Proportioning valve seems to be working in reverse.
Someone here has a similar set up probably set you straight
Someone here has a similar set up probably set you straight
Hot brakes 2 years after disc conversion
First time posting but been on this forum many times and gotten answers most times. I converted my 06 1500 from drum to disc about 2 years ago using [email protected] write up only I used parts from an 05 suburban. Truck stops on a dime and things have been perfect until just a couple months ago.
The rear brakes are grabbing more than the front which I have verified with a laser temp gun. Fronts are around 130-150 and rears are around 250-300 under normal stopping conditions. You can feel the rear brakes grab before the fronts.
Truck has braided flex hoses all the way around, brand new rotors, calipers and pads in the rear that were just replaced due to this problem but didn't fix anything. I also just added an adjustable proportioning valve from wilwood on the supply line from master to abs as I never had a valve before and truck doesn't have one from the factory. The prop valve is adjusted to max for less brake to the rear and that hasn't changed anything either.
Truck is lifted on 37s and has 214k on it. Is it possible the master is leaking internally and applying more fluid to the rear? I'm at a loss on what else to do. Also apologies for the long post, just wanted to give as much info as possible. Thanks
The rear brakes are grabbing more than the front which I have verified with a laser temp gun. Fronts are around 130-150 and rears are around 250-300 under normal stopping conditions. You can feel the rear brakes grab before the fronts.
Truck has braided flex hoses all the way around, brand new rotors, calipers and pads in the rear that were just replaced due to this problem but didn't fix anything. I also just added an adjustable proportioning valve from wilwood on the supply line from master to abs as I never had a valve before and truck doesn't have one from the factory. The prop valve is adjusted to max for less brake to the rear and that hasn't changed anything either.
Truck is lifted on 37s and has 214k on it. Is it possible the master is leaking internally and applying more fluid to the rear? I'm at a loss on what else to do. Also apologies for the long post, just wanted to give as much info as possible. Thanks
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I put the proportioning valve in after the problem started and it didn't change anything. Hopefully someone can help get this figured outProportioning valve seems to be working in reverse.
Someone here has a similar set up probably set you straight
Did you install the Disc/Disc master cylinder or do you still have your stock Disc/drum one?
Had the same issue on 2008 about 1.5 years after drum to drisc. Started driving like a car, rears were smoking a few times when I got home. More than drivable, but ass end would slide pretty hard on braking sometimes.
brake petal ended up going to floor on day. Tried just a Tahoe disc/disc master, no change. Guess disc/disc combo pressure on factory drum/disc master blew the booster. Idk but it was booster.
Put a 02 hydro boost and disc/disc master off an 2009. Petal was restored, and rear brakes were no longer over powered, but still too warm. Swaped both rear calipers for advanced store brand and everything is A1.
brake petal ended up going to floor on day. Tried just a Tahoe disc/disc master, no change. Guess disc/disc combo pressure on factory drum/disc master blew the booster. Idk but it was booster.
Put a 02 hydro boost and disc/disc master off an 2009. Petal was restored, and rear brakes were no longer over powered, but still too warm. Swaped both rear calipers for advanced store brand and everything is A1.
Still have disc/drum masterDid you install the Disc/Disc master cylinder or do you still have your stock Disc/drum one?
Update, I've replaced the master and booster with brand new units for a 4 wheel disc truck and installed a brand new OE proportioning valve. Rear brakes are still around 100 degrees hotter with IR temp gun. Only thing left is the abs assembly, could that be causing any issues like this?
The abs controller slso contains the proportioning valve between the front and rear brakes, that could potentially activate the rear brakes more than the front (but I would think it should do the fronts more than the rear).
It could also be something like the jounce hose between the frame and rear axle, if it's failed internally, it could be holding the brakes on.
It could also be something like the jounce hose between the frame and rear axle, if it's failed internally, it could be holding the brakes on.
where do you get this info?The abs controller slso contains the proportioning valve between the front and rear brakes, that could potentially activate the rear brakes more than the front (but I would think it should do the fronts more than the rear).
It could also be something like the jounce hose between the frame and rear axle, if it's failed internally, it could be holding the brakes on.
There's nowhere else for the proportioning valve to be. The MC has 2 lines out, the ABS controller has 2 lines in, and 3 lines out. I can't see GM dedicating one line from the MC for the front and the other for the rear, so you can lose both front brakes when that line fails.
The full service manual for both my '04 and '12 3500 says that pressure balance control is achieved through dynamic rear proportioning (DRP), which is a function of the ABS modulator.
The full service manual for both my '04 and '12 3500 says that pressure balance control is achieved through dynamic rear proportioning (DRP), which is a function of the ABS modulator.
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