Front Brakes Dragging
Registered User
Joined: May 2015
Posts: 8
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From: Salina KS
Just checked the pedal. It's good. This is getting very old. been going on almost a year. Almost time to replace the front pads again. This is hard on my mileage too. If I stay on this it will be resolved. How hard can this be, it's just brakes!!!
Grand Champion
Joined: Feb 2015
Posts: 7,435
Likes: 578
Do the calipers move freely on the bracket?
X2! The sliders need to be greased periodically to keep them from sticking. Was this done when the parts where replaced?
Registered User
Joined: May 2015
Posts: 8
Likes: 0
From: Salina KS
I've had the truck on jack stands and have created the condition where the pressure does not release. The pressure is held by the combination/proportioning valve, breaking the connection between the proportioning valve and the master cylinder produces a small slow leak, breaking the connection below the proportioning valve produces a tablespoon sized squirt. The proportioning valve indicator pin protrudes about half its travel when the condition happens. The indicator pin has to be held forward by the rear piston of the proportioning valve which is forced forward by the rear brake fluid. While the front piston is held forward the front brake fluid can return to the master cylinder through the built in check valve of the forward piston.
The proportioning valve is no longer manufactured. I've purchased a salvage proportioning valve, but after disassembly it looked to be in worse condition than mine. I reassembled the original valve block using the pistons from the salvage valve with no change in symptoms. Today I'm replacing the valve body with the salvage pistons.
Wish me luck.
Administrator
Joined: Apr 2010
Posts: 87,403
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From: Clayton MI
(don't recall if I have asked this in this thread.....) How does the pedal feel? Do you get good firm pedal right away? Excessive travel before something happens? Brake lite coming on at all?
Wonder if there isn't still some air in the front lines giving you fits.
Wonder if there isn't still some air in the front lines giving you fits.
Grand Champion
Joined: Feb 2015
Posts: 7,435
Likes: 578
The indicator pin has to be held forward by the rear piston of the proportioning valve which is forced forward by the rear brake fluid.
I've replaced the vacuum booster, master cylinder, both calipers and pads, both flexible front brake lines, rear wheel cylinders and shoes and reconditioned the proportioning valve. I have NOT replace the RWAL. This problem is intermittent, when it occurs the indicator pin protrudes from the proportioning valve about 1/2 of its travel, not enough to turn on the ABS warning indicator.