Brake grab

[WolfPack]

Hi
  i have a 1994 Chevy G-20 van with a 5.7 the front brakes when applied pull to the left hard thin it brake evenly with a little shimmy i have check all front end parts plus the steering and the wheel Bering's the front brakes are about 1/2 used i have check the bolts that hold the caliper on. :confused:

[wavery]

Hi
  i have a 1994 Chevy G-20 van with a 5.7 the front brakes when applied pull to the left hard thin it brake evenly with a little shimmy i have check all front end parts plus the steering and the wheel Bering's the front brakes are about 1/2 used i have check the bolts that hold the caliper on. :confused:

Sounds like the pistons may be sticking in your right caliper. That will cause the left caliper to push the brake pads against the rotor 1st, then the right side may un-stick and work properly until the next time they are applied.

Sometimes when the calipers get worn, the piston(s) will seat cockeyed in the bore and stick that way until enough pressure is exerted to break the piston loose. If the other side is working properly, that brake pad will make solid contact with the rotor before the pressure gets high enough to break the faulty side loose so that it can do it's job. That will result in the good side acting like it is "Grabbing".

[Crowbar4]

Have your alignment checked, bad alignment can cause the exact symptoms you described.  The shimmy probly means your rotors need to be turned.

[WolfPack]

Thanks i am going to also look at the brake lines to when i put the pads on i had the rotors turned though pad were put on late fall 07 i am wondering if 94 g-20 had a problem with the rotors

[wavery]

Thanks i am going to also look at the brake lines to when i put the pads on i had the rotors turned though pad were put on late fall 07 i am wondering if 94 g-20 had a problem with the rotors

I'm not aware of any rotor issues on Chevy truck chassis. The G20 has pretty beefy rotors.

I can't imagine a scenario where a rotor would cause what you describe. A bad rotor will normally cause a vibration, or jerky feeling, not usually a "Grabbing". Grabbing is caused by one side pads contacting the rotor before the other. You could have a problem with the proportioning valve too.

BTW, I believe that GM recommends not turning rotors. I believe they recommend, if they are lightly scored, just leave them and let the pads wear accordingly. If they have discoloration (burned spots) or scored to under size, replace them. Double check the service manual on that but that was the recommendation when I was a Chevy Service Manager.

[WolfPack]

Well put new cailpers on and new brake lines it took all of it out smooth braking there is a little shimmy withch i think the tires need to be rebalance the pull to right is also gone.:-()

[JohnandLeann]

If you have a shimmy only when you brake, then that is most likely caused by your brake rotors being out of round and they need to be checked to see if they can be "turned" or need replacing.
If it shimmies at road speed, then I would agree with having tires checked for balance.

[WolfPack]

I will work on it after i get back from VA i drove it to work today the brakes did ok so i will put new pads and turn the front rotors aftr i get back from VA.

[bartletts]

Check the opposite side rear brake as well. I had the exact same problem on a Jeep and it ended up being that one of the rear brakes was grabbing unevenly. It surprised the heck out of me. Drum brakes are more likely to have adjustment and grabbing problems than disc brakes.

Also check to make sure the rest of your suspension is in good shape. Braking changes the forces on the suspension, and if any ball joints or bushings have play in them it can translate into a steering pull. Also make sure your tire pressure is even all the way around.