So there was me thinking my PP V4 was the first Multi (of the 4 I’ve owned) that had a decent back brake. I use the back brake a lot under 30 mph to steady the bike in traffic (IAM training) so when faced with a need to filter through 20 miles of traffic jam on the M40, I confidently worked my way through the tailback. About 5 miles from freedom a car edged across so I went apply the back brake and the pedal went all the way down and no braking. So I edged forward gingerly through the remaining five miles to the front of the queue using throttle and front brake only. A few miles after the traffic had cleared I tried the back brake again and it had come back. I’ve had the same happen on a hilly trip when using the back brake down a 1:4 hill. My theory is that the brake fluid is boiling. Anyone else had this problem and would you consider it requiring higher boiling point fluid or a fault that needs to be fixed? I know some will say ‘stop using the back brake so much’ but that doesn’t answer the technical problem that is happening more regularly (I guess once the fluid has been cooked it’s more prone to recurring?) and I want a fix for. A mate had the same happen on his triumph going down Stelvio Pass(!) and that turned out to be a faulty ABS sensor apparently. Constructive advice would be really appreciated.
Your fluid definitely overheating there. Its cooked and most likely needs changing anyway. I would suggest a higher boil point fluid, maybe a race fluid, RBF 600/660 or similar. A worn pad will get hotter too.
Says in the blurb the boiling point is in excess of 300 degrees, Motul 700 (their highest for normal people I think) is 336 degrees so would think that Castrol is pretty high
The Castrol SRF only seems to come in 1L and is £79 while the Motul 700 comes in 500ml and is £29. Motul seems like a no brainer?
