ok, the machine shop said that they are sealed bearings and I should replace them. The reasoning he gave was that the axle lube will deteriorate the bearing grease and cause the to dry out and die. Is this true? The bearings aren't the cheapest part of the job, so I was hoping to avoid replacing them. Should I just bite the bullet and replace them anyway?

Has anybody done the rear axle seals and not changed the bearings?
I've read the writeups and it sounds ike most people just replace the inner seals. I'm doing both and I have found minimal info about the bearings. Any help is appreciated.

 

could be worth doing, depends on the mileage, which is...?
(still) sealed bearings should be fine for many many miles

 

oops, my bad. My mileage is about 93K.

 

If the inner seal leaked and let gear oil get to the wheel bearing and oil was leaking through the bearing seals, then yes, the bearing grease has likely been washed out (BTDT). If no oil has gotten to the bearing, then it is up to you on replacement. Should run 200K pretty easily on the wheel bearings. If it feels tight, then keep it in there. You are trading off the cost of the bearing vs. a future cost of the bearing plus the labor to change it (which you are already paying for with the seal R&R).

 

Lets see....the arguement is that the diff oil has washed the grease out of a SEALED bearing? This is a new use of the word 'sealed' which I am previously unfamiliar.

Replace the bearing when its worn. Mine lasted 160K miles, and two or three axle seals.

 

just bite the bullet and replace it.

 

Well, seals are not perfect. There are two axle seals and two bearing seals in play here. Gear oil is inside the axle housing. There is the seal where the axle shaft leaves the housing. If it fails, oil can get past it. If the o-ring that seals the axle to the housung fails, you get oil leaking oil leaking out between the housing and the brake backing plate, no real harm done. Next in line are the seals on the wheel bearing. If oil works its way past the bearing seals (they are no different than the seal on the axle shaft, a rubber lip attached to the outside of the bearing that rides on the inner race to keep grease in), then oil mixes with the grease, thinning it. The thinned grease/oil mix can work its way past the other bearing seal and ultimately through the outer axle seal where it leaks out inside the rear brakes. If you have oil leaking there and it has been leaking for a reasonable amount of time, that oil must be coming through the wheel bearing. And along with the leaking oil, there must be some of the wheel bearing grease. I have seen it happen and have replaced bearings because of it.

 

i will second rogers posting, it happened exactly that way on my 93. when we got the bearing off the axle, there was NO grease what so ever left in the bearing, the seals were gone as well. ive done both of mine, at different times. the drivers side was a piece of cake but the pass side had to be cut off. no amount of pounding on 1" plywood would budge the bearing. my hands were aching for several days afterwards.

lee

 

The outer seal is nothing but a dust seal, not intended to keep in fluid. The bearing does not make a good seal to the axle housing, nor to the hub. Diff fluid leaks from the inner seal, goes between the bearing and the axle housing and hub and on out.

 

is the bearing pressed on?

 

Yes:
- http://www.4x4wire.com/toyota/mainte...axle/oil_seal/

 

Once the inner seal (axle housing and axle shaft) leaks, oil start going through the sealed bearing on the axle shaft washing out the thick grease. If you replace the axle seal, the bearing will no longer have sufficent lubrication and will prematurely fail. Now if there isn't too much play in the bearing, you can simply re-pack them. I used a small nail head to pry off the seal on the bearing, then use a thick moly bearing grease, pack in as much as possible and re-install the seal.

 

drive it til the wheels fall off