I have been hearing a rattling sound from behind my dash of my 2001 ZR2 Blazer. I suspected the brake booster, so I decided to change the rotors, pads and fluid to see if the worn down pads and old fluid may be the cause. The sound is still there at the time of start up and seems to correspond to the brakes. After doing some research I have found other complaints of a hissing sound, and not rattling. It does feel like I may have a slight loss in braking power.
Has anyone else experiences this or may have a solution?

 

I don't think I've ever heard a brake booster rattle. Check to see if you have any cables or hoses resting on the booster.

Do you hear a hissing, like a vacuum leak where the brake push rod goes through the firewall on the inside of the truck?

To test the booster, pump your brakes 5 or 10 times till the pedal feels rock hard. Then hold the brake pedal down and start the engine. If the booster is working the brake pedal will travel a little closer to the floor.

 

I did the booster test before and it was ok, perhaps it should be better, so I'll do it again and see. Thanks for that. The rattling sound is more like a small grinding sound and yet does not sound like something is really grinding. More of a grinding rattling vibration.

 

Is this when you're moving or will it do it in "P" with the truck stopped?

 

WooHoo, another calgarian.

 

The sound is there on and off as soon as it starts and on and off while driving and in park. Most times it stops when I have the brakes down then it will continue.

Yes it is nice to see anouther member from Calgary, how are you doing?