Chevrolet Repair: 2003 chevy trailblazer brakes, monroe muffler and brake, 2003 chevy trailblazer

Question
The brakes on my blazer do not seem to stop very well, and if I come down a long hill the front brakes heat up and start to vibrate. It feels like the only brakes working are the front. In snow if I hit the brakes even gently the front go into antilock and I just can't seem to stop no matter how hard I press on the brakes. I have put new pads and rotors on the front but that did not seem to make any difference. I just had it to Monroe Muffler and Brake and they said everything seemed ok and that I might be driving the car to hard, because it's a big vehicle, well for the last 20 years I have been driveing fullsize custom vans and I did not have any problems with them! Any thoughts would help!!

Answer
Hey Jeff

 One of the things that get easily overlooked is the vacuum brake booster.  With the vehicle off pump up the pedal till its nice and hard.  The pedal should be at the top and good and firm.  Start the vehicle with your foot on the brake and the pedal should drop about an inch and feel a bit more mushy.  If you feel no difference from static to running you may have a problem with the power brake booster.  With the engine running you can pull out the main vacuum line to it and make sure you have good vacuum to it.  Sometimes the inline filter gets contaminated or plugged.
 Another thing you can do is purchase an inexpensive laser thermometer.  They used to be 200-300 bucks but I have seen them for less than 20 now.  Take the vehicle out for a drive, pull over and point the laser thermometer at the rotors and write down the temps.  The front and rear should be even across and your fronts should be about 25-40 percent warmer than the rears.  The co-efficient of weight and friction will always make the front brakes warmer if they are working properly.  IF you have one wheel that is unusually hot or cold it may have a siezed slider or caliper piston.
  Another common problem that get overlooked is severe pitting on the insides of any of the rotors.  pitting decreases surface area and lowers the friction rate.  
  If you have a brake that is overheating once that brake meets a certain temp threshold it looses friction completely.  The laser thermometer is the easiest way to check brake balance and system performance.



Wayne Howie