Spongy brakes.

[Mk5swbhighroof]

A bit odd. My brakes feel a bit spongy in use, pumping the pedal whilst breaking having very little effect. When stationary however (with the engine running, the booster is working) pumping the brake pedal twice, makes the pedal rock hard, and the brakes much more responsive (when rolling off the hand brake) The brakes work ok, and there is no loss of fluid from the reservoir, and no leaks that I can find.

Thoughts? What have I overlooked?

[gotgcoalman]

Few ideas...........

Rear self adjusters not working (slave cylinder having to push further than normal)
Fluid has absorbed water.
Fluid is blackish when cracking a bleed nipple (been over heated or has contamination from a failing flex pipe)
load sensing valve sticking.

I might think of more over night.

Servo is fed from the oil pump on the back of the alternator and if that failed it would make the brake very hard with vastly reduced brake effect.

[Mk5swbhighroof]

Thanks coalman. I don't think it's the adjusters, because I had those out and cleaned when I changed the brake shoes recently. I'll check the fluid, to be honest, it may be a good idea to change the fluid anyway. What is baffling me is the difference in the feel of the pedal when stationary (but with engine running) versus when underway.

[V184]

is there a difference with the handbrake on ?

[MinorMatt]

Play in wheel bearings?

[joinerman]

M\y first thought as well Matt

[gotgcoalman]

brakes being good when stationary (hanbrake applied) made me think it was a rear brake issue.
Wheelbearing causing brake fade should be felt through the pedal surely?(abs feeling on a non abs system)

1 or more flexi pipes buldging under pressure also might be something to consider.

[vanfox]

Buy a pair of brake hose clamps, ebay, cheap, and close off a brake / axle in turn till you find a difference. Could just be all your rubber hoses need replacing.
How long should brake hoses last?
How many 15 yrs old vans are still on the original pipes and discs?