Brake pedal gets hard

[93 W350 LE]

My brake pedal gets hard if I am on it for more than a few seconds. Like when you lose power and try braking. Seems like I am losing vacuum or something. Any ideas?
Thanks.


Eric

[PToombs]

Tee in a vacuum gauge and see what it's doing. You should have about 22-23 inches of vacuum at idle to begin with. It sounds like the booster may be bad and leaking, but the pump could be getting weak too.

[ellis93]

Mine does the same....when its cold out. Booster has a seal on the inside rod that shrinks and let's the vacuum pass by,that's what the deal is with mine. I'd have fixed it but those that have bought reman boosters have had schity luck gettinga good one,so I deal with it.

[93 W350 LE]

It has happened since leaving Fl and coming to winter in Northern Okla. My brake and abs lights will come on if on pedal too long, but go back off as soon as engine speed goes up. The pedal also softens up if released for a couple .seconds.


Eric

[Tacoclaw]

That little sensor over by your driver's hood hinge is a vacuum sensor, if it senses low vacuum it'll turn your brake light on.