Pulsating brakes [Archive] - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

: Pulsating brakes


ma2169
06-21-2007, 08:38 PM
ok so my brakes were pulsing pretty bad, in fact the whole trailblazer felt like it was rocking when i would apply the brakes. this would happen at all speeds fron city driving to highway driving. so i changed the front brakes and rotors and its still happening although not as bad. this is driving me nuts any ideas what to do. could it be the back brakes too?

thanks

Envoyguy05
06-21-2007, 08:41 PM
yes the rears tend warp too

gdewit79
06-21-2007, 09:06 PM
:iagree: Chances are, the brakes have been applied fairly hard at least once. I bet if you change the rear as well, the problem will disappear. :m2:

SilverUnicorn
06-22-2007, 07:40 AM
:iagree: also. Sounds like the back ones need some looking at as well. Another thing to consider is to make sure all the calipers are working properly.

On my cavalier, we replaced everything and it was still not right, and the mechanic discovered that both fromt calipers were only pulling in on one side. They were bound up and not applying pressure equally.

Chris

ieatglue
06-22-2007, 09:47 AM
Would it be possible to have the rears turned on a lathe? I'm sure that they aren't used as much as the front brakes, so they should still have some good amount of use left in them :undecided

JFSebastian
06-22-2007, 10:02 AM
Would it be possible to have the rears turned on a lathe? I'm sure that they aren't used as much as the front brakes, so they should still have some good amount of use left in them :undecided

When I had my braked done they had worn fairly evenly front and back. Nothing like my experiences with back drums. I thought I was doing them sooner than I needed in order to save the rotors, but they seem to be throw aways like my BMW, not like older GM cars I have owned where you could machine the rotors. The rotors for my BMW were actually cheaper, and good thing too because they didn't last as long.

justblazin
06-22-2007, 10:35 AM
Also check you caliper pins for free movement, I had one that was seized in place. And my truck would pull to the left while braking and make a go awful noise, like a rusty door. Replaced the pin and the rubber dust boot and now all is better.

bullethole
06-22-2007, 12:33 PM
As was mentioned, check and make sure the pins are greased and the caliper is free to slide. Also check and make sure all the lug nuts are torqued evenly to 100/110 ft. lbs. Lug nuts tightened by those monkeys at the tire places with a 500lb. air wrench can distort the rotor. Any good tire/brake shop will use torque sticks or torque wrench to install the lug nuts. If they do not, get out of there, they do not know what they are doing. :nono:

gmcman
06-22-2007, 01:29 PM
Something to keep in the back of your head...when you brake and the wheel shakes back and forth then you know the fronts are warped. When you get a back and forth motion in your rump on the seat then the rears are warped.

ShadowClutch
06-22-2007, 01:52 PM
Yeah my breaks did this too when I first got my TB in March. The rotors were warped pretty bad, but my mech took care of it. Hope that's all you gotta worry about.

hatchet669
06-22-2007, 03:44 PM
Something to keep in the back of your head...when you brake and the wheel shakes back and forth then you know the fronts are warped. When you get a back and forth motion in your rump on the seat then the rears are warped.

hey i learned somethgin new... thanks for that info lol

GUNRDY
06-23-2007, 12:18 AM
While your getting the brake work done, you might want to also get your wheels and tires balanced.

G.

Dave
06-23-2007, 11:50 AM
This seems to be an issue on the Trailvoys at least the first couple years models. My 03 TB EXT did it around 25k, they turned the rotors and it went away for a while. I later had the brake fluid changed and it went away but was returning (after 15k or so) when my Trailblazer was totaled. I'm thinking it COULD be air in the system also.

Scarsman
06-24-2007, 03:21 PM
If the rotors have enough metal on them still you may be able to have them turned true again. If not, all you can do is replace them. You might look at your rotors and see if there is an "imprint" of the shape of the brake pads. If there is then they will be no good. If you brake really hard or from high speed and then stop with the brakes on, the heat will actually transfer friction material onto the rotor. This creates a "thick" spot on the rotor causing pulsing. It also changes the metalurgy in that spot of the rotor making a hard spot. Thus you can have them turned and they will be great for awhile, but that spot will not wear the same as the rest of the rotor and you will have the pulsing back again in time. So, if you ever brake hard and get them hot, try not to sit still with the brakes on before they cool down.