Bleeding Brakes

[JohnM]

Hi, can anyone shed some light on my brake problem. I have a 1985 307D which defies all attempts to bleed the brakes. After bleeding I have a good pedal but as soon as I start the engine the pedal just goes down halfway to the floor. I have pushed about 2ltrs of fluid through the system and cant get any air out. The pedal will pump up but just goes down again.
I would be grateful for any help before I go mad.
Thanks.

 

[Bolide]

The servo or the master cylinder (or both) are US. As it's a diesel the servo must be powered in some way. Sounds like a job for a specialist

Nick Froome
www.w124.co.uk

 

[JohnM]

Thanks for the info, I forgot to mention that the master cylinder has been replaced. The servo is powered by a seperate vacuum pump, this appears to be working ok.

 

[Sprint'n'Go]

Sounds a lot like a the master cylinder. Was the replacement a new or secondhand item? A secondhand one from a vehicle of this age must be as suspect as the one removed from your own vehicle. I would try clamping off (using proper brake hose clamps) the brake hose/s to the rear brakes to rule out any faults with adjustment/leakage (I once came across a vauxhall that was sucking air into a rear cylinder but was not leaking!). If this doesn't help I would then seek out a secondhand servo and as a last resort get a replacement master cylinder (i.e take it back to whoever supplied it)

 

[JohnM]

Thanks, The master cylinder is a new unit, but I will certainly try clamping the rear brake hose.

 

[Juddian]

Hi john Steve has a good idea about clamping the pipes, remember bleeding Land Rover brakes years ago (all drum) and struggling like hell until i removed the drums (will work with discs also) and held the slave cyls in tight with G clamps. Sounds drastic i know but i would still be bleeding them 30 years later if i hadnt done it. Good luck....Brian

 

[Sprint'n'Go]

Hi john Steve has a good idea about clamping the pipes, remember bleeding Land Rover brakes years ago (all drum) and struggling like hell until i removed the drums (will work with discs also) and held the slave cyls in tight with G clamps. Sounds drastic i know but i would still be bleeding them 30 years later if i hadnt done it. Good luck....Brian

Good solution but I don't have that many G clamps (6 for a LWB):idea:

Been there, done that!