Front Wheel Bearing "practice" - 1996 Legacy

[JPX]

A couple of weeks ago I finally got around to replacing a CV/axle assembly on the front left wheel. The boot had been split for many months and I could hear the clicking/popping of the joint.

 

That roll pin is a bit of a pain in the neck. But once it was out, everything else was pretty easy. What I found was a wheel bearing also starting to go. I didn't change it on the spot since I needed to get the car back together for the week.

 

I have had a shop press a rear wheel bearing for me many years ago when I did an axle change. And a repair shop did the front bearings several years ago - which might explain why I currently have a bad front bearing. - idiot them for a poor job and idiot me for having them do it at all.

 

I thought I would try my hand at a home bearing change - armed with none other than the Snap-Off tools brand Harbor Freight FWD bearing puller kit.

 

To start with, I picked up a hub/knuckle assembly from the junkyard during the 50% off Memorial Day weekend sale. I figured I could practice on this unit without downing the actual car. The donor vehicle was a 92 Legacy sedan with 168K miles - RIP.

 

 

The only problem was the HF kit does not include a hub puller. The challenge of using an

is that the ABS tone ring is in the way. I wanted to simulate doing the work on the car to avoid realignment - but I am aware that I may ultimately have to take the knuckle off the car.

 

So I picked up a slide hammer from AutoZone under the free loan-a-tool deal. The claw puller attachment turned out to be worthless. It doesn't fit the stud pattern on the hub.

 

 

I got around this by using the washers from the HF kit on the end of the slide hammer to get behind the hub.

 

 

A couple of easy whacks and the hub popped right out. The outer rollers and the inner race came out with the hub as expected.

 

The real fun is yet to come - getting the outer race out of the knuckle/housing.

[GeneralDisorder]

A large socket and a hammer will knock the hub free from the back side. And yes it works on the car also.

 

About 20% of the time the inner bearing cone has spun on the hub. Creating a ridge that makes it REALLY freakin tough to drag the race over. Beating on those type failures is generally futile unless you have a huge hammer. Need a hub tamer/hub grappler etc, or a press to dissasemble them.

 

GD

[idosubaru]

JPX RULES!!!! thanks a bunch for a write up, this is fantastic! I want to start doing bearings but haven't had the time to look into which tools and extra washers, etc are needed for the job.

 

Now my wife's daily driver is down with a bad front wheel bearing so I need to figure this out, great timing!

[unibrook]

I would additionally recommend using the slide hammer to yank the outer race out of the knuckle too, rather than try to press it out with the HubShark/HF tool. The reason is that the friction fit of the outer race in the knuckle is SO FRIKKIN tight that you can easily deform the outer lip of the knuckle with the plates of the tool as you crank on it.

 

Ask me how I know this.

 

[JPX]

I would additionally recommend using the slide hammer to yank the outer race out of the knuckle too...........

 

Ask me how I know this.

 

This is an important idea. I have tried to crank on the outer race from the knuckle with the HF kit. The forces involved are ENORMOUS and I am using BIG wrenches to turn the puller bolt.

 

I tried beating on the outer race with one of the HF plates and a hammer. It is not apparent to me that this type of pounding is going to work - even with a slide hammer. On car might provide better attack angle. But with the practice knuckle not attached to anything, it is hard to apply hardcore slide hammer action.

 

Have you actually been able to get the outer race out with the slide hammer? If so, then I'll give it a go.

[unibrook]

This is an important idea. I have tried to crank on the outer race from the knuckle with the HF kit. The forces involved are ENORMOUS and I am using BIG wrenches to turn the puller bolt.

 

I tried beating on the outer race with one of the HF plates and a hammer. It is not apparent to me that this type of pounding is going to work - even with a slide hammer. On car might provide better attack angle. But with the practice knuckle not attached to anything, it is hard to apply hardcore slide hammer action.

 

Have you actually been able to get the outer race out with the slide hammer? If so, then I'll give it a go.

 

Right, with the knuckle ON the car.....holding it in place, you will be able to pound it out with the slide hammer. It might take 40 or 50 big whacks, but it will come out.

I have only done rear bearings, which exit away from the differential. Front bearings exit towards the engine, iirc, so that might hinder use of the slide hammer, I dunno.

Edited June 1, 2012 by unibrook

[CNY_Dave]

I would additionally recommend using the slide hammer to yank the outer race out of the knuckle too, rather than try to press it out with the HubShark/HF tool. The reason is that the friction fit of the outer race in the knuckle is SO FRIKKIN tight that you can easily deform the outer lip of the knuckle with the plates of the tool as you crank on it.

