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Smokin 79 wheel bearing ?

4740 Views 19 Replies 4 Participants Last post by  PowerWagonPete
So I have this bone stock, low miles, total survivor 79 RC that I picked up a few months back. Did the total lube job thing per the FSM including front axle u-joints and wheel bearings right after I picked it up. Today I pulled in the driveway and the right front corner is smokin like its on fire. Yanked the wheel and the brake disk is a lot hotter than it should be but the brake caliper isn't dragging. The only sign of frying fluids that I can see is around the wheel studs.

Does is seem reasonable / likely / typical that the outer wheel bearing seal went poof and the grease got flung through the access hole in the rotor hub? There doesn't seem to be any fluids drippin or burning off the inside of the rotor or steering knuckle area.

Is the outer seal between the outer  bearing cup and the rotor hub or is it between the bearing retainer and the knuckle or is it somewhere else? btw, have been reading the FSM, how to 35 and the forum archives but still a bit confused.
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bearing inspection: front tire on, grab tire and try to wobble - no noticeable rattle, movement. front tire off, brake disk still smokin hot, channel locks on the axle shaft nut and pry bar between the wheel studs - still no noticeable wobble that felt liked wasted bearings.

grease on the rotor: it really looked to me like grease was seeping out between the hub and the wheel studs. yeah ok, that doesn't seem real possible but that's the best way to describe where I noticed the grease - on the brake rotor hub, outer side, near the wheel studs. couldn't say about the inner side with the dust shield on but again most of the smoke seemed to be coming from the hub face.

Gotta love Chrysler docs: just found that same cross section in my 79 RC FSM in the brake section and it makes it look like the outer seal is in the bearing retainer. A bit earlier I pulled the master parts book diagram and that makes it look like the seal is outside the retainer. Yeah, yeah - rent the hub puller and go lookin.

So anyway, are these things known for tossing seals (or bearings) in a way that the grease ends up the rotor?
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So I went out and scored the big socket and the hub puller and started pullin stuff apart last night. Decided to pull both sides apart so I could stare and compare. Yanked the rotor / hub per FSM rather than rotor / hub / bearing retainer per how to 35. At this point the outer bearing and races on both sides look pretty good, the grease looked fairly brown and the outer seal doesn't look particularly wasted on either side. Gonna de-gunk and yank bearing retainer later. Based on a closer look at the back of the hub and the back of the knuckle it pretty much looks like both innner / outer seals are weaping grease.

Is there a good / affordable tool for yankin the outer bearing / seal off the hub ?? Tried with a generic 2 jaw gear puller but didn't get real far. Same question for putting the bearing back on.

The FSM says put outer seal / bearing / retainer on hub then bold retainer to knuckle. Seems more logical to me to put bearing in retainer, bolt retainer to knuckle, drive hub/rotor in - ya know, reverse the tear down procedure. What's the easy way here ?

How much hassle is gonna be gettin the hub back on the spindle and what tool am I gonna have to buy for that?
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Having gotten no where with trying to pull the outer bearing off the rotor hub I took a trip to the local repair shop and did a bit of rummaging around in thier tool box. The professioanl bearing puller did a fine job of destroying the roller half and managed to yank one cone with a bit of encouragement from a flame. It took the cutting torch to get the other one apart. With any luck I'll have time this week to take the retainer apart and see how much fun the inner bearing is going to be.

I did notice in the FSM where it says to toss the o-ring and replace with silicon. It does apear that these seals were replaced at least once already as I can see the silicon between the retainer and the knuckle.
The saga continues and with any luck will turn in to a one stop thread for the next guy tryin this (have spent last hour or so diggin through the archives for bits and pieces of help), anyhow: Went down this morning, removed bearing retainer, dust sheild, caliper brackets. Put pry bar on axle shaft per FSM and was totally amazed how easy it was to get the outer race, spacer, inner bearing, inner race and cup seal out of the knuckle. Kinda think it's gonna a pain to get the drivers side axle shaft back in the bearing but that's a problem for later.

Per some previous threads and Chumps database, gonna head to AutoZone for the Timken bearing set x2. Was considering recycling the inner bearings and just buying one "kit" and using it for outer bearings as the inners look ok but am thinkin I may as well do the full job as long as it's ripped apart. Also gonna grab a pair of outer seals (timken 413248).

