Brakes Problems

[RIDDELER]

1989 GMC 2500 (V8) 160,000 miles

 

Truck: Rear wheel brakes lock-up with slightest touch of pedal (intermittent).

 

I've replaced brake line, rear-wheel cylinders, bled entire system with fresh brake fluid. My rear wheels ocasionally lock-up with the slightest touch of the brake pedal.

 

I tried unplugging the ABS at one time to see if that would correct the locking-up problem. They still lock-up intermittently.

 

Thank you for any information you can supply.

[RayGMC]

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Make, Model, Year, Miles?

[RIDDELER]

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1989 GMC (2500) V8 160,000 miles

[Nytemare]

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Make, Model, Year, Miles?

 

 

1989 GMC (2500) V8 160,000 miles

 

You have a proportioning valve problem from the sounds of things.