M211 Brake Problem- Any ides?

From: Joe Garrett (j.garrett@gte.net)
Date: Fri Jun 08 2001 - 17:20:56 PDT


My M211 has a weird brake problem. When you apply the brakes, they stay on
for a while. The brake lights stay on, too, so there is pressure on the
whole system, for about 5 to 10 seconds after the brakes are released.

I put a new booster pack on the truck and this seems to have made the
problem worse by making the brakes work better. The reason I replaced the
booster pack is that if you opened the air tanks so there was no air boost,
the brakes wouldn't do this and the truck was driveable. This "implies"
that the problem is not the master cylinder check valve, and that it resides
in the air system.

This same thing happened on one of my M35's, too, but I just replaced
everything; booster, master cylinder and finally all the wheel cylinders
(the rubber boots were in pieces). I don't know which of these items fixed
the problem. It just went away.

Anybody have any idea what is going on here? It is not the brake lines.
They are fairly new, and they are downstream of the brakelight switch.

Joe Garrett
cell 425-344-1402



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