 

Ask me how I know this.

 

 

When I pressed mine out I was very careful to give the area just outside the race good evenly-distributed support, after seeing how hard I was to press it out

 

a) I have wondered if even the real $300 OTC tool could handle the task for one stuck in tight

 

yeah, you could bend the knuckle if you can't support it evenly.

[JPX]

Well, I started pounding the right direction *doh* on the bearing.:-p

The correct drive is from the outside of the knuckle to the inside.

 

I managed to get the bearing moved about a 1/8th of an inch after HEAVY blows with the bearing plate and a carpenter's hammer.

Yes - I can see why the hydraulic press is superior. I haven't given up hope on this rather stubborn method. But I am second-guessing if I want to replicate this on the car. I'm worried the forces involved could mess up the balljoint, tie-rod end and/or the strut mount if I beat on the real knuckle.

 

For the sake of completeness, I'll try to continue with the practice hub until the out race is out:drunk:......just to say I did it (albeit perhaps badly).:-\

Edited June 3, 2012 by JPX

[JPX]

Well, I decided that hand wrenches weren't going to cut it.

 

Superior Air Support was called in.....

 

 

And after MANY catch-up cycles on my tiny 6 gallon compressor + 4 gallon slave tank......My impact wrench was able to beat that bearing out of the knuckle.

[JPX]

Next up was the hub and the inner race. This was easy with an flat blade air chisel.....I chose this attack angle to avoid damaging the ABS tone ring.

 

This worked okay on the vise until I got to the end of the hub. Then I had to take it off the vise and do it on the floor. But then after beating on the same spot of the race, it broke off a piece......thank goodness for safety glasses!

 

Edited June 3, 2012 by JPX

[JPX]

Well, today I brought the car into the garage for the live fire wheel bearing change....

 

Everything went pretty smoothly preparing the area by removing the CV/axle and the brake caliper from the knuckle/hub.

Then I set up the slide hammer and washers for pulling the hub.

 

That thing refuses to come out. It only took 4-5 hits on the practice hub to get it off the knuckle. The hub on the car has been railed on with 50+ hits and even some air chisel action (blanked off with a bearing plate to protect the spline area).

 

 

Stuck. Damn. Ran out of time this afternoon to get any further on it.

 

But at least I know I am doing a repair worth doing. This is what the bearing sounds like (video).

 

[JPX]

I tried to beat on the hub with the slide hammer again and finally had to make the tough call - it was time to abandon the knuckle/hub assembly. I was mad enough to remove it all from the car and take an air chisel to the backside of the hub. I was quite surprised that my air chisel blade became dead blunt and that the hub was STILL stuck in the knuckle.

This isn't turning out at all like the plan. My conclusion with the original knuckle/hub is that the bearing damage is extensive enough to expect that the hub is heavily damaged. This would explain why it is so difficult to remove.

 

That meant the practice parts are now THE actual replacement parts. Good thing I didn't mangle them during practice. At minimum I would need the hub - but the knuckle was also necessary now.

 

Amazing that the 92 Legacy practice knuckle/hub is identical to my 96. It cleaned up pretty nice too with a wire brush and some WD-40.

 

I started with pressing in the new bearing using the old outer race. It went in crazy easy with the Harbor Freight kit. Just a big wrench and a bunch of turns and the bearing went in nice and smooth.

 

I cleaned up the junkyard hub and lightly polished the shaft with a diamond-abrasive lapping film (15micron) from a friend's lab. I also made sure to insert the snap ring - which is a great indicator if the bearing is indeed seated properly - if the bearing isn't all the way in, the snap ring won't go in properly.

 

But then I hit a wall again. The seals I picked up from CarQuest were incorrect. Well, actually the outer seal was okay. But the inner did not have the extended lip - instead it just looked exactly like the outer seal. I had to stop for the night since the shops were closed.

Edited June 6, 2012 by JPX

[JPX]

This morning I picked up Subaru's OEM seals. And sure enough the inner seal had the correct longer lip for going over the CV.

 

When I got home in the evening, I stacked up the Harbor Freight kit on the vise to conduct three operations:

1. Evenly and easily press the inner seal into the knuckle.

2. Evenly and easily press the outer seal into the knuckle.

3. Press the hub into the bearing and knuckle assembly.

 

1. and 2. when smoothly. I had to swap out press plates to make sure I was pressing the seals evenly. The old outer race came in handy for the inner seal.

