Wheel Bearing, maintenance adventure on the Subaru Impreza.

When that pile of rust you drive doubles in value from filling it with gas, it doesn't make a lot of financial sense to spend $500-600 to pay someone to replace a noisy wheel bearing. It makes even less sense when this is the 4th time the same wheel bearing has needed replacing in roughly 6 years of ownership.

After the car left my daughter stranded last year, I paid a shop $1,200 for a tune up to get it running again only to have them tell me it needed another $1k in various other repairs such as a wheel bearing and valve cover gaskets. I was hoping to replace the car with something newer, but the COVID related chip shortages pretty much destroyed the used car market in 2021 making people sell junk for twice their worth.

My own goal of retiring in 2022 made spending another $8-10k on a car for my kid a hard pill to swallow so I let my son drive it until it couldn't be driven anymore. The car was marking it's territory wherever it parked, eventually needing a quart of oil every 2 weeks from the leaky valve covers.  Then it started throwing a check engine light probably needing a new cat O2 sensor. I figured I would just donate the car but a late night revelation came to me.

I could try to replace that wheel bearing myself and keep the car on the road for a bit longer. if I can't get the bearing out I could donate but if I managed to replace the bearing I could continue replacing the valve cover gaskets and whatever other maintenance items that need to be addressed.

I looked at the various tools I thought I would need and was expecting to spend around $200 on tools that I might not need again for a long time and then saw/read that Autozone and O'Reillys have free tools to loan for exactly this kind of project.

So with a plan of action, I ordered a wheel bearing/hub kit which includes a bearing, the hub, 3 seals, a snap ring and a new axle nut and since I was ordering I got a valve cover gasket kit also. This includes the gasket, the spark plug rings and the grommets for the fasteners. Subaru Wheel bearings are supposed to be the best quality and I can confirm that the Subaru Wheel Bearing was much heftier than the no-name brand (WJB ?) I was installing. (Subaru wheel bearing has a machined out center section that I imagine is to help with installing and removing)

Rust never sleeps, but I will paint over it to try and slow it down.

In a few more years, there won't be enough metal to jack up the car. Hopefully we will be in a situation to donate the car for parts or give it to a needy friend if it's still safe to drive.

With the wheel in the air, I verified that the wheel does not spin smoothly, a reasonably good sign of a bad wheel bearing. 

The first hub puller I borrowed was flatter but didn't fit over my hub because it was intended to be used with a larger hub, so I went back and got a different puller. The puller and the slide hammer are separate loaner tools so each one has a credit card deposit in order to be able to take it home.  Deposit was $119 for both items.

As soon as I removed the drum, I noticed that the last time I worked on the brake shoes on this car probably 4 years ago, I didn't install it correctly and then I remembered the time a firestone tech told me something was installed backwards in the drum brake.  OK, made a mental note to fix it before I put the wheel back on. I distinctly remember not wanting to worry about it 4 years ago because the car would be traded really soon when my oldest decided to eventually buy a car for herself. Here we are 2 drivers later.

The slide hammer worked wonderfully, but required me to bang on the thing for 2 or 3 hours before I finally got it off. That activity aggravated an old thumb injury as well as made my wrist hurt. I had some concern about being able to get a bolt off that seems to be frozen on every Subaru from this era but it came right off with my big impact gun. Probably since the bearing was just done 2 years ago.

It took a while for the Autozone folks to locate the bearing puller I needed, but the tool was brand new and the deposit was $175. I've seen smaller kits as low as $60 on the Internet. A savings is a savings and I'm looking at almost $300 saved as well as all the space an unused tool would be taking up in my garage. I did have to buy a $5 32mm socket to get the axle nut off. Luckily, the bearing puller needs a 32mm socket as well so I already got more than 1 use out of it.

After struggling for a while, I finally got the wheel bearing out.  In the end, my impact gun didn't have enough torque to tighten it down (never figured out how to go forward on my big impact for some reason) but I thought it was because the smallest drift on the bearing puller was too big and hitting the bearing stop on the back of the drum assembly, but I tried a ratchet with an breaker bar extension (I'm using my Hydraulic Jack Handle for this) I got it to move but needed another 20 minutes of tightening before the bearing came free.  Since I was looking at some successes, I had my son start working on pulling the valve cover off since my bad back doesn't want me to bend over the car to do it.  It's his first time wrenching so I wanted to make sure I'm watching him and providing guidance. Something my dad never had time to do with me.

