Front wheel bearings, too much play

EdHut · 03-24-2004, 02:12 PM

The bearings of my right front wheel have too much play, even when tightened to the fullest.

According to my mechanic it is not possible to tighten them any further because the parts have worn down too much over the years. The solutions he offered is to replace the entire strut assemply, or machine the existing one so that proper adjustment is possible again, or find a good (enough) used one.

Are these indeed the only solutions, or are there other ones?

Easiest route would of course be to get a new strut assembly, but these are no longer available for a 1966 911.

Rot 911 · 03-24-2004, 02:13 PM

Are these new bearings? What he is saying makes no sense. The bearings ride on their own races, not the strut. Unless he is saying the race is spinning on the strut, but I doubt it.

EdHut · 03-25-2004, 12:52 PM

I don't have the facilities to do work on my car myself. I don't have documentation (e.g. factory manual) that is detailed enough.

What you say makes sense though, and I'm very interested to learn how the front wheel bearings are fitted on the early (per-68?) 911's. If what my meachinic says is true, then the bearings are in some wearing down the front wheel strut, and 'just' replacing the bearings is not an option.

Maybe somebody can post detailed picture / schematic of the front wheel assembly so I can study it and learn how it all fits together.

Jim Sims · 03-25-2004, 05:15 PM

Just looked at a cross-section figure of this front hub and I agree with Kurt that the diagnosis only makes sense if the races have been turning on the spindle or within the hub instead of the rolling elements rolling on the races or if the bearings are very, very worn. Here in the US a new set of these bearings (enough for both front wheels) costs the equivalent of 40-50 Euros; they are basically a commodity as they are the same bearings as those installed on 25 million VW's. I would inquire further of the mechanic; has he taken apart the hub and checked the spindle and bore of the hub? All you may need is a new set of bearings and grease seals; do both sides if you do one side. Cheers, Jim

EdHut · 03-25-2004, 08:23 PM

Quote:

Originally posted by Jim Sims
Just looked at a cross-section figure of this front hub and I agree with Kurt ...

What's the source if the figure you looked at. Is there any chance that you post it here or email it?

Rot 911 · 03-26-2004, 05:14 AM

Quote:

Originally posted by EdHut
What's the source if the figure you looked at. Is there any chance that you post it here or email it?

If you go to the main Pelican Porsche page and look down the listings on the left side column, you will see a link for "parts diagrams". Here is a diagram for the front shock, strut and spindle:

Superman · 03-26-2004, 05:29 AM

Yes indeed, spindles get worn, particularly under the outboard bearing inner race. The inner race winds up 'spinning' on the spindle. Actually, the bearing still does the spinning. It's not as though the inner race"spins," but it can fail to make a tight fit against the spindle.

This is the case with my car. You can make a positive determination by removing the dust cap, putting your thunb against the hub and spindle at the same time, and rocking the hub back and forth. If the hub moves relative to the spindle, then this is what you've got too. Since my budget is limited (I'm saving for a 917), they'll just have to stay that way for a bit. It's not something to get real anxious about, IMHO.

EdHut · 03-26-2004, 10:20 AM

Thanks for the diagram. I totally forgot that Pelican has many of them online (way to go Wayne!)

I also found another good one in a Haynes manual, so I now have the full picture about how the bearings are fitted.

I think I'll take a closer look at the bearings tomorrow to find out if I got the same situation that Superman has.

Regarding Superman's remark about letting it stay how it is, I know for a fact that my car is not street legal according to Dutch law. I also feel the wheel wobble a bit when driving (not all the time).

Thanks for the help so far guys!

EdHut · 03-27-2004, 08:39 AM

Quote:

Originally posted by EdHut
I think I'll take a closer look at the bearings tomorrow to find out if I got the same situation that Superman has.

Checked them and I got the same thing. The other front wheel is fine though.

Which brings me back to my original question: how to fix the play that it currently has?

Eric Coffey · 11:08 AM

Quote:

Originally posted by EdHut
Which brings me back to my original question: how to fix the play that it currently has?

I'd try to find a new (used) strut.

rusnak · 07:49 PM

A couple of questions, hopefully answered here:

(1) I don't think I have #23 and #24 in the above diagram. I just have the bearings and dust seal (#29) that go on the hub, then I put the whole assembly on the spindle. Does anyone have a picture of #23 and #24?

