Spindle Eccentric Bolt - BMW Substitute

[q20v]

*** Update - See Audi replacement part numbers in the posts below. You don't need to buy BMW parts! ***




Hey guys,

I found what appears to be a near identical replacement option to the rear spindle eccentric bolt (NLA).

The NLA bolt in question (Item 21 - 8A0 501 387 C)




I was looking at refinishing mine since they have a bit of surface rust, then thought to explore BMW options. After a rudimentary google search it occurred to me that I own a BMW and coincidentally have the same mental condition as I do with the Audis. Chronic Partswhore... quite serious, I should get checked out. Anyway, I had the BMW eccentrics in my basement already (yes, that's how bad it is)

OE Audi Parts:

Eccentric bolt M12x1.5x95: 8A0 501 387 C (I measured 94mm length, no big deal)
Keyed eccentric washer: 8A0 501 385 A
Self Locking Nut: N 90635001


BMW Parts:

Eccentric bolt M12X1.5X98: 33321095102
Keyed eccentric washer: 33306786186
Self Locking Collar nut: 33326760668 (Can use the Audi Nut since it's the same size - M12x1.5)

Comparison pics:


Audi washer (35mm dia):


BMW washer (33mm dia):


Audi length (94mm measured):


BMW length (97mm measured):


Note: Thread length is shorter on the BMW bolt (25mm vs ~33mm) however the pics below show that it's not an issue.

Installed:





The diameter of the eccentric is 2mm smaller, so it's not as tight of a fit in the lower control arm, but it will provide that eccentric movement when you rotate the bolt head by putting a bit of pressure against the spindle (inboard or outboard). Recommend inboard pressure on the spindle while torquing the bolt as cornering loads are higher in this direction. Alternatively, if you're a keen welder, you could add a 2mm strip of steel to fill in the gap on your control arm.

While it may be very evident, you need the BMW washer to go with the bolt, as the pattern on the ID is different from the Audi bolt.

Obviously not a smoking gun solution but pretty close.

Hope this helps,

Barry


Disclaimer:
- For those concerned about the bolt shifting due to the 2mm clearance, once torqued to spec I wouldn't anticipate this happening since even the Audi eccentric has a bit of play in the control arm. The clamping force provided should be adequate to react the anticipated in-service loads for a daily driver.
- I have not tested this setup yet so all information presented above is to be used at your discretion. I'm merely sharing info that I've found.