306 XTDT brake problem

Before Christmas, a slave cylinder on a rear wheel failed and drained all
the brake fluid out of the car. I found this out the hard way - by having
the pedal go to the floor! The garage replaced the failed slave, and the
other rear slave as it was leaking and replaced the fouled brake shoes.
Driving the car home, I noticed excess travel on the pedal, and a hissing
noise from under the dash, whenever the pedal was depressed. The garage had
a look and said the auto-adjuster hadn't taken up and it was much better
for a few weeks. In the new year, I noticed that when the car had sat for
a long time, i.e. over night, the pedal had excess travel, but would firm up
again after one or two applications. The garage suggested the master
cylinder seals may have been damaged when the pedal went to the floor, so I
had it replaced. Now, I'm getting some excess travel again, and the hissing
noise has returned.

I don't know much about brakes, but I do now that it seems to me as if the
brakes are sometimes working at 100% and at others have greatly reduced
efficiency. As it is a diesel and so uses a vacuum pump, I'm wondering if
the pump is failing, and this is causing the loss of pressure.

Any ideas most welcome!

Simon

 

Simon
The vacuum pump also feeds your Turbo actuator so I would also expect you to
be experiencing problems with acceleration also if the pump was
intermittent..
Mike

 

brake servo's knackered
done quite a few the hiss is from the pedal side of it
replace it
unfortunate that its gone now but i've seen a lot of these fail when the
rest of the system has been ok

 

brake servo's knackered

Do servos tend to die altogether, or can they develop intermittent faults?
The problem seems to be exacerbated by cold weather, and the hissing is very
intermittent - i.e. can be days or a week before you hear it again.
Sometimes, instead of a hiss, you hear a "pop" sound, as if a diaphragm has
suddenly moved (or turned inside out), if you know what I mean.

Thanks

Simon

 

i do know and chances are the brakes will be ok for a while but having
driven a car with a failed servo i wouldn't let it lie change it asap