Have a (probably) vague question, so forgive me....

Have 1996 P38 4.6. Experienced failing Accumulator, at which time normally rock hard brake pedal softened a little (not a lot).

Replaced Accumulator and ABS, SRS, etc. panel lights which had illuminated during braking instantly disappeared. Problem solved. Brake pedal, though, still softer than usual.

Checked system -- leaks, pads, rotors, etc. All fine.

Is it possible that I need to bleed the master cylinder, all wheels too? Some guy is trying to sell me an ABS Pressure Switch - Vacuum Valve. Can this be responsible? Seems odd since Accumulator problem and pedal softening came together. What problems require ABS Pressure Switch - Vacuum Valve replacement?

 

The pressure switch doesn't seem very likely to me. I would bleed the mater cylinder first. Remember there are 3 valves on the master cylinder. Bleeding the brakes is cheap and easy so I would start there first. The Rave manual gives a pretty good breakdown on how to bleed them and in what order.

 

Change out your rubber brake hoses that are failing and do a full 2 quarts DOT 4 brakes flush and you will be fine.