2001 4.6 THOR - WABCO 'D' ABS system.

The brakes became soft. I checked red for leaks, bled the system and replaced the brake pressure pump accumulator (STC2784); the brakes still needed pumping.

On braking, 3 warning lights illuminate: ABS, Handbrake & Traction Control, so I replaced the Wabco ABS control module ECU (SRD100501), still no luck.

My next thought is to replace the ABS Booster Pump & pressure switch (WML 70749). These are expensive, even second-hand, so any other ideas would be welcome 👍

If I do need to replace the Booster, does anyone know an outfit that refurbishes them?
 
2001 4.6 THOR - WABCO 'D' ABS system.

The brakes became soft. I checked red for leaks, bled the system and replaced the brake pressure pump accumulator (STC2784); the brakes still needed pumping.

On braking, 3 warning lights illuminate: ABS, Handbrake & Traction Control, so I replaced the Wabco ABS control module ECU (SRD100501), still no luck.

My next thought is to replace the ABS Booster Pump & pressure switch (WML 70749). These are expensive, even second-hand, so any other ideas would be welcome 👍

If I do need to replace the Booster, does anyone know an outfit that refurbishes them?
Firing the parts cannon is an expensive way of fixing things.
Does the brake pump run? It should run every 3 to 5 depressions of the brake pedal. If it doesn't run then check the fuses but it's likely that the pressure switch has failed. The switch is hard to come by but was used on other vehicles including SAAB and Jaguar.
You say you bled the brakes, did you follow correctly the procedure in RAVE? If not you may have made matters worse.
Diagnostics may help.
 
Following Datatek and another couple of very helpful guys’ guidance on RRnet, yesterday I bled the brakes with a friend according to the P38 (0ddj4rl3) YouTube video helpfully recommended by PWood999. In doing so, I realised that, despite being dealer serviced for the first ten years of its life, the system had never been bled properly, as the top nipple of the three on the block beneath the fluid container was embedded in factory polyurethane foam and, once cut free, appeared as new. Quite a lot of air was expelled from the system through all the nipples.


The good news is that my brakes now work properly, but – as always – there’s a catch: the three warning lights still very briefly come on when the brake pedal is pressed. As it drives and brakes fine (currently), I plan to repeat the bleed to remove any remaining air; if the lights still come on afterwards, I’ll fit a new accumulator.
 
Following Datatek and another couple of very helpful guys’ guidance on RRnet, yesterday I bled the brakes with a friend according to the P38 (0ddj4rl3) YouTube video helpfully recommended by PWood999. In doing so, I realised that, despite being dealer serviced for the first ten years of its life, the system had never been bled properly, as the top nipple of the three on the block beneath the fluid container was embedded in factory polyurethane foam and, once cut free, appeared as new. Quite a lot of air was expelled from the system through all the nipples.


The good news is that my brakes now work properly, but – as always – there’s a catch: the three warning lights still very briefly come on when the brake pedal is pressed. As it drives and brakes fine (currently), I plan to repeat the bleed to remove any remaining air; if the lights still come on afterwards, I’ll fit a new accumulator.
How often does the pump run? Should be every 3 to 5 pedal presses. If it runs more often then it's likely the accumulator is shot.
 
I've just checked this Datatek, and the pump runs immediately for a very brief period each time I depress the brake pedal. Baffling, because when this issue - soft brakes and triple warning lights - first appeared, I had my local garage, who were renewing the front wheel bearings, install a new accumulator?
 
I've just checked this Datatek, and the pump runs immediately for a very brief period each time I depress the brake pedal. Baffling, because when this issue - soft brakes and triple warning lights - first appeared, I had my local garage, who were renewing the front wheel bearings, install a new accumulator?
Maybe they just billed you for a new one but forgot to fit it. :rolleyes:
 

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