Archived No Brakes, abs light on

[qkoop]

I was driving in a parking lot last night and pushed the brake pedal and the pedal was hard and i had to stand on it to stop the truck. It's like there was no vacuum. I checked and cant find any vacuum leaks. it has did it once since,but i rev the moter alittle and the brake and abs light go out and brake are o. k. Never did it again but i am scared to drive it in case i step on the brakes and there not there. thanks in advance

 

[bmoeller]

What year is your truck? If it a '97 or later, it doesn't use a vacuum booster.



If it is an older one, then it could be the booster or some other vacuum leak (bad pump?) that would prevent enough assist. Don't if the ABS would cause it or not, other than maybe a valve that is part of that system is sticking/stuck.



Does it do it (almost) every time?



When is the last time you changed the fluid?



The way I tested the Vac. booster on my Ford, was, I disconnected the line to the booster and started the truck after attaching a gauge. I had a blown diaphram in it and replaced it.



Before the new booster, I had only 6"vac. Aftrer, I had 26.

 

[qkoop]

Truck is a 94 and its done it twice and only while idleing around parking lots. Could it be abad check valve on vacuum pump?

 

[B.G. Smith]

Brakes

Don't know if there is a check valve in the pump but there is one in the brake booster. You can check it by shutting off engine and waiting a couple of minute then apply the brakes, there should be enough vac. left to apply brakes one time. Could be a line collapsing or a leak somewhere. bg

 

[Timinator]

I have a '95 and I experienced that problem last winter. The pedal was hard and the BRAKE light came on. It happened twice, but only when the engine was cold after sitting out overnight.

I found that my vacuum line from the vac. pump had gone soft from oil contamination. The vac. pump seals had started to deteriorate and allowed oil to get into vac. hose.

I bought a new piece of hose from a local shop, and a vac. pump gasket from local Dodge dealer. I bought new vac. pump seals from TDR member CPFF. The seal and o-ring were only $20, if I remember properly.

It took about 4 hours to take apart and reassemble and the improvement is dramatic. It feels like new.

My check valve was good, but I replaced it anyway - only $10.

 

[qkoop]

That sounds like exactly whats happening. I will do a search for that member to try and buy the pump rebuild kit. And my hoses are original so they are probly shot. Thanks for the feedback guys. Without getting into your heads for your input i would have started at the booster and needlessly replaced good parts. I love TDR you guys rock!