Locking front brakes

[Dakerstrom]

The front brakes on my 92 Yukon intermittently will not release. Replaced rotors and pads and had to crack open the brake line (bleed fluid) to retract the piston. Removing fuse on ABS has no effect.

[tempfixit]

Is it one side or both sides. Sounds like the brake line hose has collasped internally not allowing the piston to release.

Hope this helps

[Dakerstrom]

[quote=tempfixit]Is it one side or both sides. Sounds like the brake line hose has collasped internally not allowing the piston to release.

Hope this helps[/quote

It's both sides. I'm able to release the pressure also by cracking the front fittings on]the ABS unit. It is definitely intermittent. I tried using a C clamp to retract the pistons (both) when replacing the pads and was only able to retract it after cracking the fitting on the caliper.

Dave

[tempfixit]

You may need to have the ABS unit scanned with a capable scanner. When you replaced pads were the pads worn evenly on both sides?

[Dakerstrom]

[quote=tempfixit]You may need to have the ABS unit scanned with a capable scanner. When you replaced pads were the pads worn evenly on both sides?[/quote


Thank you. Ya, pretty much. They had locked up when my granddaughter was driving it and wore the pads down to metal and warped the rotors. What is a capable scanner? If the problem is the ABS unit, I'd like to try and bypass it and run directly from the master cylinder. My only concern is the drums on the rear and the disks on the front. Probably will need a proportioning valve. I live in Florida and keep the car in Massachusetts to use when I'm there - I just got back and won't go north again till June.]

Dave

[maxwedge]

This can also occur if the brake fluid was accidently contaminated with say p/s fluid, common error with amatuers, see if the fluid looks oily or is seperated.

[Dakerstrom]

Thank you. The brake fluid is nothing to be proud of - kind of rusty looking. I'll flush it out with new fluid when I go back north in June.

Dave

[maxwedge]

If it is contaminated this causes the cups in the M/C to swell blocking the by pass port and applying the brakes.