Rear brake levelers on 84 C20?

[Gregor]

I have a heavy duty 84 C20 with the rear brake leveler . I would like to eliminate this feature as this truck will be a daily driver and other than an occasional trip to lowe's I really don't haul anything in it that a half ton would easily take care of. Could I just take it out or is the proportioning valve specific for this setup? I don't even see these levelers available anymore. Any insight on this would be warmly welcomed.

[VileZambonie]

This is called a height sensing proportioning valve. The proportioning valve is used to help prevent rear wheel lock up. If yours is still functioning then keep it. If it's not you can bypass it just get used to how your brakes work without it especially when you have different pay loads in the truck.

[Gregor]

I'm on the same page with you. Just trying to track down some weird brake problems, might not even be the brakes. Something is locked up every once in awhile after doing some driving... parking and comming back out to truck to drive away and truck wont move, then all of the sudden it breaks free. Hoses aren't sucked close, no wheel cylinders are leaking( the GMC would lock up a rear brake comming to a stop because of a leaking rear brake cylinder but never was locked from a stand still to drive). I rescued this truck from the mountains where the previous owner abused the poor thing. Back to topic though... so the main proportioning valve would not be any different than on a truck without the HSPV, correct.

[frogman68]

What about the E-Brake cable? That could be sticking ..

[VileZambonie]

If you have a 2 stage combination valve it only has a metering valve and differential pressure switch. The height sensing proportioning valve is seperate. To do it right you would want to replace the combination valve with a 3 stage combination valve and bypass the height sensing proportioning valve. If you just bypass it, it will work but your rear brake pressure will have no pressure limit (typically 600psi) and your rear brakes will lock up very easily.

As far as your sticking issue I would go through the brakes very thoroughly (check park brake sticking like frog said) and go from there. Make sure the shoes are sitting on the anchor pin and the shoes are installed correctly (primary on the front)

[Gregor]

Thanks to both of you gentlemen. I will check park brake like frogman 68 suggested and start going through brakes on my day off Friday. Excellent info on the proportioning valve. All this will get me on the right track. I'll post again with what I come across when I start checking at the end of the week.

[Mr Diesel]

I have seen the flexible rubber hoses on the front deteriorate internally to the point that they cause brakes to stick. Might look fine on the outside but inside are falling apart and clogging.

[Gregor]

Thanks Mr Diesel, I got all new flexible hoses front and rear just in case

[gold84gmc]

I have seen the flexible rubber hoses on the front deteriorate internally to the point that they cause brakes to stick. Might look fine on the outside but inside are falling apart and clogging.

i would say thats your problem....there is a flap or rubber in the hose thats not allowing the fluid to go back so it keeps the pads and shoes against the rotors and drums

[Gregor]

Been super busy and have not had time yet. Those old ones will definitely get trashed though! Thanks