Brake booster question
 

My 2001 Ranger has had a long, soft pedal and weak brakes for quite
a while. The dealer replaced the shoes, pads, master cylinder, and
the ABS unit. Four dealer visits later, the brakes still suck.
Now they want to replace the booster. I don't see how a bad booster
could cause long pedal travel, though. Can't they just put a vacuum
to the booster and if it holds the vacuum, that means it's working?
Also, does anyone know how the front to read proportioning valve
works on a 4x4 Ranger with 4 wheel anti-lock? Does it compensate for
weight in the bed? If so, how?
Thanks,
Henry

A nonfunctioning booster e.g. with no vacuum will will result in a short, hard pedal. I have seen vehicles with the same problem as yours and have replaced all the items that you have without success, but have not changed the booster because of high cost. A proportioning valve limits hydraulic pressure to the rear brakes and is supposed to keep the rear brakes from locking up. Most are not well designed; they either don't work or don't keep pressure low enough to keep the brakes from locking on an unloaded vehicle. Better to have ABS to keep the brakes from locking.

"Henry H. Hansteen" wrote:
>
> My 2001 Ranger has had a long, soft pedal and weak brakes for quite
> a while. The dealer replaced the shoes, pads, master cylinder, and
> the ABS unit. Four dealer visits later, the brakes still suck.
> Now they want to replace the booster. I don't see how a bad booster
> could cause long pedal travel, though. Can't they just put a vacuum
> to the booster and if it holds the vacuum, that means it's working?
> Also, does anyone know how the front to read proportioning valve
> works on a 4x4 Ranger with 4 wheel anti-lock? Does it compensate for
> weight in the bed? If so, how?
> Thanks,
> Henry

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Mike Walsh
West Palm Beach, Florida, U.S.A.