Proper way to remove wheel bearings

fredmeister · fredmeister's Garage

I have removed the front hubs on my 911SC and need to replace the bearing races and install new races and bearings.
What is the proper procedure to remove the old races from the aluminum hubs and reinstall new races?
How often should bearings be replaced and how often do yuo guys repack them?
Owners manual says to repack them every 30k miles or possibly 15k miles (don't tremember exactly)......both seem excessive to me.
Called a few dealers and shops and prices ranged from $80 to $150 to do this for me......seems excessive too considering it is only removing and reinstalling races in hubs that are already out of the car and cleaned up.

Zeke · 01-12-2005, 07:38 PM

You can drive out the races with a drift, punch or pipe. Putting them in is different. You might want to freeze the races and heat the hub.

Emission · Emission's Garage

I removed them myself with a hammer and an aluminum rod (take your time). A shop pressed the new races in for $20 cash.

Willem Fick · 01-12-2005, 11:49 PM

According to Bentley, the hub should be heated before attempting the removal process - I think 160deg cent, but can't remember. The book describes in great detail how to do it, yet I felt more a ease having a good p-car wrench do the job!

Cheers!

Willem Fick

Par911 · 01-13-2005, 05:50 AM

Quote:

Originally posted by fredmeister
Called a few dealers and shops and prices ranged from $80 to $150 to do this for me......seems excessive too considering it is only removing and reinstalling races in hubs that are already out of the car and cleaned up.

Fredmeister, are there any ring and bearing/machine shops in your area? After replacing my front wheel bearings once, I chose this time around to take the the hubs to a shop. I took the them to a local ring and bearing shop, and they were able press the new wheel bearings in for $30.

Superman · 01-13-2005, 05:57 AM

A press is nice, and this is the conventional way, but I think Willem is correct. I believe the specified way is to heat the hub. That's what I'd do. If you heat the hub, the races should come out quite easily. Then, put the hub back into the oven and the new races in the freezer. Very possibly, the new (frozen) races will fall down onto their seats in the hot hub. Pretty slick.

na2ub · 01-13-2005, 05:58 AM

I heated mine in the BBQ prior to removal with a hammer / punch. Although it worked, I dinged up the steel in the area with the punch. Maybe that aluminum rod or a proper fitting pipe would have worked better. I dropped the new frozen races in and used the old race over them to bang on to seat them. That worked pretty well with little taps all the way around.

Doug

Rot 911 · 01-13-2005, 06:10 AM

Are you guys kidding? I've done a number of Porsche hubs myself. First remove the inside bearing, it is held in with the grease seal. Now clean the old grease out. Look inside the hub at where the race sits on the seating surface for the race. You will see two notches 180 degrees apart. These notches allow you to take a punch or drift and by hammering alternately on opposite sides of the race, drive the race out. No need to heat the hub up. Now do the same for the outer race. To install the races lay one on the hub opening. Place a block of wood on the race. Now lightly tap the race so it just starts to seat, maybe a 1/32 of an inch. Make sure it is seating the same depth all around. Now get a socket the same size as the race. Set the socket on top of the race. Place block of wood on the socket. Using hammer, drive race in. Makes sure it is going down evenly on all sides. Start to finish should take you all of about 10 minutes.

Emission · Emission's Garage

Oh, I heated mine in the kitchen oven... the smell of burning grease was interesting, to say the least. I thought my wife was going to kill me. Send your significant other out shopping whenever you cook Porsche parts...

Jim Sims · 01-13-2005, 06:57 AM

"two notches 180 degrees apart". Not all the 911 front hubs have this feature. In some, all there is to apply removal force to, is a small exposed edge of the back of the fixed race. Jim

cmcfaul · cmcfaul's Garage

Did mine in the BBQ. They literatly just drop in / fall out when you get the Hub hot enongh.

Chris
73 911 E

ChrisBennet · ChrisBennet's Garage

See what I posted in this thread: Front wheel bearing races for the reason you shouldn't just "whack them out".
The short version is that whacking them in/out without heat will destroy the press fit.
-Chris

Rot 911 · 01-13-2005, 07:31 AM

Ok, you guys may be winning me over. Let me ask this question. Can you use a torch instead of heating in the oven? Just take a torch and evenly heat around the hub where the race goes in?

Zeke · 01-13-2005, 07:36 AM

When you heat the hub to remove, both parts heat. Sure, the rate of expansion is different, but still, both parts get hot. Not a great advantage if your timing isn't ideal.

I really can't see how this works as well as the heat/cool process fro installing the new ones.

BTW, not everyone has a big enough socket for the big race and getting the socket on the edge is tricky.

Bottom line, if you are in doubt, take your hubs down to the machine shop preferably at the local FLAPS where they are used to doing this. A local brake shop would be good also. A specialist, not some place that does brakes like Pep Boys.

No intent on slamming Pep Boys, or anyone that has anything to do with Pep Boys, just an axample.

aj88cab · aj88cab's Garage

My steaks I like "medium-rare" but the hubs need to be "well-done". cmcfaul was right - heat the hubs good and hot and freeze the races and the old one will almost fall out and the new ones drop in without much pushing at all. The first hub I had to hit a few time with the "tool" I modified (see below). The second hub which stayed on the grill was hotter and the races fell out with a tap and the frozen race just dropped in (it actually fell out when I turned the hub over to install the other race). You will need a good pair of thick leather gloves to avoid 3rd degree burns.

Speaking of Pep Boys that is where I got this Seal & Bearing Driver kit. Took about an hour with the Dremel and disc sander to do the mods. My hubs had the "notches" that Jim Sims mentioned, so this may not work for all.

Good Luck
Andrew

Jim Sims · 01-13-2005, 07:58 AM

Hubs are aluminum and races are steel; thermal expansion rate of aluminum is roughly twice that of steel. Heating is significantly helpful; an oven or a hot air gun (one can buy the paint stripper type for $30 or less)i s much preferable to a torch. If you are inexperienced one can overheat items with a torch. Jim