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boxrodz · 11-17-2006, 06:13 PM

Yeah, I figured GM combine the metering valve starting in the early 70s.

The metering valve is used to delay the application of brake pressure to the front brakes until the some brake pressure rear brakes have been established during a braking operation. Otherwise, the fronts would brake first. Depressing the metering valve allows you to bleed the front disc without having to build-up the pressure in the rears. I used a block of wood to depress the metering pin inward. (Worked for me.) Be careful no to rupture the rubber boot covering the metering pin.

I wouldn't think that the combination valve is defective. I'm thinking that you still have air in the system. The valve shouldn't cause you problems while bleeding the brake system. BTW, is you brake warning light on the dash come on when your truck is running? (What problems were you having with the brake system before you replace the mc and the booster?)

11-17-2006, 06:13 PM	#6
boxrodz Until Seventy Times Seven Join Date: Feb 2005 Location: Rocky Mountain Front Range Posts: 1,301	Re: 1974 C20 Brake problem Yeah, I figured GM combine the metering valve starting in the early 70s. The metering valve is used to delay the application of brake pressure to the front brakes until the some brake pressure rear brakes have been established during a braking operation. Otherwise, the fronts would brake first. Depressing the metering valve allows you to bleed the front disc without having to build-up the pressure in the rears. I used a block of wood to depress the metering pin inward. (Worked for me.) Be careful no to rupture the rubber boot covering the metering pin. I wouldn't think that the combination valve is defective. I'm thinking that you still have air in the system. The valve shouldn't cause you problems while bleeding the brake system. BTW, is you brake warning light on the dash come on when your truck is running? (What problems were you having with the brake system before you replace the mc and the booster?) __________________ boxRODz 1983 C10 SWB Fleetside When two halves is gone, there's nuthin left. Two nothings is nuthin. That's mathematics son. You can argue with me but you can't argue with figures. Two half nothings is a whole nuthin... Last edited by boxrodz; 11-17-2006 at 06:18 PM.