Front Bearings - Adjust, Repack, do nothing?

[Don Plumley]

Another post-autox question:

At tech, they said my front bearings were a little loose. You know, grab the wheel and shake.

So while the car is up on the stands, I took off the dust caps (thanks again to the info on the bbs on how to do that!). In the Bentley manual, it says the thrust washer should move slightly back and forth. In my car, I can't move the thrust washer with the "tip of a screwdriver" at all. Assuming I'm wiggling the right part.

So to me, it seems the bearing is adjusted properly. I hate to touch something that seems to be in good working order because my FU/Fix ratio is usually > 1.0.

On top of this, in the PO records it indicates the left front bearings were replaced. Lots of grease in the bearings and in the dust cap. But the right front cap is dry (no evidence it had any grease), and I can see the sides of the roller bearings. Here's a pic:



1) Help me better understand "Your bearings need ajustment" and what I'm seeing in the wheel?
2) Based on the pic, can you tell me if I should repack my right front bearings? (which will engender another thread...)

Thanks guys,

Don

[Early_S_Man]

Don,

I don't see a thrust washer in that pic! Why don't you shoot a pic of the other side and post it?

And, you might as well take the right wheel off and get ready to remove and clean the bearing.

[Don Plumley]

Hi Warren,

I reposted the image (refresh the thread) and there is an arrow to what I presume is the thrust washer. Maybe the angle of the photo throws this off.

Not that this matters, this is the "right" side. The left was full of grease, and previously had the bearings replaced (about 10K ago).

Think it should be repacked?

Thanks,

Don

[dickster]

if the bearings are correctly adjusted but still give too much movement - the bearings are worn and need replacing

[john70t]

If your going to repack it , you'll want to double check that the races are completely bottomed out(i.e. parrallel) in the hub and clean any residue of any grease remaining and that the grease squeezes out between the rollers. You probably don't want to pack more than a third full because it retains heat as well.
I put new bearings/races in some time ago and the bearings got loose after a bit of driving. There were a lot of other issues to be repaired-new rotors, steel lines, new strut etc-that I should have replaced all at once and done a complete job. When ya do half-ashed work ya do it twice
Someone told me to use locktight on the adjusting nut but I don't know about that one. FYI the washer does seem hard to turn even if the bearings haven't snugged. Try to push on the side.

[Don Plumley]

Since I didn't want to disconnect the caliper, I just pulled out the outside bearing and checked it over. All seemed fine. I repacked with grease and adjusted. Can barely move the thrust washer.

Ran around for a few miles. When I "grab the wheel and shake", there is a definte klunk. Huh??

Could this be the rotor hitting the brake shoes and not an out of adjustment bearing?

Any advice appreciated.

Thanks,

Don

[Tinker]

Don,

If you are racing the car, you want them on the loose side. Those bearings will grow when the get hot under hard braking. I see the thrust washer in your photo. When you pulled out the outer bearing, what did it look like? Any discoloring? I have never had a bearing go bad. There needs to be some play. Make sure you are spinning the hub as you are adjusting so you can feels the drag. Drive it a bit and readjust.

Tinker

[Superman]

Raise the wheel. Grab the tire and 12:00 and 6:00 and try to rockit back and forth. If you sense any play, it is probably too loose. These bearings are suppposed to be adjusted so that there is no play, but it is really a bit safer to have just a tiny bit of play. If your are this way, then your clunk is not a wheel bearing. You can take the outer bearing out pretty easy if you want and pack some fresh grease in there. The grease in the picture doesn't look too bad.

Next, I'd check sway bar mounts if I were looking for clunks.

[Don Plumley]

Tinker/Super:

Thanks - I did pull both outer bearings - no discernable wear. PO records indicate the Left front (right pictured) was replaced 14K mi/4 years ago. Interestingly, the replaced bearing was an SKF, while the "original" right bearing was made in Japan. Hmm...

My friend the wrench also said that a bit loose was better than too tight as you don't want to pre-load the bearing - contributes to early failure. So three votes for a bit loose.

Super - I did the rock test while the car was on the ground, and I was yanking with all my weight (because that was the way they did it at the Autox tech). I'll try your technique and see how it goes.

Thanks!

Don

[daburg]

I too have a klunk in the front left of my 78SC. I thought it was a loose bearing and I adjusted it but to no avail. I then replaced the bearing and still have a klunk. After much rocking and head scratching I discovered the klunk appears to be in the strut. I'm not sure what could be wrong with it (other than it is probable the original) I want to look at the strut but I am having a hard time getting the top nut off. Maybe you have the same problem.

daburg

[Dial91177s]

Looks as if you might have some old grease packed in based on the pic......I've just completed a repack of my front wheel bearings ('77 911S) today in prep for a PCA Driver's Ed. I too has a little "play" in the wheels ~ 1/8" wobble or so that was caused by two factors......washer too loose & not enough greased packed in the bearing & housing.

Here's the solution as I've just completed.... 2hr total job....and really quite easy !! It's actually too tight if you can move the washer around, and therefore since you'll have the large odd shaped wb nut off....it's a great time to clean out the old grease and/or water that may have accumulated and repack the bearings. I opted to replace the bearings with new, however this is not necessary if yours are seemingly in decent shape.

Clean all parts of old grease....using high-temp wb grease 400F or higher...this should be either black or dark green (Schweptco brand is the best)....force the green up thru the wide side of the bearing until you see it come out the top...this is done by pressing bearing into grease in your plam.....don't forget the latex gloves this stuff if a mess !! Once complete, reassemble and tighten nut down so there is medium play in the washer...it should take a bit to move, however not brute force....just less than snug would be ideal.

Make sure to clean/pack the wb cap before replacing....my left side was nearly empty of grease...no wonder I was having cornering issues with the car. I've road tested today and have seen dramatic improvement over this relatively quick & inexpensive repair.

New WB's - $7.50 each at NAPA
WB Grease - $6-9 per tub

Hope this helps !!

Brian

[Superman]

If you did the autocross wheel bearing inspection and it did not clunk, then your clunk is elsewhere. First choice goes to stuff like sway bars and struts.