Date: 25-Jun-1996 19:41:34
From:
Subject: Re: <E28> Front Wheel Bearing Replacement

Rebel A. Cole asks about E28 front wheel bearing replacement:

>...Anyway, I've read through the Bentley's manual, and this
>appears to be a far more complicated task than any I've
>attempted thus far (e.g., tie rods, control and thrust arms
>replaced), requiring a puller and (according to Bentley's)
>BMW special tool 31 2 110 to press the bearing onto the stub
>axle. Is there anyone out there who has tackled this job and
>who would be willing to share their experience with me before I
>commit to doing it myself?

Rebel,

It's not as hard as it sounds. I recently replaced my E28 M5 bearings (ABS E28 bearings are all the same) when I pulled the brake dust shields off for improved cooling. My car had 116,000 miles at the time, so it seemed like a good idea to replace the bearings (the bearings are included as part of the hub assembly -- that's why they are so expensive).

Special tools needed:

1. 46mm (or 1 13/16 inch) socket for the hub nut. The socket

   needs to be less than 64mm outside diameter to access the recessed nut inside the hub.

2. Six inch, three-leg puller to remove the hub assembly.
3. One foot long section of 1.5 inch pipe for pressing on the

   hub assembly (standard size galvanized pipe, which is the same diameter as the inner bearing race). A pipe coupling can be threaded on one end to press on the inner dust shield.

1. Jack car and remove wheel, five 17mm bolts.
2. Remove the hub dust cap.
3. Straighten crimped section of the hub nut and remove. Note

   that the Bentley Manual says to replace the wheel before removing the nut (so the car won't fall off the jack).

     My car did move around some when I first tried to remove
     the nut.  The 46mm socket (61mm OD) was too big to fit inside
     the 60mm hole in the wheel, so I just whacked the breaker bar
     with a 4-pound hammer.  This loosened the nut without disturbing
     the car on the jack.

4. The outer hub flange is the only location available for hooking

     the puller legs.  The inner race is a press fit on the stub axle
     while the outer race is a press fit in the hub.  So when you
     pull at the outer hub, the inner race usually stays on the axle 
     and the outer race stays with the hub (bearing comes apart).
     If the inner race stays on, just use the puller again to remove
     it from the stub axle.

5. There is no reason to remove the hub assembly's metal inner dust

     shield unless it's damaged, or you want to remove the brake dust
     shields as I did (the brake dust shields are held on with three
     10mm bolts).  
     
     If you do remove the hub dust shield, a 1.5 inch pipe coupling 
     (larger diameter than the pipe) can be threaded on the section
     of 1.5 inch pipe and used to press on the new shield.

6. Place new hub assembly (bearings are part of the assembly) on

     the stub axle.  Carefully press the hub assembly on evenly 
     (1.5 inch pipe which contacts the inner race is tapped with a 
     hammer). 

7. Install a new hub nut (214 ft-lb) and stake the edge so it

cannot loosen.

     Since I don't own a 3/4 inch torque wrench, I went with 
     Paul Hahn's tip of using a bathroom scale and the breaker bar
     torque arm measurement.  With the 1.5 foot breaker bar held 
     horizontal, I stood on a bathroom scale and tightened until the
     scale read 140 lb more than my weight.  
     1.5 feet X 140 lb = 210 ft-lb, so close enough.

8. Install a new hub dust cap and replace the wheel.

Parts List (purchased from Bekkers 800.624-5410)

Two of each part needed:
31211 128 336 Hub nut$ 4.69 each
31211 130 124 Hub dust cap $ 2.44 each 31211 131 298 Front Hub w/ABS $83.89 each 31211 128 423 Prot Shield $ 2.09 each (optional)

Hope this helps,

Pete Read
'88 M5