After installing disc brakes ad bleeding the brakes on my (new to me) 2002 e825, I’ve twice noticed significant brake fluid leaks. The first time, I noticed some leaking at the connection of the new front brake lines, so I tightened those and that doesn’t seem to be the issue anymore. This time, I noticed the pooled brake fluid seems to be directly under the master cylinder. When I looked inside the reservoir, the front portion still has some brake fluid, but the rear is completely empty, and if I wiggle the reservoir a little the rear gasket squishes a little like a wet sponge. So, I think that gasket is the source of my leak.
Can I simply replace that gasket, or do I have to replace the entire master cylinder assembly? The parts catalog shows the entire assembly, but not its components. If just the gasket can be replaced, anyone know what I need to get as a replacement? Thanks.