Rear wheel bearing -- help me "see" this

[n2audio]

Hi - '03 Aviator. Lots of miles. I have a "humming" noise in the right rear at 20+.
I'm planning to replace the wheel bearing this week.
I've got a considerable amt of experience with home wrenching, there aren't many tasks I don't take care of myself, but I haven't done a rear wheel bearing on a RWD, well, technically AWD.

I've looked at the sticky and other "how-to" sources. I'm aware the bearing has to be pressed out of -- something? Out of the knuckle? Off the hub? Out of the hub? Both?
I THINK the bearing presses onto the hub, and the hub/bearing assy press INTO the knuckle. If I'm lost, please help.

As for parts...

There are several options that include the hub AND the bearing - Locally looks like around $80 generic, $120 moog. The hub is just machined steel, right? Unless it's broken or corroded excessively there's nothing to replace from what I can tell. So it makes sense to just buy the bearing, right?

The bearing by itself - I can get the National brand locally for around $40.

A couple shops locally are estimating $40 for the presswork.
One shop mentioned seals that may need to be replaced. I saw no mention of seals in the how-to sticky.

I need to get this straight in my brain before I tear into it. Disassembling Thursday night, machine shop Fri morn, reassembling ASAP and hitting the road for the in-laws Fri afternoon. So obviously, very little time for my usual screw ups.

Sorry so long. Thanks in advance for any help.

 

[tower]

I've looked at the sticky and other "how-to" sources. I'm aware the bearing has to be pressed out of -- something? Out of the knuckle? Off the hub? Out of the hub? Both? Both
I THINK the bearing presses onto the hub, and the hub/bearing assy press INTO the knuckle. Correct

I would only recommend TIMKEN for the bearing I have used others and had to redo them later on. Get the hub too as it may be worn but look fine and a worn hub will wear out the bearing just that much faster.

 

[SyberTiger]

I've looked at the sticky and other "how-to" sources. I'm aware the bearing has to be pressed out of -- something? Out of the knuckle? Off the hub? Out of the hub? Both?
I THINK the bearing presses onto the hub, and the hub/bearing assy press INTO the knuckle. If I'm lost, please help.

Based on your questions I can tell you have NOT read the entire thread on changing rear wheel bearings.

 

[n2audio]

I read the "how-to" portion of the thread.
I found a better explanation of way the parts are assembled on a later page.
Looks like the biggest concern is rust.
From what I've seen to this point, ours is as rust-free as a 10 yr old SUV gets so I'm hoping for the best.

I don't plan to replace the hub unless I don't like what I see.
I may buy it, just so I have it on hand. See how the old one looks -- see what the machinist thinks. I just don't see a wear factor with that part.

 

[jav1]

I just did this and I have not found a complete picture online. It's not a fun job and even though I have a full shop (including a 40 ton press), I still had to make up some special tools to get this done. Sorry this is long without pictures.

A breif description of how the assembly works. There are 3 main peices- 1) the cast knuckle, 2) the bearing and 3) the hub (which carriers the wheel studs).

The bearing presses into the knuckle from the backside (from vehicle centerline towrds the outside) and then gets a safety retaining clip on the backside.

The hub presses into the bearing inner race from the outside towards the vehicle centerline- the stub axel and nut keep the hub from pulling out while driving .


To dis-assemble- the knuckle assembly has to be off the car and e-brake assembly removed. The first step is to press the hub off from the bearings inner race from the backside (hub slides out away from e-brake shoes. This requires A LOT of force which must be supported (counter-force) at the knuckle casting. The problem is- the knuckle casting is shrouded by the hub flange and brake dust sheild. You can't remove the dust shield (unless you cut it off) and to get behind the hub flange with bars to resist the press force, the bars have to be about 1" square to not conflict with the knuckles caliper mounting arms. *** NOTE- on you-tube, theres a video of a guy using a puller to remove the hub and the puller uses arms that push on the e-brake shoes to generate the seperating force for the hub to bearing joint- I didn't like this because the shoes get destroyed but more importantly, the shoes don't rest on the casting- they rest on these raised lands on the dust shield. I would presume pushing on the shoes would crush these lands and alter the shoes resting position on re-assembly.


Once the hub is off- and the bearing retaining ring is off- the bearing must be pressed out of the knuckel from the hub side towards the backside. Again lots of force (close to 20 tons) to break the bearing looose and this requires good support and a large socket to push on the bearing.

Care must be taken on re-assembly to not damage the new bearings! When you press the bearing onto the knuckel- you can only apply press force to the OUTER race! If you push in the inner race- you run the risk of damaging the bearing.

When you press the hub onto the new bearing- you have to support the bearing by the INNER race! if you try to press the hub on by supporting the knuckle or outer race- you can damage the new bearing.

Hope that helps someone.

 

[n2audio]

Thanks Jav,
I think I have a pretty clear picture of what needs to be done.
The press work will be in the hands of the machinist, so hopefully that's not an issue.

Given the history of the way most of my projects go I'll find there's a lot more work in the disassembly than what I expect.

 

[n2audio]

It's apart. Wasn't horrible, but wasn't easy. Toe link took SOME effort. UBJ took quite a bit. Axle splines didn't exactly cooperate coming out of the hub either.

E-brake shoes are completely useless. Unfortunately don't have time to deal with that right now.

 

[n2audio]

The good news is I got the bearing replaced w/o much difficulty.
The bad news is the noise from the back of the truck that prompted this job hasn't improved.

The LCA and toe link stud were both rusted in place pretty solid. They took a lot of beating with a 4 lb dead blow, and a few more with a carefully placed large punch and hammer, but eventually I was able to work them loose.
The studs were rusted and pitted so I used a wire wheel to clean them up a bit, and a lot of anti-seize on reassembly.

The parking brake shoe friction material had debonded - so I replaced those as well. Actually, the machinist that did the press-work did the replacing. The total bill was $48.