back brake not working

[peterekins]

Has to be master cyl not presurizing fluid, try pumpimg lever a few times, if that worked better, its prob the cylinder seals, easy fix.
If it was the calliper,Hydo brakes don't seize off they always seize on.

[Freeloadeur]

This is the brake light sender unit and looking at the diagram I notice it plugs into the loom somewhere deep in the frame. I'd try and trace it back to see if its come unplugged or become corroded.

PhotoDesk130207122432.jpg (400.3 KiB) Viewed 661 times

Mind you it seems a huge coincidence that the brakes don't work AND the light, it did sound like the master cylinder has a problem, the linkage is sind isn't it?

[daytona-supersport]

You'r not getting pressure so no brake and no brake light switch.
So, leak somewhere. Air getting in /fluid getting out. It does not take muck of a leak at either master cylinder or caliper to loose all pressure. Air compesses, fluid does not.
First port of call = master cylinder leaking. Most common. Inspect / repair / test.
Second = caliper seal leaking. Inspect / repair / Test. Even with worn pads the brake should still function.
Third = Damaged brake line. Inspect / replace if required.

Don't muck about with dodgy brakes. Remove, strip, clean, replace seals if required and make sure pads are in good order. You need brakes that you can trust 100%.

Do remember that badly worn pads not only work inefficiently but also allow the caliper pistons to come out much further and the master cylinder piston to go through a longer stroke.

[knobbly]

This is the brake light sender unit and looking at the diagram I notice it plugs into the loom somewhere deep in the frame. I'd try and trace it back to see if its come unplugged or become corroded.

PhotoDesk130207122432.jpg

Mind you it seems a huge coincidence that the brakes don't work AND the light, it did sound like the master cylinder has a problem, the linkage is sind isn't it?

Well as daytona-supersport says could be a leak. If there is no pressure in the fluid then the switch wont work either. Just check at the obvious first to try and pin point the problem before taking things apart.

[hodgerydoo]

Thanks everyone, day off tomorrow to try and fix, will work through all suggested checks.

[hodgerydoo]

Spent the morning going umm, urrm :S :dry:, a couple of taps with the fine adjustment tool then took it to a bloke who knows what he's doing! As i clearly don't.

[Freeloadeur]

Spent the morning going umm, urrm :S :dry:, a couple of taps with the fine adjustment tool then took it to a bloke who knows what he's doing! As i clearly don't.

Fine adjustment tool...?

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Hope it's fixed (and cheap) let us know what happened.

[hodgerydoo]

Yep that's the "fine adjustment tool", turned out it was just air in fluid, needed bleeding so will have to learn to do that myself.