The inner race of the bearing was rusty and gritty but the outer race was still nice and smooth. Obviously water intrusion from the axle side. Not sure if it's poor design or if something just isn't to factory spec since the first accident that my father-in-law had in this car when it was less than 1 year old.  I suspect next time it goes bad, we could just keep driving until the inner race wears out and then the outer race will just be nice and quiet.  Likely not a realistic condition but it could probably be done in a pinch. Damn the noise, continue driving!

Not having any experience with this type of project, I relied heavily on various youtube videos. Unfortuntely they never cover all the potential pitfalls nor do they explain areas where a novice like me could really use some extra guidance when faced with an issue.

• Pull the hub before removing anything else. You need some resistance to the slide hammer for it to work optimally. I made the mistake of pulling everything apart before using the slide and there was too much movement to pull the hub effectively. I had to re-fasten the suspension arms.
• use a bearing puller cup that matches the mounting surface and not fitting partially over the mounting surface because the tightening action could make that cup nearly impossible to remove when it slides down. This cup was slightly too large and nearly impossible to remove once it settled too far down the bearing mount. I managed to remove it by tugging it while gently tapping it from every side to coax it to come loose. Luckily, the hub mount is straight and not flared. Using a big hammer and more force didn't move it at all.
• a lot of force is required to pull the hub and the bearing, try a hand tool with a breaker bar if the impact gun is not budging the wheel bearing. For removing the hub, the only tool is the slide hammer (bigger than 5lbs is always better).
• Don't use the old bearing to drive the new bearing because it will get stuck
• The bearing comes apart very easily to add additional grease, make sure to keep everything clean
• Banging on stuff makes sandy grit fall out of the crevices which can get into the bearing surfaces after they are installed but before the axle is back in place. 
• clean the axle mating surface that will touch the seal and also pack some extra grease behind the seals to delay water entry.
• I borrowed from Autozone and think it might be helpful to reserve the tools online to ensure that the local store has it. I tried borrowing from a store close to work, but they had none of the tools to borrow. I ended up going back to the first place that had everything. I learned not every store has every tool.
• When installing the bearing brace against the bearing housing when tightening the bearing puller
• When installing the hub, brace against the bearing and not the housing.
• This video covered the most detail for me: https://www.youtube.com/watch?v=CInFJDz11II&list=LL&index=3

I may have introduced a little grit from not keeping things clean because the hub rotation is not 100% smooth after installation of the hub. I could turn it 3 or 4 revolutions and feel a slight hitch but as I continue turning, it goes away and I won't notice it again for a few more turns.  It's probably going to be an issue, but I don't want to pull everything off and redo everything. I'm hoping the bearing and grease just needs a chance to break in but not having high hopes at this point. It might be good enough to drive for now. **Update: It wasn't .. see post mortem below**

I over-torqued the axle shaft nut. I was trying to hit 140ft-lbs (the video didn't mention measurement, only the number) but looking it up, it appears to be 108 ft-lbs or 140 NM.  That would explain why the wheel won't turn now and when I move the car there's a terrible metallic squeal. After retorqueing the axle bolt, it looks like the damage was done and I will need to go back to square one and redo everything. Bummer. $55 out the window for that bearing kit.

I had to locate a picture of the drum brake assembly and got it back together. I know I winged it last time and I'm glad it's finally fixed.

Valve cover gasket replacement was fairly straight forward. My son's first wrenching experience was a success. He only needed to loosen and relocate the airbox on the passenger side and the windshield washer bottle on the driver side to get access. He did experience lots of hand cramping due to never needing to have grip strength to hold anything besides his phone. I stayed close to offer advise and assistance and he's already looking forward to his next wrenching adventure.

The original gasket was hard and cracked in a few spots and probably where the leaks were coming from. 

Trying to access the driver side bolts

Passenger side engine bay

Cleaning the valve cover

Post Mortem:

On the 2nd go-around, everything came out pretty easily since I was working from experience and also got my son to wack on the slide hammer for an hour instead of me. The inner bearings broke apart as they came out with a few of the bearings dented or chipped from over-torqueing the axle nut.  

It looks like I made 2 errors in the first install.  I installed the hub with a larger disc against the housing instead of using the smaller disc against the inner bearing race. I over torqued the axle nut. Either mistake would have caused issues as evidenced by the non smooth turning of the hub upon first install.

In a perfect world a rear bearing replacement would be just a 2 hour job if you take your time. Damn the rust and grit of the real world.