Hello,

I have a problem with my brakes.. they work fine when im at slow speeds, but if im traveling over 40 km/h they stiff up, and i cant press the breaks down, its really stiff. if i keep on pressing it, it will slowdown alittle, and i here a computer type buzzing noise thats loud, (it sounds like its coming from the front driver side) then when the buzzing stops, the breaks are working again. Please if you can help, that would be great!

96 blazer 4door, 4wheel drive.

 

i dont know right know about the brakes. but the grinding nose is it like a vibrating can you feel it on your foot when you drive ???? cause if you can it could be a hub assembaly.. mine is doing the same thing and thats what i had to do. let me know

 

Is the abs light on if it has abs? Sometimes if the wheel sensors are going out the brakes will be hard to push at times then they will release and be fine.

 

Sounds like a bad brake booster....at lower speeds you have more vacuum and as engine RPM's increase you have less.

So, with less vacuum it would be harder to press the pedal down...I would be checking for a leak on the brake booster.....

Do this first.....run the truck for about 30sec at idle and shut if off, then quickly remove the the round black valve in the brake booster and listen for a hiss....did you hear a hiss??? If no, then its the booster.....if yes, then read on.


With the check valve out of the booster (with rubber hose still attached) start the truck (it will run kinda rough) put your finger over the valve and see if there is vacuum....when you put your finger over the hole the engine should run pretty close to normal.


After that test pull the other end of the hose off of the engine, now on the end that you took off the engine you should be able to suck through the line, but not be able to blow through it. If you can blow through it then replace the one way check valve.

 

I agree with Frog with one adjustment. After you run the truck 30 sec and turn it off, you should be able to wait a few minutes, then pull the check valve out of the booster and hear air rush in. If not, either the check valve or the booster is bad. I'd try the check valve first for obvious reasons.

Bill

 

Thanks guys! i have not tried any of these on my truck yet.. but i'd just like to add in, My truck was recently vandilized and they cut up a bunch of cords, including my trucks Computer, I took it to a mechanics and they fixed everything.. I was just wondering if maybe something could have gone wrong when they were fixing it?

 

Anything is possible.....the brake system is fairly basic as far as operation is concerned.

Now, the ABS is a whole other story.

I would check what was advised first....then let us know what you find.

 

2001 s-10 blazer pedal pulsates back at you abs lite is off and on, noise sounds like a vacuum leak. useually happen's at low speed it always stops but this morning leaving store got to street didn't wont to stop freakin scary man gonna try frogs advice

 

The buzzing noise is the ABS. Mine does the same thing. I don't use mine as a daily driver or at high speed highway driving so I unplugged the connectors on the ABS box under the hood.

It could be the sensors or the high-dollar ABS unit itself. I don't know of a test other than first clean the ABS sensors. If it still make the noise, replace them. If it still makes the noise, it's the ABS module.