(2) The amount of bearing play, otherwise known as "clunk" that is appropriate has always mystified me. When you can still move the washer back and forth with a screwdriver, there is way too much "clunk" and I suspect that the bearings are spinning on the spindle. To keep the bearings from spinning, I have to tighten the clamp #30 a little farther. I also have to tighten the clamp bolt down quite a bit to keep the clamp from coming loose. Does this mean the spindle is worn out, because the spindle itself does not look worn at all. Is this a tolerance in the .000 inch range? Am I squeezing out the grease if I tighten the clamp too far? Does anyone fill the outer dust cap with grease? How much grease do you put in the bearings/ spindle/ dust seal/ dust cap?

I should add that I have a hydraulic press now for my own bearing race replacement. This strange problem comes back about every 10-20k miles. Is this just the max lifespan of hard working front bearings?

Jeff Alton · 04-05-2007, 07:51 PM

You could use the "pull it back and forth" method mentioned above to decide if you need a new strut. But, I am sure you can source the specs for the diameter of the spindle and then mic yours to see if it is indeed worn out......

Cheers

rusnak · 04-05-2007, 07:56 PM

The "clunk" I refer to is with the car sitting on it's wheels. If the rotor were clunking around with the car up in the air, I'd pretty much know that the rotor or spindle is toast.

I never thought to mic the spindle, since it looks and feels like there is no detectible wear. I'll do the mic test. Can I use calipers?

Jeff Alton · 04-05-2007, 08:02 PM

Calipers would probably give you a fair reference. Then again, fitting a new bearing on the spindle with out the hub would give you and *idea* too as to whether or not there was some play. It should be a snug fit.

This would at least give you an idea as to whether or not you need to start shopping for a strut or two. But the bearing could be buggered to from wear or a bad install.

Cheers

rusnak · 04-05-2007, 08:05 PM

Thanks Jeff, I guess you sort of nailed it there.

I'm trying to determine if it's the bearing's fault or mine (bad install). If it's the latter, then I'm trying to mend my ways here.

Jeff Alton · 04-05-2007, 08:19 PM

Didn't mean to suggest your install was at fault! If the spindle is worn it could have happened at any time during the life of your car.

I just checked my digital caliper vs my Mic calibration block. It was within .02mm and repatable. So, you should be okay to use a caliper.

The bearing could be the problem too. Couple a little "manufacturing tolerance" with a wee bit of wear on the spindle, and it looks like the spindle is shot. That is why I prefer to measure.

Cheers

sjf911 · sjf911's Garage

Quote:

(1) I don't think I have #23 and #24 in the above diagram. I just have the bearings and dust seal (#29) that go on the hub, then I put the whole assembly on the spindle. Does anyone have a picture of #23 and #24?

#24 is the "race" that the dust seal interacts with to seal the hub on the back side. #23 is the O-ring behind it. These are both pressed on the spindle and do not come off when you redo your bearings. If they are missing (ie if you changed your struts and did not transfer these over) you may be wearing out your wheel bearings prematurely because of dirt contamination.

rusnak · 04-06-2007, 09:29 AM

Steve, I think that you may have identified the problem.

}{arlequin · }{arlequin's Garage

take measurements of your spindle diameters in several places and compare them against the factory specs. it's the only way to know for sure what is worn and what is going on.

too much wobble in the wrong place, tighten too much to try to 'fix' it, next thing you know you'll have so much heat build up that the spindle will fail.

how do you like your front wheels falling off when you're driving?

on a car this old, if i had to bet, early failure due to dirt etc, would be the last of my worries. 1966 spindles?? i'm pretty sure they're worn out.

measure to be certain though.

rusnak · 04-09-2007, 04:00 PM

I thought I'd follow up with some pictures.

I went through my collection of old parts that I store in a corner of the garage, and found some 911 Carrera struts in good condition. I drove the "spacer" off of the struts with a steel punch, and then installed them on the new struts with the o-ring properly seated.

Without the spacer the wheel seal can't seal out water and dust, so the bearing fails after about 10-20k miles. Also, the spacer provides a seat for the inner wheel bearing's inner bearing race.

I found that my struts were still in very good condition, and the new SKF bearings had to be pressed onto the spindles, since there is still a lot of meat on them. I pressed the inner bearings on by holding the hub with bearings in place with the thrust washer, then slowly threading the clamp nut on with a big screw driver. The inner bearing is pressed onto the spindle, then I back off the clamp and adjust the bearing according to instructions.

before:

after: