P38 ABS Pressure Accumulator

Nice easy fix this one.

Symptoms:

1)First thing in the morning the brake pedal goes almost to the bottom and barely stops the car moving.

2)You can hear the ABS pressure pump running, once it stops - the slightest touch of the pedal makes the pump run again. (ultimately wearing the pump out)

3)Brakes seem a little spongy and have about 1” of travel on the pedal

Fix

First you need to de-pressurise the system - do this by pressing the brake pedal 30 times with the ignition off.

Now clean the area around the base of the accumulator to prevent dirt dropping into the master cylinder.

Then get a chain wrench or oil filter strap and undo the black dome. Make sure no dirt drops in the exposed hole.

I filled the new accumulator up with brake fluid and then quickly screwed it on and then tighten it up quite hard.

Start

Start the car up, you should hear the pump run for about 30 seconds and then stop. Pressing the pedal once or twice lightly shouldn’t result in the pump running.  

Check for leaks around thread

Test drive

I immediately noticed that the pedal feel was very firm and brakes worked much better with only a light touch of the pedal.

And next morning I had good pedal feel and they work perfect now.

On UK cars, the accumulator is found on the offside near the coolant expansion tank: