Discoloration (glazing?) on Brake Rotor

[RDOOGZ89]

Ive been smelling a strong burning smell from the rear driver side wheel well area after highway driving.

I've noticed there is a discoloration (blotchey spot) on the rotor and the pads are low but not "dead". The spot and smell is from the pads overheating right?

I read some on some old posts that the floating calipers in the rear can get sticky if the pins are old and not lubed well. Any thoughts on this?

I am hoping a pad and hardware change will help. I have no symptoms of a frozen caliper (that I am aware of): excessive vibrations while driving, shuddering while braking, etc.

Any serious thoughts/opinions are appreciated. I'm sure new rotors and calipers are in my future, but that is just not an option at the moment. (Two kids and Christmas coming is making my wallet cry.)

 

[Bumbo]

Any chance the parking brake star might be adjusted incorrectly?

I had a froze caliper in the front and the symptoms were a pull to one side during heavy breaking and uneven wear of the pads. Basically looked like only one piston was pushing on the pad.

I would remove and replace the pads, at least get some eyes on it.

Alternately you can get a cheap IR / non-contact thermometer and look at and compare rotor temps. Seems like a good way to see if there is any unwanted contact /friction after a few blocks of driving.

 

[RDOOGZ89]

Any chance the parking brake star might be adjusted incorrectly?

I had a froze caliper in the front and the symptoms were a pull to one side during heavy breaking and uneven wear of the pads. Basically looked like only one piston was pushing on the pad.

I would remove and replace the pads, at least get some eyes on it.

Alternately you can get a cheap IR / non-contact thermometer and look at and compare rotor temps. Seems like a good way to see if there is any unwanted contact /friction after a few blocks of driving.

I'll hit it with the IR when i get home, I have one but always forget about it.

When you say that only one piston was pushing on the pad I'm assuming one of your front calipers froze up? I had that happen to me and I did not get the pulling to one side but I would get this violent shuddering/ vibration when coming to a stop or tapping the brake at highway speeds. It sucked, I wound up replacing calipers and rotors on both sides to avoid a repeat.

The E-brake has not been adjusted since i've owned the truck because I have not had any problems with it holding.

You are right though, I need to get the wheel off and get some eyes on it.

 

[RDOOGZ89]

This is a picture of the discoloration i was talking about. Is this glazing?

Hit the rotor with the IR gun when i got home. It is 15-20 degrees hotter than the others. Damn!!!

 

[AuSeeker]

In your photo the whole rotor surface looks like it's been overheated to me, it appears to have a blue/black coloration to it,
if it does then the rotor needs to be replaced, I suspect you have a sticking caliper there, if it's just the pad to caliper
contact/sliding area and or pins causing it to stick then replacing the pads and lubing with the proper silicone brake grease should
save you from having the also replace the caliper as well, it's more important to lube the area where the pads contact/slide on
the rotor than it is to lube the pins since the pins fit loosely on the pads, but a little coating on the pins is not a bad idea to help
keep down on corrsion on the pins.

Hard to say what the "spot" is.

 

[RDOOGZ89]

In your photo the whole rotor surface looks like it's been overheated to me, it appears to have a blue/black coloration to it,
if it does then the rotor needs to be replaced, I suspect you have a sticking caliper there, if it's just the pad to caliper
contact/sliding area and or pins causing it to stick then replacing the pads and lubing with the proper silicone brake grease should
save you from having the also replace the caliper as well, it's more important to lube the area where the pads contact/slide on
the rotor than it is to lube the pins since the pins fit loosely on the pads, but a little coating on the pins is not a bad idea to help
keep down on corrsion on the pins.

Hard to say what the "spot" is.

Thanks, pads and hardware are going to be replaced tomorrow morning. Hopefully, the rotor can wait till after christmas. I notice that discoloration now that you point it out. Im still new to wrenching, so i appreciate the lesson. Thanks again.

 

[Bumbo]

Thanks, pads and hardware are going to be replaced tomorrow morning. Hopefully, the rotor can wait till after christmas. I notice that discoloration now that you point it out. Im still new to wrenching, so i appreciate the lesson. Thanks again.

I would do it all at once... the caliper and pads are going to have to come off again when you do the rotor anyways.

Adding rotors wont cost that much... RockAuto / Centric Premium rotor is like $40, or less each if you were so inclined.

I would not want to do the labor twice for that type of money.... plus, my OCD would kick it preventing me from throwing on new pads on a rotor that needs replacement.

Again, I would be more interested in identifying the cause, vs throwing parts at it. If this is a caliper issue, you are going to be back to square one in no time.

 

[325runner]

most likely will need the caliper, try compressing the piston in and see if it is hard to push in, if so replace it

 

[RDOOGZ89]

I would do it all at once... the caliper and pads are going to have to come off again when you do the rotor anyways.

Adding rotors wont cost that much... RockAuto / Centric Premium rotor is like $40, or less each if you were so inclined.

I would not want to do the labor twice for that type of money.... plus, my OCD would kick it preventing me from throwing on new pads on a rotor that needs replacement.

Again, I would be more interested in identifying the cause, vs throwing parts at it. If this is a caliper issue, you are going to be back to square one in no time.

most likely will need the caliper, try compressing the piston in and see if it is hard to push in, if so replace it

I am going to have to agree with you there, going to swing by napa after work see if they have any rotors in stock.

I remember when my front caliper seized that it was near impossible to compress the piston. I know what to look for in that regard. I thought that the floating calipers in the rear were less prone to seizing.

I will post an update tonight after I get the wheel off. I really hope it is something simple like the pins are getting stuck from rust.

 

[waypoint]

Get a tube of Silglyde brake grease while you're at NAPA. It's great stuff for the slider pins on the rear 2-piece brake assemblies...remove the pins, clean and apply Silglyde, they won't ever seize. Also get regular brake grease for the piston contact surface and caliper contact surfaces to ensure the pads don't squeak. Get these areas clean first.

 

[RDOOGZ89]

Update on this...

The shop that installed my new tires over torqued my lug nuts. I broke two wheel lock keys trying to get the wheel lock off just one of the tires. Had to give up and drop it off at my local shop to cut the damn things off.

 

[Bumbo]

I hate running into problems like that.