Brake Reservoir Rubber Diaphragm replacement

[Lee]

Is it necessary to replace the black rubber gasket (diaphragm) every time you open up the reservoir?

 

[DeanR]

No, Clean it (denatured alcohol), dry and install.

 

[beemerphile]

Only if damaged (which is unusual).

 

[Ron]

Any spare brake master cylinders laying around? The 1100 clutch and front brake master cylinder diaphragms have the same part numbers.