use regular bolts or dealer bolts for the 3 bolts that hold in the hub. Always use anti-seize on these bolts to prevent them from rusting in place.
b) The brake dust shield is probably a dealer only item.
c) You don't NEED to have axle seals. The stock plastic ones do very little to keep junk out of the tubes. You can buy aftermarket ones if you really want to have them.
d) I find that a press makes easier work than hammering them out. A balljoint or ujoint press might also work well.
e) I don't know of any trick to get the axles in without getting junk on them. You can try to swab out the axle tubes before you install the shafts.
f) Reuse the unit bearings unless they are sloppy.

5-90 · Mar 8, 2011

1) M8-1.25 thread, match length underhead. I don't recall just how necessary the reduced head is (since they're flanged anyhow...) but I'd probably replace them with socket head capscrews. If you use never-seez on the threads, install to 37-38 pound-feet instead of 75.

2) You can strip and repaint these with only a little effort. They're just crud shields to keep things from whacking the backside of the rotors. (And yes, "backing plates" is exactly what they are.)

3) Not OEM. They can be had in the aftermarket, but I don't recall suppliers offhand. Or, with some work, you can probably fabricate something. There is sometimes a plastic "splash guard" around the shaft, but it's of dubious utility. I usually end up removing it, since it's often chewed up anyhow. See point four for cleaning.

3) A good U-joint screw press (or a large bench vise) will serve. I've dealt with "seriously rusty" joints before. If you decide to try heat, you want to apply it to the yoke ear only (insofar as possible) while the U-joint itself is under removal stress - this will encourage it to break loose. Make sure the circlips are out (as I recall, those are external. I could be wrong - but they need to be out anyhow...) Also, you can put never-seez on the caps of the new joint - this makes installation a bit easier, and makes removal the next time far easier!

4) Do what I did - get a longish (about 4") piece of flat bar stock about an inch and a half wide, and bend the end at a right angle to give a "toe" about 1.5" long. Grind it close to the inside curve of the axle tube. Use it to pull crud out of the tubes, then wrap a rag around it for a last pull; keep the rag UP going in, then push it DOWN when you pull it out. Solvent is optional but recommended.

If the bearings run smooth & true and are getting lubrication, there's no need to replace them. stet

Matthew Currie · Mar 8, 2011

If possible you might find bolts at a junkyard, since they usually just take the hubs off and drop the bolts. The OEM bolts are necked down where they go through the knuckle, and this is pretty important to prevent them from seizing solid more often. If you use regular bolts, grease or anti-seize them very liberally for their whole length. If one of those bolts rusts solidly into the knuckle, you may have to burn it out with a torch, millimeter by millimeter. Done this, and the hours you've lost dremeling off that head will pale by comparison.

The axle shafts should have had a disk on them, but not a true seal. It will keep rocks and small children out, but not dirt. I think the older ones had a metal disk pressed on, while later ones have a plastic one which snaps together.

If you have the plastic ones, they tend to break, but you can drill the snaps out and put them back together with a wire tie.

The circlips on the axle u-joints are internal, and can be very hard to get out, especially if they're rusted in. It takes patience to find the ends and hit them just right. If one breaks, make sure you get all the pieces, because even a little will stop you dead.

XJBucko · Mar 10, 2011

Matthew Currie said:
The axle shafts should have had a disk on them, but not a true seal. It will keep rocks and small children out, but not dirt. I think the older ones had a metal disk pressed on, while later ones have a plastic one which snaps together.

Thanks for the info guys. Any idea where I can find those snap together replacement 'disks'? I've looked all over and can't find anything.

oldmantompkins · Mar 10, 2011

I used a ball joint press on mine. But be careful mine broke the top of the cap off and shot across the garage with a lot of force. Wouldent have been able to get the joints out without the ball joint press.

XJBucko · Mar 10, 2011

Well, I've got one U joint apart. What a pain! It was impossible to remove the retaining clips - they had transmuted (or something) and had fused the U joint to the yokes. I ended up having to cut the the 4 ears off the U joint with a grinder, then whacking the left over caps out of the yokes. Hopefully the other side will be easier (not that it was particularly difficult, it just took a lot of time).

Matthew Currie · Mar 10, 2011

Those clips do seem to fuse together, but if you can get a longish, thin drift punch to engage the end of one, you can sometimes jar it enough to pop the rust bond apart. It's still a PITA to get it off, but at least it can be distinguished.

1990JEEPXJ · Mar 11, 2011

that is the exact reason why i took my axle shafts to a driveshaft shop to do my u-joints. they only did it for like $20. well worth it for the amount of work it is to change these old u-joints.

Help: Various Related to axle U Joints

XJBucko

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the_weirdo

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5-90

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Matthew Currie

NAXJA Member #760

XJBucko

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oldmantompkins

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XJBucko

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Matthew Currie

NAXJA Member #760

1990JEEPXJ

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