NicD
Registered user
Having faffed about trying to understand the process, here is what I learnt
In addition to standard procedures
1. 100 degrees C bearings slide out. BMW spec 100 degrees. Cheap laser thermometer off Amazon makes it easy
2. Blind puller works better than drift as spacer is tight to bearing. 25mm collet fits
3. Replacement bearings are 6205 C3s with two rubber seals. NSK is like for like (6205 DDU C3)
4. Seat left hand bearing first. Heat to 100 degrees again. Slides in easily
5. Reason to seat left first is that this is the side the axle pulls on when you torque it up (according to BMW technician)
6. I used a Teng 36mm impact socket I have. Has 51mm od
7. Fit spacer
8. Fit right hand bearing. Check spacer is aligned while seating
9. Do not keep driving this bearing home. You need to seat the inner race against the spacer, and the aim is to have the two inner races and spacer move as one. It is correctly seated if inner race moves freely, and while moving freely the spacer and inner race of other bearing move with it
10. If the two bearing inner races move independently of each other, right hand bearing not seated enough. If inner races are reluctant to turn or stiff then right hand bearing has been driven home too far
11. If, like me, you drive right hand bearing in too far, use blind puller to move it back out slightly until you get the correct position
12. Pack seals with waterproof grease and seat seals
13. Fit left hand spacer with grease to seal left hand bearing inner race from water ingress
I'm sure others will add anything I forgot. In case of interest, you can tell if you screwed it up and drove bearings too far - on hard cornering I could feel a rumble through the pegs that has never been there before. Once I re-seated bearings correctly it disappeared
In addition to standard procedures
1. 100 degrees C bearings slide out. BMW spec 100 degrees. Cheap laser thermometer off Amazon makes it easy
2. Blind puller works better than drift as spacer is tight to bearing. 25mm collet fits
3. Replacement bearings are 6205 C3s with two rubber seals. NSK is like for like (6205 DDU C3)
4. Seat left hand bearing first. Heat to 100 degrees again. Slides in easily
5. Reason to seat left first is that this is the side the axle pulls on when you torque it up (according to BMW technician)
6. I used a Teng 36mm impact socket I have. Has 51mm od
7. Fit spacer
8. Fit right hand bearing. Check spacer is aligned while seating
9. Do not keep driving this bearing home. You need to seat the inner race against the spacer, and the aim is to have the two inner races and spacer move as one. It is correctly seated if inner race moves freely, and while moving freely the spacer and inner race of other bearing move with it
10. If the two bearing inner races move independently of each other, right hand bearing not seated enough. If inner races are reluctant to turn or stiff then right hand bearing has been driven home too far
11. If, like me, you drive right hand bearing in too far, use blind puller to move it back out slightly until you get the correct position
12. Pack seals with waterproof grease and seat seals
13. Fit left hand spacer with grease to seal left hand bearing inner race from water ingress
I'm sure others will add anything I forgot. In case of interest, you can tell if you screwed it up and drove bearings too far - on hard cornering I could feel a rumble through the pegs that has never been there before. Once I re-seated bearings correctly it disappeared