>Hi!
>The passenger side front wheel has some play in it on my '84 928S. I'm not
>sure if it's a wheel bearing or what... The car is sitting on the ground:
>if I grab the tire and shake back and forth (meaning I have my hands at 3
>o'clock and 9 o'clock) it doesn't have any noticeable play back and forth.
>When I rock it up and down (hands at 12:00 and 6:00, roughly), it gives a
>little bit back and forth.
>What's the problem?
>What does the fix entail?
>Need any more info?
>Thanks everyone!
>-Jon Franks
>PCA Chicago Region Member
>RennList Member
>'94 968
>'84 928S
>
From: C.S. Mo [news@pulselabs.com]
Sent: Monday, July 30, 2001 1:12 AM
To: 928
Subject: [928] Re: What's this problem? Wheel bearing? Ball joint? Tie
rod? What?!

Sounds like your wheel bearing. I believe left/right play would be the 
tie rod. I think Wally has a long post detailing how to tighten/check 
your wheel bearings. However, in short:

To tighten the bearing:

1) Loosen the lug nuts.
2) Jack up the car
3) Put a jackstand somewhere. :)
4) Take the wheel off.
5) Take the bearing cap off - it's the big gray thing in the middle of 
the hub. It is just a compression fit. I generally use a large 
screwdriver and a hammer to remove it but that leaves ugly marks all 
around it. I've heard of some people using large vice-grips and then 
wiggling it out but I've never tried doing so.
6) Once the bearing cap is off, there's a compression nut with an socket 
cap bolt in the side for locking it down. Loosen the socket cap bolt, 
which will enable you to turn the compression nut. There's a cutout in 
the hub to allow you to get an allen key into the socket cap bolt - you 
may have to rotate the hub to get to it. Don't take the socket cap bolt 
all the way out!
7) You want to tighten the compression nut down so that the washer behind 
it can be just barely moved with a screwdriver.
8) Put the wheel back on without putting the bearing cap on. You only 
need 3 lugnuts for this - check your play. If there is no play up/down in 
the wheel and you can barely move the washer with a screwdriver your 
wheel bearing is set just right. Take the wheel off, replace the bearing 
cover and reassemble. Otherwise loosen/tighten the compression nut.

If you're going to go to all this trouble, you might want to replace your 
wheel bearings. To replace your wheel bearings:

After step 6 above, loosen the socket cap bolt and take the compression 
nut off. You'll then be able to slide the hub off the spindle. (It may be 
easier to do all this if you take the rotor off but that may be asking 
for trouble, depending on the condition of your rotor's screws) You'll 
need to replace the inner and outer wheel bearings - getting the races 
out/in is kind of a pain if you don't have a bearing press..etc. If 
you're carefull you can do it with a cold chisel and a hammer.

Once you have the bearings and seals out, clean everything really well, 
put the new bearing races in, grease everything - I use Redline NLGI#2 
(?) grease, however there seems to be several schools on what grease to 
use.. Then put it all back together, adjust as in steps 7, 8 above.

I'd recommend Timken bearings - Autozone carries them for around $15-18 
per wheel. Pep Boys carries the seals for around $5-10.

The whole project can be done, for the first time, in an afternoon. The 
second time should take about an hour or two.

--C.S.




From: Wally Plumley [mailto:wplumley@bellsouth.net]
Sent: Monday, May 19, 2003 10:56 AM
To: 928
Subject: [928] Re: front wheel bearing


At 11:57 AM 5/16/2003, Martin Bishop wrote:
>I was doing my front wheel bearings last night and the inner bearing was
>strange.  It has been too long since I took them out so I completly forgot
>what they should have looked like.  The Races where not taken out when I
>removed the bearings, so I just dropped in new bearings.
>
>The thing was that the bearings do not seem to be held into place with
>anything when not mounted.  The repair manual says to put the cap thing
>flush mount with the top of the hub carrier.  If you do this it seems to
>allow the bearings to move out of the races.
>
>Is this correct?  I hope so.

When properly installed, the inner front wheel bearing will be kept from 
falling out of the hub by the grease seal. The outer diameters of the 
grease seal and the inner bearing race are the same, so the inner diameter 
of the seal opening must be smaller than the bearing. The seal should be a 
press fit into the hub.

The grease seal does NOT hold the bearing tightly in place, however. The 
bearing can move around freely. Both bearings are held in place and 
adjusted by the nut.

Adjustment of the nut is critical. Too loose or too tight will ruin the 
bearings, and this can lead to serious safety issues.

The goal in adjusting standard tapered roller bearings on the front hubs is 
to have zero preload and zero end play. The bearings will live with some 
end play, but this will introduce looseness into the steering. The bearings 
will usually fail if there is excessive preload.

The best procedure is that used in the auto assembly plants.
1) Jack the car. Remove the wheel.
2) Carefully pry the brake pads away from the brake disk just enough to 
allow free rotation of the disk. If you pry them too far, you may force 
brake fluid out of the master cylinder.
3) Remove the bearing dust cap. This cap is very tight on a 928. You can 
use a block of wood and repeatedly tap outward on the cap, turn and tap, 
turn and tap, ad nauseam. It will eventually come off. Very large 
Channel-Locks work also, but try to avoid scarring the cap. Or, of course, 
you can use VW Puller 9165 on VW Tool 771, as specified in the manual.
4) Visually inspect the bearing and grease. A properly lubricated and 
adjusted front wheel bearing should last forever. When I was active in SAE 
(Society of Automotive Engineers), I had a friend who was an application 
engineer with a large bearing company, and another who was an applications 
engineer with a large oil company. They agreed that you were more likely to 
hurt than help by periodically repacking your wheel bearings. They also 
both agreed that you should never use the old-fashioned stiff "wheel 
bearing grease" in a wheel bearing. The grease that they both recommended 
was soft, sticky, black moly grease. There are now special high-temp wheel 
bearing greases that should be fine, however.
5) Loosen the Allen bolt on the locking collar. While turning the hub 
(keeping your fingers out of the slots in the brake disk!), firmly tighten 
the locking collar. As tight as you can get it with a large pair of pliers 
should do. Stop turning the hub, and loosen the locking collar. Tighten it 
as tight as you can with your fingers alone - no tools! Tighten the Allen 
bolt to 11 lb/ft.
6) Check the hub for free rotation - it should rotate with no sign of 
bearing drag. Check the hub for end float (free play) - there should be no 
free play.
7) Re-install the dust cap.
8) Lightly lubricate the wheel studs with a non-graphite grease, and 
re-install the wheel. Torque the lug nuts to 96 lb/ft. Grab the wheel at 
top and bottom and try to shake it - there should be no perceptible looseness.
9) Firmly apply the foot brake to return the brake pads to the normal position.
10) Repeat on the other side (once only).

Wally Plumley
928 Specialists
www.928gt.com