Topic: Front Brake CB550

[Sdsbassist]

Hey all. 1974 CB550. Last thing before she gets on the road.

Front caliper was sticking, but master was pumping fluid. Been down this road and thought I was on the right path.

Disassembled caliper and put in a new seal.

Took out banjo bolt and used compressed air to clear our both holes. Lots of goop in what I believe is the return hole.

Cleaned everything well and reassembled, but now I cant seem to get the cylinder to pump fluid. When I crack the bleeder it seems to hiss air but the fluid level on the master doesn't seem to be going down any.

Any pointers/tips/things I did wrong?

Thanks!

[smee]

Which banjo bolt (hose A or hose B)?

How long ago were any of the brake parts serviced? Chances are part of that goop made it's way into your caliper, but this is more a symptom of the larger issue. Those holes are small and clog easy. You will most likely need to clean it out.

I would go top to bottom and clean/inspect/flush the system completely. If the lines are old (and have had the same fluid in them for a long time), it's going to be at the point of no return.

Start with master -> Free of goop? Diaphragm good? Piston seals good?

Hose B to 3-way joint -> Unobstructed? Free of goop?

3-way joint -> Unobstructed? Free of goop?

Hose A to Pipe -> Unobstructed? Free of goop?

Pipe to caliper -> Unobstructed? Free of goop? Not bent?

Caliper -> Seal is new, Did you lube the seal when you put it in? Free of goop behind piston?


**Don't mean to belabor the point going part by part, but I have found it better than chasing your tail and just pushing the goop in-between parts.

[RAFster122s]

Master cylinder has a bleeding procedure to do before you hook up the hose…