rear brake

[monkeyrocco]

hi all , just done 450 miles today and had rear brake failure 3 times ie no brake at all not leaking fluid at all the pedal goes totaly soft then the next time it may work no pumping involved it just sometimes works perfect then nothing any ideas ?

[Bear of Little Brain]

Sounds like the system needs the brake fluid replaced (just in case you have moisture in the fluid, which could be vaporising at the high temperatures near/in the calipers) and some serious bleeding.

Check these links:

This is "our" thread
http://www.raptorchapter.org.uk/viewtop ... =14&t=2123

Bear in mind my Little Brain ,but this is the Aprilia link with the definitive two-position method for rear brake happiness, IMHO:

http://www.apriliaforum.com/forums/show ... ake-Issues

For completeness, here is the one other link that I bookmarked at the time. Maybe there was a reason, maybe not – the first two are the more relevant:
http://70.40.196.225/raptorchapter/view ... 5&start=15

[shedmonkey]

Ditto on water in thr fluid causing fluid to boil. Also check rear disc isnt warped or cracked and that pistons arent seized causing dragging on the disc.

[monkeyrocco]

thanks for the replies i will replace the fluid again it was replaced last year though, as was the disc ,hose, and master cylinder the year before as it locked up twice hence i dont use the brake a lot. it happened today the first time after only about 10 miles

[Fausto]

Did you get it sorted ?
It does sound like fluid boiling due to overheating. In which case it's likely the brake is binding.
Ride for a mile or two and don't touch the pedal. Then stop and check it for heat. If it's warm or worse then that's your problem.