• Welcome, Guest! We hope you enjoy the excellent technical knowledge, event information and discussions that the BMW MOA forum provides. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please click the 'Log in' button above and enter your BMW MOA username and password.

    If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the discounts and benefits the BMW MOA offers?

1988 K75 Low Seat: Front Master Cylinder or Just Piston

tinytrains

Still plays with trains.
My front master cylinder has been leaking for a while. I pulled out the piston today and took a look inside. there are some small pits on the bottom of the cylinder. I have smoothed them off with 600 grit paper.

So the question is: do I need a whole new front brake master cylinder? Or just a new piston.

Thanks,
Scott

pits.jpg
 
I'd be looking for a new cylinder. Those pits look too deep to sand or hone out, and eventually they will destroy the seal on the new piston.
 
Thanks Don. That was my suspicion, and no point spending $70 on a piston and then another $200 on a MC with a piston.

The damn thing is only 23 years old! :usa
 
New MC installed. Despite much flushing of the fluid, I had trouble getting the air out of it. So I took a syringe (no needle) stuck it over the hole in the bottom of the reservoir and pulled up the plunger. This sucked the air right out! A few strokes of that, an the lever is nice an firm. :clap
 
Back
Top