Back brake on carbon frame problem? (Mechanical question)

mrbungle

Well,

Carbon frame: Back brake came a bit loose, had been tightening it but was coming loose again.

I took the retaining nut off the back and removed the brake.


There was what I think was a build up of dark gray/black gear behind the washer in between it and the frame.

What I want to know is: Is this black stuff some compound that goes in between the washer and the frame to protect carbon on metal or can I clean up this gear and tighten the brakes back in place.
ie: washer directly on frame or do I need some kind off buffer.

This black stuff was caked! Could have been dirt but was about 3mm thick which led me to believe it was squirted or place in there originally.

Thanks.


photo-30 by circaL8, on Flickr

bcmf

I reckon its just crud.When you put the brakes back on put some tape over the hole at the back of the brake where the retaining nut goes and it will stop a lot of the crap getting back.
Give the carbon a good clean as well as the bolt and stick a bit of grease on the thread.Put the lot back together and put the tape over the hole.

gman2k

Probably just assembly grease gone black with age, crud etc.

dancecatz2000

Put a bit of thread lock on the threads to stop nut coming loose. it also looks like the frame insert is on the thread of then rear brake, you might have to get this epoxed back into the frame,