The missing piece in the parts shopping puzzle at this point is the slinger / lip seal / cup seal. There is a thread out there that says toss it and use an outer seal in place of it but that doesn't sould like fun. If going that route - toss all 3 pieces or leave the slinger on the axle shaft ? There's another thread out there that says NAPA sells the lip seal (handy as a least one of mine is split) but when I look up the PN in Chumps db (napa 400700) it comes back as a pinion seal and the pic don't look quite right. Whats the recomendation here and do ya really think I can still get the OEM piece (4036432) from the local Dodge dealer ??
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Oddly enough, this is actually starting to make sense and is a lot less confusing than it sounds. First time doing 4wd wheel bearings (if ya couldn't tell). I almost asked ya to define "fully seated in the knuckle" but I went down and looked at the cup seal / knuckle and then also looked at how to 35 to confirm that the outer / inner seals face in opposite directions just like the bearings. The mental image I'm having of getting the axle seal in is the hassle involved in putting the vibration damper seal in the front cover when doing a timing chain but I suspect this will slide in a lot easier.

Thanx all for all the help and hopefully a final update when I get it all put back together.
PowerWagonPete said:
BTW, this is always a good time to replace the both the axle u-joints and the ball joints. ;D
Yeah, already had that thought. Murphys law clearly states that one of the axle u-joints will go out shortly after getting the bearings back together. For now, just gonna fix what's broken, get on with the pending projects on 2 of the cars, get back to working on the big block transplant prep and hope for the best.
So I finally dragged my butt back down to the garage to put this mess back together today. Started by scraping another 5 lbs or so of grease, gunk and road dirt off the knuckle and that's always alot of fun. Cleaned up the axles, put grease on side gear ends and they slid right in. The outer seal turned around and used as an inner seal looks like it will work great and for those at home keeping track - a short piece of 3" O.D. exhaust pipe works great as a seal driver ($2 at autozone). Put the caliper bracket and dust sheild back on, pack the bearings, bolt on the retainer. All pretty straight forward, easier than ya think it will be and a lot greasier.

PowerWagonPete said:
The hub should slide right back on the spindle through the bearing cones. If not, tap it on far enough for the spindle nut to grab the threads and use that to push the unit together.

Yeah, in this case, it's easier to put these back together than to take apart. LOL ;D
Tap it with what? A jack hammer??? I put a lot of grease on the inside of the hub, likely left the stub axle dry (schmuck) and greased the outside of the hub. Using a little 5 lb sledge I was only able to get the thing seated to the point where the end of the stub axle is just about flush with the front of the hub - at least an inch short of even seeing the threads. Tried the other side, got just as far (or not), quit for the day before cranking up the compressor and getting the air hammer out as that just doesn't sound like a good idea. Just how hard should I be hitting this frickin thing to get it home?
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I was usin the spindle nut socket and a short extension as the driver so cool on that. Really dunno why I was dumb enough to think the thing would slide easily in to the bearings after what I had to do to get the outer bearing off the hub. Power of posative thought I suspect. Will give the jam the axle thing a try later this week.

Hit it not quite hard enough to knock it off the jack stands - good description.
So this morning I managed to get one side knocked on far enough to start threading the nut. A couple of helfpull hints for the next guy:

a block of wood jammed between the bottom lug nut studs and the floor will cut down on the wobble while gettin it started and keep the whole thing from spinning while torqueing it down.

swing the hammer like yer tryin to knock the thing off the jack stands
Finally got the whole thing put back together, took it for a short test drive, noticed maybe some small burning smells. No smoke clouds this time but the passenger side wheel cover was hot to the touch after only 10 miles or so. With the pin type calipers this a dead give away that the brakes are dragging and even though both fronts spin freely (jacked off ground) I decided to replace both calipers. Oddly I had some nearly new used pads handy.

Take another test drive and both fronts were noticeably cooler after same 10-15 miles. Does make me wonder if the brake rotor got hot enough to fail the old seal and/or liquify the old grease. Oh well, at least I have new seals, bearings, calipers, pads and if the axle u-joints stay together for a year it's all good.
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