My 2010 318 M Sport tourer (E91) recently had its rear discs, brake pads, and parking brake shoes replaced. After reassembling everything, I still can't get the parking brakes to engage correctly no matter how much I try. The specifications provided are for the outer diameter of the discs, not the internal diameter of the parking brake drum, which is something I noticed when I purchased aftermarket discs. I have my doubts about how small the inner diameter should be.
Disc outer diameter and disc thickness 300x20 are the only internal dimensions provided by Real OEM, which caught me off guard. My Hayes manual indicates that the drum's internal diameter can be 160 or 180 mm, depending on the model.
The old discs' dimensions are as follows: an outer diameter of 300 mm and an inner diameter of 160 mm for the drum. In order to have the supplier measure the internal drum of stock they have on hand, I will be returning to their location tomorrow.For the sake of checking, I will not remove mine again. It seems like the parking brake doesn't have enough adjustment, but I think it's because they're 180mm versions.
By carefully following Haynes's instructions, I was able to adjust the parking brake and confirm that pressing the hand brake does in fact move the parking brake shoes, ruling out cable breaks and other possible causes.
Even though they were worn to the metal, the old parking brake shoes were more efficient than my brand new shoes and discs!
I hope this doesn't force me to purchase an OEM rear disc from BMW; has anyone else experienced this issue?
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Joined: Mon Apr 06, 2026
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Joined: Mon Apr 06, 2026
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The desired inner diameter for the parking brake drum of original part number 34216855007 is 160.8 mm. Used specifications for ATE.
One possible metric is the outer diameter of the disc hub. As a result, the outside diameter must not exceed 180 mm, and the wall thickness must not exceed 10 mm.
One possible metric is the outer diameter of the disc hub. As a result, the outside diameter must not exceed 180 mm, and the wall thickness must not exceed 10 mm.
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Thank you so much. The dimensions shown in that diagram match up perfectly with my previous rear disc/drum setup. To find out the precise dimensions of the replacement, I will contact the manufacturer tomorrow.
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Is it mentioned in the Haynes manual to loosen the bolts at the end of the handbrake before making adjustments at the hub?
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It does, though it was a pain to get the spring to latch, which I eventually managed to do.
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Possibly, but I'd wager that you have the sport brake components on hand.
This occurred to me when I tried to get replacement brakes from Realoem using both my registration number and a part number.
I messed up the calliper measurement, but the pad still fit; it just didn't cover the entire disc.
This occurred to me when I tried to get replacement brakes from Realoem using both my registration number and a part number.
I messed up the calliper measurement, but the pad still fit; it just didn't cover the entire disc.