I am having trouble getting my ex Jag XJS brakes working right on my Hotrod. The front/rear balance is wrong and the pedal without servo needs far too much effort. They seem to work pretty well with the servo.
I question whether I have got the brakes pipes installed right. I have a diagram from (I think) the right vintage which definitely shows the front brakes operated from the far end master cylinder port and the rears from the inner port which is exactly what Enoch says in his post 05/09/2014. However, as far as I can see from the diagram he posted, it is the other way round.
Also I am a bit confused by the markings on the cylinder. The inner port has a P marked – is this Primary? – it certainly operates first when the plunger is pressed. The end port is marked S (secondary?) and operates later. Shouldn’t the primary braking be on the front? Could this be my balance problem?
The master cylinder operates freely on the bench.
The PDWA (on the bench) allows fluid through.
All callipers seem free and all pipes are new.
The servo obviously works but with the master cylinder disconnected the foot pressure needed to operate it without vacuum is considerable – is this normal?
I am considering removing the PWDA for simplicity and it may be causing my problems. Lots of conflicting views about whether it does any more than provide the warning light and it seems that many XJSs just didn’t have them. Got the following from a Jag Workshop online manual:-
“NOTE The brake system pressure differential warning actuator (P.D.W.A.) unit has been deleted. This deletion in no way affects the performance of the braking system as the conventional split system is retained”
Any answers to my questions or ideas would be greatly appreciated.