Barberryn

1996 v6 xle
Had been working well for last year dispite having "trac off" light on sence buying car used.
Other day car front calipers would not release after normal braking. I had to nurse car home in short runs as rotors would really heat up (blued them by the time I got home).
Calipers well lubed and slider pins free. Caliper pistons not siezed and can be pushed back in with c-clamp, although with effort. Did this several times in fact. Unhooked connectors to ABS unit and pumped up brakes with engine idleing and they still "lock on". Even after leaving car overnight, the front wheels cannot be turned by hand while the rears release imediately.
Could proportioning valve be stuck or will abs unit lock the fluid in the front calipers. Hard to imagine that both front hoses failed internally (at the same time on the same trip) and are "check valving" .
Any advice at this point will help. I have the car up on 4 axel stands and need it running!

jdmccright

Very similar to another recent post. I would check either the brake master cylinder or the combination valve. Crack open the brake bleeder screw on one of the calipers and see if fluid shoots out (be ready to catch the mess). After this see if the wheels are easier to move. If so, the master cylinder piston may not be retracting fully allowing the system pressure to be bled off or the combo valve is sticking. Good luck!

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Current Garage:
2003 Pontiac Vibe 1.8L AWD
2003 GMC Envoy XL (aka "fat-a$$") - K&N air filter, otherwise stock.
1995 Chevrolet C2500 2wd, 5.7L - K&N air filter, otherwise stock...my weekend hauler.
1992 Toyota Camry LE 2.2L - K&N air filter.

Vehicle History:
2004 4.7L Dakota Quad Cab 4x4
1996 GMC Jimmy 4wd
1992 Chevrolet S10 Ext. Cab 4.3L
1995 Honda ST1100...my first (and only) new vehicle.
1980 Yamaha XS400
1980 Mercury Bobcat...my first car.