Questions on front bearings

[jlynch1960]

I was working on the brakes awhile back and got hung up with a frozen caliper piston. While I had the fronts apart, a few issues came up. 84 Carrera.

What is the correct level of "play" in the thrust washer inside the spindle nut? Instruction is to tighten the nut then back it off so that washer can be moved slightly "back and forth" with a light touch. How slight is slight and is this referring to lateral deflection or play in its plane of rotation? As the washer is notched - not a lot of room for play to begin with. Is this to allow for heat expansion?

Also, how much grease should there be in the spindle/bearings. Mine looked pretty well coated as this had been done by a shop a few years back, but I was wondering if I should pack some more in. Recommendations on brand?

Any thoughts appreciated. Thanks.

[NYNick]

Well, I'm no expert but have done this to 3 cars in the last 2 years. Personally I think people over grease these things or maybe over time, no one bothers to takes them apart, cleans the spindles, the hubs and the bearings and then re-assemble the whole shooting match. I prefer this method so I know what I've got. Your mileage may vary.

The car I did last month was absolutely over-slabbered with grease. Not necessary. Sure you have to 'pack' the bearings, but enough is enough and too much is too much. Hell, there was an inch of grease just in the grease cap!

Once you tighten down the nut, you back off a tad. Spin the wheel and if it spins freely, good job. Now rock the hub or rotor back and forth...if it moves at all the nut is too loose....or your bearings are shot. Tighten the nut until you get a free spinning wheel and no rocking back and forth. If you can't achieve this equilibrium, your bearings need replacing.

Retighten after 100 miles.

[cabmandone]

I just repacked my inner and outer bearings. I just tightened the nut and then backed it off until I could take a flat blade screwdriver and made sure it took a bit of effort to get the washer to move. I then mounted the tire to make sure there was no play in the bearings by doing a normal bearing check with one hand on the top and bottom of the tire and then pushing and pulling on the tire to feel for play. Once I had no play I figured that was good enough. As NYNick suggested, I'm going to drive and then recheck for any play but don't think I'll have any. The reason I installed the tire is the first time I tried feeling with just the hub and felt on play. When I put the tire on I could feel play.

[Oneredspyder]

Hello, I just replaced the front wheel bearings on my 86 911 with 87,000 mi on it. When I put it away for the winter I knew something was wrong with the front end and jacked it up. The right front wheel had some looseness in it that I did not like. Upon further investigation realized that the bearing was loose or worn. I replaced both inner and outer bearings on both wheels. I looked at several good you tube videos, but some did not replace the races, a big mistake. In any case I noticed that I was not the first one to get into the bearings. In the process of tightening the outer pinch nut I could not tighten the nut tight enough to cause any drag on the wheel. Took the wheel off again and looked at the races, they were all seated down. In Spite of that I could not get the nut tight enough to drag the wheel. I added a big washer under the tabbed washer, tightened it down to start dragging the wheel and backed off 1/4 turn, spinning free. I marked where both pinch bolts are, and will check them in 100 miles.
Any thoughts?
86 Carrara
66 Healey 3000
74 Norton 850
2011 BMW 328i

[wrxnofx]

Originally Posted by Oneredspyder

Hello, I just replaced the front wheel bearings on my 86 911 with 87,000 mi on it. When I put it away for the winter I knew something was wrong with the front end and jacked it up. The right front wheel had some looseness in it that I did not like. Upon further investigation realized that the bearing was loose or worn. I replaced both inner and outer bearings on both wheels. I looked at several good you tube videos, but some did not replace the races, a big mistake. In any case I noticed that I was not the first one to get into the bearings. In the process of tightening the outer pinch nut I could not tighten the nut tight enough to cause any drag on the wheel. Took the wheel off again and looked at the races, they were all seated down. In Spite of that I could not get the nut tight enough to drag the wheel. I added a big washer under the tabbed washer, tightened it down to start dragging the wheel and backed off 1/4 turn, spinning free. I marked where both pinch bolts are, and will check them in 100 miles.
Any thoughts?
86 Carrara
66 Healey 3000
74 Norton 850
2011 BMW 328i

Almost sounds to me like you're missing the spacer ring in there. The inner bearing rides on this spacer ring. It should be #24 in this image:




You can also see it in this Pelican image (the red arrow is not pointing to it, FYI):

[Luccia at Pelican Parts]

SKF, FAG and Genuine are all great brands: 1984 Porsche 911 Carrera Coupe - Bearings. Careful, depending on where you purchase them from there has been issues with counterfeit SKF bearings, but we do sell the real ones. Thread on that over here: Rear wheel bearings - Timken, SKF, or Porsche?. Let me know if you have any questions.

[Oneredspyder]

Wow. I have a question about the spacer ring. The inner seal sits on the inner race of the spindle. Is the spacer ring placed on the spindle next in the assembly? And is the spacer ring loose on the spindle? Because I never saw it on either side. The wheel bearing was worked on before so who knows, maybe it is not there. Well, I certainly know how to take it apart!
Thanks

[Oneredspyder]

In the photo of the spindle above, is the spacer on the spindle?

[JRSIII]

Yes. Green arrow.

[wrxnofx]

Originally Posted by Oneredspyder

Wow. I have a question about the spacer ring. The inner seal sits on the inner race of the spindle. Is the spacer ring placed on the spindle next in the assembly? And is the spacer ring loose on the spindle? Because I never saw it on either side. The wheel bearing was worked on before so who knows, maybe it is not there. Well, I certainly know how to take it apart!
Thanks

The spacer ring sits on the spindle, and is on "tight" with an o-ring. I didn't remove mine when I replaced my bearings. Most people need a wheel puller of some sort to remove them.



