'02 Sequoia Back Brakes heating up

[BarefootDragonslayer]

Hello everyone.
I have recently bought an '02 Sequoia SR5 4x4, and in going through the maintenance that it was due for, I replaced all four corners pads and rotors. I made sure the the calipers were not sticky, and that they slide well on the pins.
A few days later, after driving for about 25 minutes and stopping for gas, I noticed that the rear brakes smelled hot, and the rotors were bluing slightly.
The previous owner had put new rear pads and rotors on in march, and by the time I got it last month, they were so warped it would shake your teeth out when you touch the brakes.

The diagnostics I have done so far are as follows: I drove till it got hot, jacked the car up and spun the rear wheels. They spun freely, and did not feel sticky at all. I also drove it till they got hot and then cracked the bleeders loose to see if fluid spurted. It did not.
I have just replaced the master cylinder, and bled the brakes until clean fluid came out.
The rear brakes still get hot within about 10 minutes of driving, and the fronts stay cool.
Any ideas what might be causing that?

Thanks
Gunnar

 

[Twowong4words]

Odd one for sure. Its possible the piston seals are messed up and after applying the brakes the pistons are not retracting into the caliper like intended and by the time you jack it up they've finally reset themselves? Are the rear wheel bearings ok? If they were really bad and allowing the axle to deflect when weight is on the tires, its possible it could cause the rotor to be at an odd angle and be rubbing against the pads when driving but it typically would have to be pretty bad. I'm guessing there is probably a portioning valve right behind the gas tank too with a long rod that connects to the top of the rear axle. Is possible the valve is adjusted improperly or malfunctioning causing the brakes in the rear to apply more force then it should during normal braking.

 

[BarefootDragonslayer]

Odd one for sure. Its possible the piston seals are messed up and after applying the brakes the pistons are not retracting into the caliper like intended and by the time you jack it up they've finally reset themselves? Are the rear wheel bearings ok? If they were really bad and allowing the axle to deflect when weight is on the tires, its possible it could cause the rotor to be at an odd angle and be rubbing against the pads when driving but it typically would have to be pretty bad. I'm guessing there is probably a portioning valve right behind the gas tank too with a long rod that connects to the top of the rear axle. Is possible the valve is adjusted improperly or malfunctioning causing the brakes in the rear to apply more force then it should during normal braking.

The Calipers don't seem stuck at all. I used a pair of channellock pliers to reset them when I did the brake pads, and they collapsed easily. I thought maybe the rubber brake lines were holding pressure, but I replaced them and it didn't help. There is no proportioning valve on this one, I had the same thought, but on this car the ABS system manages that.
I did disable the rear brakes, and the fronts did not seem to be working correctly, so I'm thinking maybe the rears are getting hot because they are trying to compensate for weak/maybe non existent front brakes.
I have some front brake parts arriving tomorrow, and I'm hoping that that may fix my problem