Sinking brake pedal

Post by **PSL184** » Sun Aug 10, 2008 2:54 pm

I'm just looking at the brakes now and I cannot find any leaks, still. However, I have bled the fronts and got a lot of air out. I also noticed that when I press the brake pedal with the cap off the M/C a jet of fluid spurts out - is this normal or a clue to the fault? I am of to bleed the rest of the system now and see how it goes but the pedal is a lot firmer now that I've just bled the fronts....

Post by **bigginger** » Sun Aug 10, 2008 3:05 pm

Perfectly normal re the fountain

Post by **PSL184** » Sun Aug 10, 2008 3:22 pm

Cheers. All bled now and pedal back to normal. Just see how long for I guess?

Post by **bigginger** » Sun Aug 10, 2008 3:53 pm

Fingers crossed

Post by **MoggyTech** » Sun Aug 10, 2008 4:30 pm

But where did the air get into the system if it was OK a while back. Worth flushing the complete system with fresh fluid. Brake fluid is hygroscopic and absorbs moisture. If this boils off under heavy braking, you get O2 in the fluid.

Post by **PSL184** » Sun Aug 10, 2008 7:05 pm

Yeah I don't know how the air got in - It's a complete mystery. Obviously I'll be keeping my eye on things. The fluid was all new as at the time I changed the M/C it would have all been new fluid through then.... Most strange

Post by **bmcecosse** » Sun Aug 10, 2008 9:22 pm

Boiling fluid - would need VERY VERY hot brakes, and can produce water vapour with temporary loss of pedal - but it comes back on cooling. No O2 is produced - where would it come from ??