hi all i am Reg in need of help, i have been modifying my disco for on and off road but have got a major brake hang up . i have good used vented front discs with new calipers (not oem) new rear rotors and calipers new master cylinder and servo all new pipes and flexys but when its bled the pedal is good untill i start the motor then it slowly sinks i was told its vacuum so got new vacuum pump no change i have now had 3 servos 3masters and have now gone to defender calipers to cut down pipe work rear brakes are fine i have rigged up calipers off the master with just short pipes and still the same i have had power bleeder and got through 8Liters of dot 4 any one any thoughts .

 

sorry bud i should have said my truck is a discovery 200 tdi with cam driven vac pump

 

Well, could you connect an old school vacuum gauge and see what is going on with that, perhaps pinch off any suspected lines to narrow down source of leaks?

 

Have you checked for good vacuum from the vacuum pump?

 

it is almost unheard of for the 200 TDI to blow a vac pump but at great cost i got a new one and its made on change.

 

So if it has made no change, the vac must be dropping somewhere and at some rate, which we can't see without a vac gauge. So you'll have to attach one somewhere, then you can see changes as you flex various hoses and wiggle connections, etc. The noise of the vac leak might not be able to be heard over the noise of the engine. You could also attach a manual vac pump (Mity vac) and pump things down to see how they hold. But you certainly have thrown a lot of parts at it.

 

i have disconnected the vacuum from the heater unit and run one pipe from pump to servo when i turn of the motor and stab at the brake pedal it takes the standard 5 to 6 stabs to empty the servo that would say that there,s no leeks from the servo so that leaves only the main vac pipe it,s new it,s braided and i,ve been over it the washing up liquid there are no leeks.

 

when there,s no vacuum ie take the main pipe off you get a hard pedal this problem give,s the feeling of over vacuum but the servo has way,s of dealing with that.

 

We dont have any LR diesels here in the US so we have limited experience with this.
A UK forum may be better to help you.

 

i have only seen 1 TDI LR around and it may not have been a factory deal. they could have dropped a cummings in there for all i know.