brake pedal still seems to low feels like only the fornt discs are working

[aidenj454]

I'm new to your forum ,hoping you guys can give me some advise.my 70 el camino has front discs, they look stock but I'm not sure and drum rears, I replaced master cylinder calipers,rotors, drums shoes,wheel cyls, spring, adjusters and rear end brake lines. I have bleed the brakes multiple times with vaccum bleeder, power bleeder, and even tried speed bleeders. The pedal still seems low, while out for test run, it seems like I only have front brakes. The rears have bled fine ,fluid flow, even gravity flow What have I missed? Only thing I haven't done is to bleed them old school way with two people. Could it be as simple as that?

[shadowgray396]

Did you adjust the brake shoes on the rear out so they just touch the brake drums?

[aidenj454]

yeah, I did them twice , brought them up to dead stop and backed off to a slight drag. I even bought two different master cylinders, one with both front and back bowls the same size and the one with the large front bowl and the small back bowl. any ideas?

[Hank70SS]

Proportioning valve?

[aidenj454]

Hank, I don't have a valve body(proportioning valve) below to the master cylinder, I do see one mounted half way down on the front frame rail, is that what I'm looking for. Are you thinking, bad valve, cutting to much pressure to the rear drums?

[shadowgray396]

In 1970, the distribution block is the same for drums or discs.That is what is down on the frame.
http://inlinetube.com/Prop%20Valves/PR-107.htm

In 70 on the Chevelle had a proportion valve (or some call it a metering valve) just below the master cylinder and a pressure hold off valve in the rear by the rear axle. Not sure what the ElCamino had.

You can replace the distribution block with a combination valve from 1971 & up model, which incorporate the metering and proportioning valve into the distribution block. Note that the fitting sizes aren't the same between the two.

[aidenj454]

Thanks Ray. So if there isn't a proportion valve and pressure is the same front and rear, it should react with rear drums engaging before front discs, causing rears to lock up in a hard stop. I think I'm going to change the distribution valve, large line in frame to the rears, flex hose to rear distribution T block (all looked to be in good shape, maybe corrosion on inside of the tubes have restricted the flow from 43 years of moisture). Only thing I haven't changed. Thanks for the help guys.

Jim.