When you slide the hub onto the spindle, the inner seal seals against that spacer, and the inner bearing rides on the spacer.

[ddubois]

On a related note, any idea why the roller cage would deform like this? The old bearings looked like this so I replaced the bearings and races with new, and the new bearings promptly did the same thing. There is no binding in the rollers and it doesn't effect the roller to race interfaces, it just looks bad. The bearings are properly greased and adjusted.

[pete3799]

Something is seriously wrong here.
Post a picture of both sides of your hub and the spindle.

[mepstein]

That cage is hitting something. That means something will probably break. Probably at the worse possible time. It needs to be fixed.

[manbridge 74]

Wow, take a pic from the side. Looks like incorrect size.

The reason for Porsche wanting the bearing a little on what feels like the loose side of normal is because the hub is aluminum and expands with heat, especially at the track. I have adjusted them slightly tighter but still with just a bit of play at 12 and 6 o'clock. The 911 is not a boat trailer!!

[chris_seven]

There are many different bearing kits on the market and the size of an individual bearing may vary slightly in terms of ID and width depending on the manufacturer.

As long as the track is the correct size and the race being used is correct for the track small differences really don't matter.

It is important that the track and the race are matching parts and both components always need to be replaced at the same time.

It is common practice that only the bearing is replaced when the track looks OK but this is not really a good practice and IMHO should be avoided.

Grease Packing bearings correctly is a useful skill and this Timken sheet explains how to do this and although it is mainly for truck bearings is still applicable.

http://www.timken.com/pdf/10824_CV14%20Packing%20A%20TRB%20With%20Grease.pdf

We tend to set bearings to the lower limit of between 0.001" and 0.002" axial clearance. The general rule is 0.001" to 0.005" but on a hard driven car I think the upper limit is too loose.

We use the old-fashioned method of tightening the hub nut to around 60 lbsft whilst rotating the hub and then backing the nut off by around a turn. We then re-torque to 10lbsft again whilst rotating the hub and then back off by about 1/4 turn.

If the axial clearance is correct we then lock the clamping device but if not we repeat the procedure.

Very hard driven track cars will wear out wheel bearing much more quickly then we imagine and on our Asphalt rally cars we used to change them 2-3 times a year.

Over the last few years have seen a fair number of 911 wheel bearings that look like the one's shown in the above photographs.

Our conclusion is that the car has previously been maintained by 'dummies'

[911Maverick]

I researched this quite a bit two years ago when I spun a bearing race at the track. Turns out I didn't sufficiently pack the bearing on my driver side so it was my fault. But in that research I found what I feel is the best "shade tree mechanic" way to check bearing fitment. I did the following and it seems to work well.

1. Pack bearings
2. Place hub/rotor onto spindle and apply keyed washer and nut and then tighten until the brake rotor starts to not spin freely.
3. Back off 1/16th of a turn (give or take).
4. Leave off dust cap
5. Remove center cap from wheel and place onto hub
6. Tighten with 2-3 lug nuts
7. Use wheel as leverage to check for play at 9/3 and 12/6 then spin.
8. You should feel an ever so slight amount of play in the wheel and it should spin freely
9. Take wheel off, apply dust cap, reattach wheel and torque lug nuts to spec
10. Go for a hearty drive, at least 30 minutes of spirited driving
11. Stop somewhere and check for play. If it is the same or less, good job!. If it is worse then either jack it up there and adjust or limp home and adjust.

[Oneredspyder]

Originally Posted by wrxnofx

The spacer ring sits on the spindle, and is on "tight" with an o-ring. I didn't remove mine when I replaced my bearings. Most people need a wheel puller of some sort to remove them.



When you slide the hub onto the spindle, the inner seal seals against that spacer, and the inner bearing rides on the spacer.

Ok, the inner spacer ring is on there. I am going to drive the car a short distance and recheck the play. Thank for you help.

[ddubois]

Originally Posted by ddubois

On a related note, any idea why the roller cage would deform like this? The old bearings looked like this so I replaced the bearings and races with new, and the new bearings promptly did the same thing. There is no binding in the rollers and it doesn't effect the roller to race interfaces, it just looks bad. The bearings are properly greased and adjusted.

I took everything apart and the cage is not hitting anything and the rollers roll freely. The hub spins freely with no noise, grinding or notching. I confirmed the outside race is fully pressed and seated in the hub. I checked that the cage outer plane is between the outer planes of the bearing races, i.e. the cage is not touching the outer race in the hub or the tab washer when everything is seated. When I adjust the bearings I follow the Porsche manual and adjust until I can 'just' move the tab washer. Before I took everything apart I confirmed I could still 'just' move the washer and confirmed there was no rocking with the wheel. Bottom line is the cage deforms but doesn't hit anything or effect the roller bearing operation. So I don't know, maybe my definition of 'just' is tighter than Porsche's definition and it's too tight causing the cage to deform? I'm tempted to install new bearings/races and adjust the bearings a little looser (the loose side of 'just'). SKF bearings on a 71T that only gets driven maybe 1k miles/year (less than 2k miles on these bearings).

[Claus Poulsen]

How far do you insert the screwdriver when you move the tab washer?
I deformed my old ones like that checking the movement. They are quite soft and easy to bend. Be careful only to move the washer.

[ddubois]

Originally Posted by Claus Poulsen

How far do you insert the screwdriver when you move the tab washer?
I deformed my old ones like that checking the movement. They are quite soft and easy to bend. Be careful only to move the washer.

Yeah, I was thinking about that while I was checking things. Definitely a possibility and the best explanation I have thus far. Add it to the list of 'easily done dumb things' like adding too much oil. I'm picking up new bearings today.