Whats up with my RS125 rear brake? PLEASEEEEEEEEE

[sunbear]

Hey peeps

My rear brake on my rs125 isnt working. I have tried new pads, new caliper, bleeding and a whole new rear, which worked for a couple of days then started going spongey. After a week i had no rear brake again. There's no sign of fluid leaking from anywhere, including the reservoir and the brake itself. Any ideas?????

Cheers

[bidman]

Sounds to me like the brake hose is expanding or has a leak, try replacing with a braided hose and see if this fixes the problem, Dan
____________________
Don't ride it, RAG IT!!

[sunbear]

It already has braided hoses, and there are no leaks i can find anywhere

[bidman]

Hi, well the only thing i can think is your gettin air into the system sum how, or that the hose is expanding under the braids where it isn't visible. Strip the system down, and get everything pressure tested for leaks or defects, Dan
____________________
Don't ride it, RAG IT!!

[sunbear]

Sounds all good to me mate, cheers

[Kickstart]

Hi

Braided hose cannot really expand under the braiding. The stuff under the braiding has very little burst resistance at all without the braiding.

The RS rear brake is a total pain to bleed due to the position of the brake light switch banjo bolt. They are a pig for collecting air there, but it it works for a few days then that is unlikely to be the problem.

I would suggest that you check the seals in the caliper and master cylinder carefully. The master cylinder has a large outer seal which can hide any fluid leaks for a while. Brake caliper piston seals can cause the brakes to be very spongy when knackered (and again the rear caliper has a decent weather seal which would also camoflage any signs of fluid leaking.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[bidman]

[Gazdaman]

Only think you havn't played with is the master cylinder...

Gaz

[Knowlsey]