Front Hub Bearing Replacement--WORDS TO THE WISE - JeepForum.com
 
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post #1 of 5 Old 04-28-2017, 02:43 PM Thread Starter
michla
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Front Hub Bearing Replacement--WORDS TO THE WISE

Don't be like me !!
I'm working on an 89 XJ Laredo and here in Alaska, well over 75 percent of the year is wet in one form or the other. Busting corrosion is my BIGGEST job by far when it comes time to replace parts.

And so it goes...the front hubs were about to give up the ghost @ 230K+ miles so it was time to get them off. But the step-bore in steering knuckle is an interference-fit on purpose for positive location, except the corrosion on just about any XJ this old means you're going to be banging on it to work the hub out. Yeah--just make sure you've removed the 3 bolts on the backside and didn't miss one, etc etc but my corrosion was so bad, nothing could push the old hub out--not even a zip gun (air hammer) hitting the side of the hub mounting ear in the axial plane to rotate and break the corrosion lock. (Have to be careful with heat because those parts are heat-treated) It wasn't until I got the idea to find a longer "dummy" bolt that stuck far enough out the backside of the knuckle to bang on that alternating between the 3 mounting ears to work that puppy out. A puller at the outside helps to maintain positive force as well but you can't tighten that too much pushing on the axle because you're stressing the outboard axle u-joints (make certain knuckle isn't turned at all when doing this) and carrier bearings at the differential.

Nothing I did stressed the axle so much that it should have happened, but seals do become very brittle with that much age and thus very fragile. And so it goes...the banging to bust the corrosion loose was just enough to cause the INNER FRONT AXLE SEAL to fail (gear lube leak outboard) so now I have to disassemble the front again this time changing out the front axle seals too--a big job.

MORAL OF THE STORY: if you can't get the front hubs pushed out, only hit a dummy bolt threaded into the mounting ears from the backside with the proper 10 X 1.50mm thread alternating around all three mounting ears to work a little at a time. If you use a zip gun like I did, the excessive vibration on old already-brittle seals might be enough to kill the inner seals and have you doing the work I am now !!

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post #2 of 5 Old 04-28-2017, 03:51 PM
bluejunior
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For what it's worth, I have a 12 point socket specifically for this. I undo the shaft nut (this limits the amount of vibration transferred to the seal), back each of the three bolts off until I can see 3osh threads and then alternate between each bolt with a shop hammer, beating the socket rather than directly hitting the bolt. I finish loosening the bolts once that interference fit is loose. Be careful to support the axle shaft so that it does not damage the seals by putting weight on them before completely removing the hub.

Lifted, Locked, Stiffened

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post #3 of 5 Old 04-28-2017, 08:16 PM Thread Starter
michla
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Quote:
Originally Posted by bluejunior View Post
For what it's worth, I have a 12 point socket specifically for this. I undo the shaft nut (this limits the amount of vibration transferred to the seal), back each of the three bolts off until I can see 3osh threads and then alternate between each bolt with a shop hammer, beating the socket rather than directly hitting the bolt. I finish loosening the bolts once that interference fit is loose. Be careful to support the axle shaft so that it does not damage the seals by putting weight on them before completely removing the hub.
Very good point about removing large nut.....so many want to remove the hub with the stub axle, but if you're banging on bolt to work the hub out the vibration down the shaft could be an issue for the seals too. I had my large nut removed but it didn't matter--using a zip gun set up enough vibration I suppose for already-tired and brittle seals.

I'm about to start teardown again-I'll see if I can post some photos of the left side seal that is damaged
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post #4 of 5 Old 04-29-2017, 11:04 PM Thread Starter
michla
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Well, got the seals out after spreading the diff to get the carrier out.. no way was it easy to get the diff by prying it out like on the Youtube videos !! Dream on...good thing I bought a spreader a year ago expecting someday I'd be busting a Dana axle apart for repairing.

Reason for my leak was a left side seal with NO lip ! It had worn down completely. I expected the lip to be broken off from my previous post but not so. Just wear and the struggle to get the bearing hubs off started a leak past the seal that wouldn't quit. The axle journal is fine. Onward....
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post #5 of 5 Old 05-01-2017, 12:50 PM Thread Starter
michla
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Ok so the job is done. I had NO idea getting the right side vacuum disconnect seal was going to be such a bear to get in---I struggled quite a bit with that one--even wrecked one new seal on my first attempt using the threaded puller idea.

Looking back on the this job (lacking the proper tool that have fixtures for the seal and the bore is unobtanium nowadays anyway) the ONLY way to get the seals in properly and fully seated is to START them in with the threaded rod puller but then using an appropriate larger diameter socket at the opposite end with several long extenstion bars and whacking it carefully from opposing axle tube ends is the only way to drive them (like you see on YouTube). These seals are a SUPER tight fit and using the threaded rod pulling method without the fixtures that clamp the seal and fix against the bore almost guarantees cocking the seal the farther you pull it in Once started with the threaded rod to get it to stay in the bore, driving it with the socket is the only way to ensure it will go quickly and decisively into the seat.

Working on the right side in the vacuum disconnect box, the opening you have to wrangle tools in there to like 4 inches wide so its critical to have a larger diameter, short socket. In my case I had a 1.5 inch socket about 3.25 inches tall which barely fit. Made sense to use the threaded rod trick given such a narrow opening but kept cocking the seal over and over and over so after wrecking one good $12 one, decided I had nothing to loose by whacking it in from the outboard end of the left axle tube all the way through the diff and right side needle bearing with several long socket extensions. Used 2.25 diameter washer (thick) as backup against the seal OD edge--this size washer just fits inside the shoulder bore--and a few good whacks with a heavy mallet sent 'er home.
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