Brake warning light on - pedal stiff ???

[cbuttre835]

Couple of months ago I'd get the occasional brake warning light on in the dash... truck still stopped fine though.

Over the last couple weeks though, the pedal has gotten stiff. Truck still stops you just got to stand on it - really pay attention when you drive. Light is on all the time now. So I've grounded the truck.

I'm thinking it's either the goofy vacuum pump or master cylinder... I don't know of any way to test either, and just hate to throw parts at it till it gets fixed...

How can I test this particular system and figger out just what it is? Sort of clueless here.... :morons::doh:

 

[Bobby@cp]

Prolly the vacuum pump

 

[Patrick Feeley]

:whs: Master cylinders don't go that often on these things. Cheers!

 

[Bugman]

Vacuum pump. When you replace it you will find that one bolt will not come all the way out with the pulley in place. Just remember that that bolt needs to be in its hole in the pump before you place the pulley back on.

 

[Biggreen96]

To test the vacuum pump pull the line off the brake booster and see if it will hold suction on your finger with truck running, if not then pump is bad but id be willing to bet your pumps bad

 

[cbuttre835]

Finally got around to it; vacuum pump it was. I spun the old one with the air wrench; it would hold a little suction. The new one was like a freon vacuum pump.