New brake master cylinder. No brakes

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CHRIS HILL

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Hi. I've recently had brake peddle creeping to floor. Changed master cylinder for a new Lucas one. Bled brakes through until fluid came through. Gone through 5 litres of brake fluid. Had disco jacked up in air on each corner. With engine running peddle still goes straight to floor. Bled using a pressure blender and two man way. Disco has ABS. Anybody any ideas. Thanks
 
does fluid splash up in reservoir when pedals let up,is there any resistance on the pedal,its quite like;y m/c wasnt the original fault
 
id check the entire system especially were brake pipes are hidden under the body,if the system is good you can get an improved pedal by adjusting m/c rod,
 
Ok. I will check the entire system. Don't think thrers any leak not been losing any fluid. How do you adjust m/c rod. Loads of air came out when bleeding brakes. Most out of near side rear Caliper Much apreciated thanks.
 
n/s caliper and pipe work is were id start, to adjust rod you need to pull m/c away ,have someone press brake pedal down fully,support rod with pliers and turn adjuster out ie anti clockwise a few turns , replace m/c and try repeat if its not enough, if rods adjusted too far out servo will pull brakes on without you touching pedal, you need a tiny bit of free play on m/c rod
 
According to a few previous threads on the same subject ie. unable to remove air from the ABS equipped braking system after replacing the master cylinder, I believe the valves in the ABS modulator must be open to allow fluid to pass and remove air that is trapped in the modulator, and again I believe it will require the use of LRs Testbook or similar.

Not that I would ever have go there, so I wasn't that interested so didn't take notes but the ABS modulator is probably the cause of your problem, u may find the threads on the Forums it's also the same system as some RRCs.
 
discool said:
According to a few previous threads on the same subject ie. unable to remove air from the ABS equipped braking system after replacing the master cylinder, I believe the valves in the ABS modulator must be open to allow fluid to pass and remove air that is trapped in the modulator, and again I believe it will require the use of LRs Testbook or similar.

Not that I would ever have go there, so I wasn't that interested so didn't take notes but the ABS modulator is probably the cause of your problem, u may find the threads on the Forums it's also the same system as some RRCs.
Click to expand...
rrc system is a totally different system than disco ,freelander and defender and is a very much more complicated system to bleed, whiilst its possible some air could get trapped in modulator ive never known it ,or had to use any diagnostic kit to bleed the disco system whether fitting new master cylinder or new modulator
 
jamesmartin said:
rrc system is a totally different system than disco ,freelander and defender and is a very much more complicated system to bleed, whiilst its possible some air could get trapped in modulator ive never known it ,or had to use any diagnostic kit to bleed the disco system whether fitting new master cylinder or new modulator
Click to expand...

There u go then, as I said it's only my understanding from what I've read in various threads and wasn't that interest.
 
It's a new m/c. Will have to take it back. Got it from paddocks. Paid the extra and got a Lucas one. Been at it all day. Used another 5 litres of brake fluid. Peddle still sinks to floor and is very soft.
 
After bleeding system again but with no improvement in brakes. In fact they got worse I remitted original master cylinder. Massive improvement although still had original fault of pedal creeping. New master cylinder is no good. Going to be sent back. Got to wait 2 weeks while manufacturers inspect it.thought Lucas was a reliable brand.
 
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