The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 1968 C10 CST DRUM/DRUM Proportioning Valve Problem

choctawchevyclassics · 07-24-2019, 09:13 PM

Just purchased a 68 C10. Driving home from work today the rear brakes started locking up and not disengaging. It has DRUM/DRUM set up with power brakes and a proportioning valve. It sounds like the proportioning valve is bad to me. I can't find one online for DRUM/DRUM. Can anybody point me in the right direction?

The rear brakes disintegrated and were locked in the braking position until I released the bleeder screw on the wheel cylinders.

I checked the wheel cylinders and they both move in and out freely, making me think proportioning valve. Any words of wisdom?

I am also going back together with all new brake parts, but can't find the valve anywhere for DRUM/DRUM.

Attached picture shows the assembly in question.

07-24-2019, 09:13 PM	#1
choctawchevyclassics Registered User Join Date: Feb 2009 Location: Choctaw, Ok Posts: 184	1968 C10 CST DRUM/DRUM Proportioning Valve Problem Just purchased a 68 C10. Driving home from work today the rear brakes started locking up and not disengaging. It has DRUM/DRUM set up with power brakes and a proportioning valve. It sounds like the proportioning valve is bad to me. I can't find one online for DRUM/DRUM. Can anybody point me in the right direction? The rear brakes disintegrated and were locked in the braking position until I released the bleeder screw on the wheel cylinders. I checked the wheel cylinders and they both move in and out freely, making me think proportioning valve. Any words of wisdom? I am also going back together with all new brake parts, but can't find the valve anywhere for DRUM/DRUM. Attached picture shows the assembly in question. Attached Images __________________ choctawchevyclassics Last edited by choctawchevyclassics; 07-24-2019 at 10:06 PM. Reason: picture