Mystery Brake Pad Wear

TWO

Zorg Guru (I)
Joined
Dec 5, 2011
Messages
254
Location
Chelmsford
Model of Z
Z Sport Roadster 2.2
Please can anyone advise on the strange wear pattern on the rear discs on my Z3, 2.2.......the same on both rear discs! :-s

As you can see the discs have worn from the inside of the diameter and on the reverse side have worn by a similar width but from the outside diameter of the disc........as if the calipers are twisting.

There was flexing of the caliper when I levered the spring clip out with a screw driver using the hub as a fulcrum, BUT all fixing points appear to be absolutely rigid. #:-s

I will clean every thing back to 'new' when I replace the pads; but in the meantime please can members advise on the cause............is it in any way effected by a leaking brake servor?





Many thanks
 

HornelZ3M

Zorg Addict
Supporter
East Anglian Crew
Joined
Dec 4, 2011
Messages
939
Location
Raglan. South Wales
Model of Z
Z3M Roadster
Have you ever thought of cleaning the discs in the past to prevent the probable seizure of them, which looks apparent. :-s
 

EnthuZiaZT

Zorg Guru (V)
British Zeds
East Anglian Crew
Joined
Dec 6, 2011
Messages
4,696
Location
Heacham Norfolk
Model of Z
Z4 28i Msport
Yes, Two, Like Hornel, I think that one of the brake calipers has seized. Best thing to do is to take them apart and give them a really good clean and ensure all the pistons are moving evenly in the bores and the slides are working. :-bd
 

peteslag

Zorg Legend
Joined
Dec 7, 2011
Messages
540
Location
Shifnal, Shropshire
Model of Z
Z4 3.0 SE
That type of disc wear is very typical of a partialy seized piston. Sometimes they can sit at a slight angle, causing the disc to wear un-evenly. As said before, you need to do a full refurb your brake calipers and more than likely replace pads AND discs. If you fit new pads to those discs it will not work properly and very probably ruin your new pads. :-q
 

Warrior

Dedicated Member
Joined
Dec 7, 2011
Messages
151
Model of Z
3.0i sports automatic
Is this the sort of thing that should have been picked up during a full service and MOT at a specialist BMW independent?
 

Titan

Moderator
British Zeds
Joined
Dec 4, 2011
Messages
1,409
Location
North North Yorkshire
Model of Z
sDrive35i
Warrior said:
Is this the sort of thing that should have been picked up during a full service and MOT at a specialist BMW independent?
I would have expected to see a "worn"ing for uneven disc wear ;)
The calipers and slides certainly need a good overhaul and clean but that may not solve the problem.
The pistons may still be sticking in their bores so you need to check them for free travel.

If it's going to be a DIY job, you may as well change the brake fluid at the same time remembering to remove the clutch slave cylinder and invert it to bleed properly.
 
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