front wheel bearing service

rusnak · 05-12-2006, 05:49 PM

I've always been sort of nervous about the front wheel bearings (spinning on the spindle and causing wear) and so I repack them every year. Last year I noticed rust in the bearings and replaced them with new ones, then switched from Swepco grease to Mobil 1 synthetic grease. BTW I put a lot of miles on my 3.2 liter, like over 20k miles per year.

I use SKF bearings and races. I think these races were changed about 4 years ago and I don't mix races and bearing brands. This year I used Valvoline synthetic grease, and repacked them with the cone shaped grease gun repacker. I have noticed that after repacking, the bearings need to be readjusted after about 50 miles or so. I have begun to use more tension on the clamp thing against the thrust washer to make sure that the bearing isn't slopping around and machining down the spindle. I also started to shoot more grease onto the spindle, around the gap between the spindle and the hub, and onto the outer bearing before putting the thrust washer over the outer bearing. I also put grease in the dust cap.

Can anyone give some service and inspection pointers? I'd like to collect as much information on this topic as possible to learn (1) what is the proper amount of tension/ clunk in the rotors
(2) best way to repack em
(3) what to look for when you take em apart and inspect em.
(4) do you change the races each time you replace the bearings, or do you alternate the races (change them every other time you change the bearings). If I need to change the races, I might as well buy a hydraulic press, right?

bbh03 · 05-12-2006, 07:08 PM

Good topic. I use Redline CV2 grease. High quality stuff. I pack them by hand. Do you feel the packer works better?

afterburn 549 · 05-12-2006, 08:12 PM

what i think I know...are you spinning the wheel as you snorq the bearing into place..(preload) then back off till desired slop.(I go for no slop as it is a light car and a lil preload will never hurt them)

bbh03 · 05-12-2006, 08:14 PM

Use a snorq wrench.

Sorry, couldn't resist.

afterburn 549 · 05-12-2006, 08:20 PM

Snorq = well a tested calabrated arm.

LakeCleElum · 05-13-2006, 04:20 AM

I tighten the nut down fairly well to get everything seated. Then back it off till you get some play. As a final move, just finger tight and make sure the rotor turns freely, yet now play back and forth.

A far a applying grease, they make a tool that squeezes grease in between the bearing and races. This is the best way to go. As far as replacement goes, with normal use, every 100,000 miles is plenty. I worked in a auto service department in high school and college. Serviced dozens of wheel bearings, but never saw a failure......

rusnak · 05-13-2006, 11:36 PM

This is one adjustment that escapes me even after I think I have it figured out.

I used Redline grease in the past, but felt that it pounded out of the bearings. I really like LiquiMolly LM 1 or something like that. It's this German grease that I feel it is the best stuff out there, but it doesn't come in a grease cartridge, so I use Valvoline Super Syn now.

Yes, I personally feel that the grease packing cone shaped thing is the best way to get grease into the bearings because you can use far more pressure than you get packing them by hand.

I never saw a tool that can get grease between the race and the bearing though. That must thread onto the spindle before installing the thrust washer?

The standard for tightness in the Clymer, Bentley, and Porsche manuals state that the correct procedure is to tighten the clamp nut while spinning the rotor, back off, then re-tighten until you can barely move the thrust washer with a screwdriver without using a prying motion.

I find that this usually results in too lose bearings that clunk or cause the rotor to rub against the brake pads. And my worry is that the bearings will start to spin and wear down my expensive Bilstein RSR struts.

One more question: what do you look for when inspecting your struts? I haven't found a wear tolerance chart for RSR struts, but I assume they use the same bearings as the regular 911 struts.

BReyes · BReyes's Garage

You really want me to get my hands dirty today, don't you. Thanks. Good thread.

And you should not be nervous about this though, handle it, and work on your A list.

Regards,

afterburn 549 · 05-14-2006, 07:15 AM

enough ? ! wheel bngs are wheel bngs already evven ( lol ) but the cone tool works for all other stuff (cars) and mine........are you driving into deep water ??

rusnak · 05-15-2006, 10:57 AM

Deep water, not normally but this year.....yeah especially in norther California.