 

3. needed a very small press plate for this operation. This is important to make sure the inner bearing is supported when pressing in the hub.

 

Almost forgot the brake dust shield. This is virtually impossible to install once the hub is mounted. Glad I caught this before I really started to crank on the hub.

 

Again this was an easy process once the press kit was set up. No power tools - only the big hand wrench was necessary. You have to make sure the press plate is oriented correctly so the hub can be pressed fully. If the plate is facing the wrong way, then the hub end will bottom out and feel like it is done - but you will still see the exposed sealing surface on the hub for the outer seal.

 

 

After all of this, reassembly of the front end was easy.....well except for the inner tie rod end I just spotted. I've already had to do the tier rod on other side. So that goes on the "eventually-to-do list". I eyeballed the strut mount bolt setting (basically "0" on the top eccentric bolt).

 

 

Took the car for a drive. And wow is it so much quieter inside now. That rumbling by my left foot is gone. What is funny about making a LOUD noise go away is now you can hear other sounds more clearly (tire noise, wind noise - oh wait, do I hear a wheel bearing somewhere in the back now???)

 

Alignment seemed to be okay - the car wasn't pulling either way. I'll hold off the trip to the alignment shop until I can see the tire wear pattern with this setting.

 

Mission accomplished:headbang: - even though not exactly the way I thought it would be accomplished.

[CNY_Dave]

So when torquing the axle nut were there a bunch of fairly difficult turns, followed by a very sudden increase in turning torque and then hitting the torque setpoint almost immediately?

 

On mine it took a bunch of turns to fully draw the 2 inner races together, was wondering what the heck was going on.

 

Once they met it hit max torque in less than a 1/4 turn.

[JPX]

So when torquing the axle nut were there a bunch of fairly difficult turns, followed by a very sudden increase in turning torque and then hitting the torque setpoint almost immediately?

 

On mine it took a bunch of turns to fully draw the 2 inner races together, was wondering what the heck was going on.

 

Once they met it hit max torque in less than a 1/4 turn.

 

I encountered the same thing on the axle nut, there was almost no turn between "hard to turn" to full torque.

 

But I didn't have that many turns with a wrench to draw the races together, mostly turned the nut by hand.....but I think that was because I had just pressed in the hub and the races were pretty much dead on to each other.

[Fairtax4me]

Whenever I've changed axles there are usually one or two turns that are just a bit more than what can be done by hand, but easily doable with even a small ratchet. Once the axle nut is snug there is only about 1/8 to 1/4 turn to reach full torque.

If the inner race preload hasn't been set (races pressed together) there could be several turns before the slack between them is taken out. This is why it's important to torque the axle nut with the wheel OFF the ground. If not done this way the bearing is pulled together while loaded and damage to the races or bearings may occur.

[gavinl]

Thanks to this thread and the recommendation of the harbor freight tool kit I got the front wheel bearing of my 98 Legacy GT replaced

 

Here are part nos. of the seals and snap ring (Genuine Subaru):

Inner Seal: 28015AA080

Outer Seal: 28015AA070

Snap Ring: 28035AA010

[michaelbteam]

So--If my local Subie shop charged almost $400 for one wheel bearing--sounds like a decent price to avoid all that aggravation??

[unibrook]

So--If my local Subie shop charged almost $400 for one wheel bearing--sounds like a decent price to avoid all that aggravation??

 

 

That all depends on you. If you have more $ than time, then yes it is worth it. I am a cheapskate, and I don't trust others to do as careful a job on my car as I will, so I do it myself. But I would not do the job for someone else for less than $300 if I were to charge for it. It is a pain, but doable in your driveway. Up on a lift it would be much easier on your back.

[Gloyale]

That all depends on you. If you have more $ than time, then yes it is worth it. I am a cheapskate, and I don't trust others to do as careful a job on my car as I will, so I do it myself. But I would not do the job for someone else for less than $300 if I were to charge for it. It is a pain, but doable in your driveway. Up on a lift it would be much easier on your back.

 

I charge $100 labor plus parts.*

*impossibly stuck bearings/damaged hubs add $50.

 

 

They get eaiser once you've done dozens:cool:

[JPX]

After replacing this driver side front wheel bearing and knuckle assembly, the passenger side decided to let go.

 

The fun continues here on this thread.