Excessive pedal movement with servo

[ramthorne]

Hi

I have a 4x4 buggy which has a Discovery servo, all braided brake hose, one pair of early Range Rover calipers and one pair of HiSpec Princess 4 pot calipers.

It has a rock solid pedal at the top of the travel until you start the engine, then the pedal uses virtually all the travel with poor feel. I've changed the master cylinder, bled carefully, checked the servo and scratched my head.

Any more ideas?

[GreenV8S]

I don't know if that mish-mash of bits are all designed to work to the same line pressure, or whether the pedal leverage is correct. There may be a fundamental incompatibility between those bits, and it would be quite hard to prove whether or not this was the case.

On the other hand it may just be spongey brakes because they haven't been bled successfuly. Are there any high spots in the brake lines, master cylinder or calipers which could hold an air pocket? All calipers being bled from the top?

[ramthorne]

I'm in the process of having the servo/master cylinder repositioned to level it as it was tilting forwards. The pedal and linkage is also being changed as although the leverage was very close to the Disco it was slightly off cam (if that makes sense)at fuller travel. The split for the rear calipers is higher than the feed pipe and calipers, but only slightly. All calipers have the bleed screws in the right place.

My thinking was that if it were trapped air then it would also show when the servo was not operational, do you think this may not be the case?