Rotor discoloration, pulsing

[mxer147]

Just replaced rotors and pads because of pulsing so I thought the rotor was warped. The problem still exists and I notice the new rotor is discolored. Bad wheel bearing? Maybe caliper? I greatly appreciate your help, thank you.

2014 gmc sierra 1500.

 

[Turbo4whl]

1) Collapsed rubber brake hose? Fluid applies under master cylinder pressure, but does not release fast.

2) Piston stuck in the caliper bore? Same, applies but not fully releasing.

 

[mxer147]

I just noticed that the F shaft has significant play at the differential. I think the inner shaft is the issue. Any advice?

 

[Radiohead]

1) Collapsed rubber brake hose? Fluid applies under master cylinder pressure, but does not release fast.

2) Piston stuck in the caliper bore? Same, applies but not fully releasing.

Or simply a stuck caliper. But the hose thing is easy enough to diagnose.

 

[Turbo4whl]

I just noticed that the F shaft has significant play at the differential. I think the inner shaft is the issue. Any advice?

No. the hub and rotor bearings rotate on the spindle. The only time and axle shaft would effect the spindle is if it breaks and is banging on the inside of the spindle. If it is loose because of it's worn bearings, it still has no effect on the spindle.

 

[Turbo4whl]

The items to check have been stated. Caliper needs to move freely. Piston can't be stuck. And the most common failure for your condition is a rubber brake hose.

What happens to the hose, the inner bladder of the hose detaches from the outer casing. The master cylinder with lots of pressure pushes the brake fluid through the failed inner bladder. When released, the bladder acts as a check valve and holds some pressure on the piston. This makes the brake pads drag, heating and warping the rotor.

The brake hose can look fine from the outside.

Drive the truck, use the brakes and get them warm. Drive back and jack up the wheel and see if it spins free.

 

[HotWheelsBurban]

The items to check have been stated. Caliper needs to move freely. Piston can't be stuck. And the most common failure for your condition is a rubber brake hose.

What happens to the hose, the inner bladder of the hose detaches from the outer casing. The master cylinder with lots of pressure pushes the brake fluid through the failed inner bladder. When released, the bladder acts as a check valve and holds some pressure on the piston. This makes the brake pads drag, heating and warping the rotor.

The brake hose can look fine from the outside.

Drive the truck, use the brakes and get them warm. Drive back and jack up the wheel and see if it spins free.

And when you get it apart, clean and lube all the caliper pins with hi temp brake grease. The stuff I use looks and feels kinda like butterscotch cake frosting, and you need to "frost" the pins and contact surfaces (where the calipers rub/slide on the spindle brackets) so that the calipers can move freely side to side on the brackets, during normal brake operation.
I'm not trying to talk down to you; just not sure of your level of expertise.....and bad brake hoses will F things up big-time, even if they don't cause a wreck. BTDT with my Burb....

 

[mxer147]

Excellent advice, thank you. I’ll let you know what I find.

 

[mxer147]

It turned out to be a warped rear rotor, the metal tab which keeps the pads off the rotor was worn off, unsure why it wore off but bottom line it’s repaired. Replaced the axle bearing, seal and changed the front differential fluid. Next, change the rear differential fluid….always something. Also, changing out the bonneville power steering pump which front bearing and seal worn and leaking. This keeping me from working on the K20. Thank you all for your awesome support, greatly appreciated.