locking brakes

brokenblazer
Posts: 2
Joined: Sat Oct 11, 2014 9:02 am

locking brakes

Unread post by brokenblazer » Sat Oct 11, 2014 9:08 am

Ive a 2001 blazer, and the brakes lock up while driving, all calipers/pads are new, as is the abs controler, brakelines, master cylinder. what can the problem be??? After the car sits for a while all work fine, but after a few miles you can feel the pedal get hard and the car stops by itsself.

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carriedi
Posts: 2573
Joined: Wed Apr 10, 2013 12:42 pm

Re: locking brakes

Unread post by carriedi » Sat Oct 11, 2014 11:23 am

this is going to need to be checked out where you can get the tires off the ground when it is locking up. once the brakes start to lock up you need to find out which wheels are locked. is it all the wheels? is it just the front? is it just one wheel. that will tell you what you need to look for.

when you find the wheel that locks up (any wheel that is locked up) release the bleeder screw and see if there is a build up of brake fluid pressure in that wheel. If brake fluid shoots out under pressure tighten the bleeder screw back up and see if the wheel is freed up now. If only the one wheel was locked up you might have a bad brake hose. If both wheels (like both front were locked up) are now free wheeling then you're going to need to check the ABS unit, the combination valve and the master cylinder. Drive the vehicle until the brakes start to lock up again and then release the brake line at the master for the wheels that are locked up. then at the combination valve, then at the abs unit to see which place there is the pressure build up holding the brakes.

you could have a problem with your booster, the master, the combination valve, the abs unit, the brake hoses or individual brake units, calipers or wheel cylinders. you're going to have to pinpoint the problem and follow it back from there
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brokenblazer
Posts: 2
Joined: Sat Oct 11, 2014 9:02 am

Re: locking brakes

Unread post by brokenblazer » Sat Oct 11, 2014 1:22 pm

thanks for the info , nice to have a format to follow

raneger
Posts: 22
Joined: Sun Mar 01, 2015 12:47 am

Re: locking brakes

Unread post by raneger » Tue Mar 10, 2015 6:32 am

Air bubbles, leaky seals, and oil on the brakes would cause no braking, and i doubt there is something in the pads, a bad caliper could be it.