Brake Servo Problem??

[roseytvr]

Since changing the engine, and vacuum for the servo I have noticed a brake fade in that at first attempt all is fine but if I come off the brakes and straight back on there is a drop in efficiency as if the servo is leeking. Given the difficulties involved in replacing the servo can the collective advise on how I go about identifying the fault. Below you can see the new set up for the servo - the two small pipes disappear off to my very nice JE Xover manifold


How would I go about checking I am getting enough air for the servo?

Assuming I am getting enough air and given the above symptoms anything else I should check before I replace the servo?

Any comments gratefully received
Ian

[Brummmie]

If the pedal becomes hard, and its not stopping then its probably a servo problem, look for a kinked vacuum pipe or an air leak.
I have only one pipe from one of my 8 throttle bodies and have no problems.

[tvrgit]

you could try disconnecting the vacuum pipe at the servo, and fitting a vacuum pump (the kind of thing you use to bleed brakes) - that would tell you (a) if the servo holds vacuum (if not then you might have a damaged diaphragm or casing) and (b) if the pedal is any better when proper vacuum is applied - that would isolate "servo" from "rest of system"