the recurrent rear brake thread
 

i thought i had bled the brake successfully on my 748s but seems not

i have tried it above the reservoir and in position
i have bled it conventionally and with a one way valve
there are no bubbles coming out and yet there is no lever pressure until i have pumped the pedal 3 / 4 times
then it works really well
i tie wrapped the pedal down and the pedal was rock solid after being left overnight
opened the bleed nipple, closed the nipple, pressed it , solid

but........once i was on my way no feel unless pumped again

am i right in thinking there must be air locjed in the system somewhere and how do i get it out???

aaagggghhh!

[Edited on 2-5-2006 by loverobot]

I had the same problem and i removed the caliper, faced the bleeding valve upwards and bled it like this.

It cured it..

already tried that - did get a lot of air out but not solved!

i am thinking i will need to tie wrap overnight and then bleed a couple of times maybe over a couple of nights

hAVE YOU THOUGHT THAT YOU MAY HAVE A LEAKY SEAL ? ALLOWING AIR IN EVERY TIME YOU PUMP THE PEDAL ?

hmmm
piston seal at caliper end or at the cylinder end? how would i tell and how would i solve?

You might find that you need to bleed the master cylinder before you try pumping fluid through the lines to the caliper.

Get loads of absorbant rag and wrap it around your master cylinder, and over any adjacent paintwork, just below the master cylinder banjo. Then crack the banjo bolt, just enough to let fluid seep out and push the brake pedal down SLOWLY. Hold the brake pedal down when it gets to the bottom, nip the banjo up then release the pedal. Do this two or three times and the chances are that any air in the master cylinder will now be purged. Then bleed your brake again from the caliper as normal to finish the job.

If the symptoms remain your seals may be naff