Brake rotor rust - indicative of caliper issue?

Originally Posted by fsdork
Attached is a photo of one of the rear rotors on my '03 Explorer. All four rotors look similar, although the rust is a bit more scaly on the rear. All four corners need new pads, and based on the amount of rust on the rotors, I plan to replace them as well.

What I'm looking for input on is the ring of rust around the outer edge of the pad contact surface on the face of the rotors. I realize a small lip of rust in that area is normal, but this seems to be a bit much, and definitely overlaps the pads in that area, so it seems there should be pad contact there by design. Is this caused by the caliper pins not functioning correctly? If so, it is likely that servicing the pins when I do the rest of the work will cause the calipers to function properly again?

I'm trying to put together a Rock Auto order, and would like to order the calipers along with everything else if it is reasonably certain I will need them. If the pins need to be inspected to determine whether they can be brought back to life, I could order the pads and rotors from Rock Auto, then get calipers locally if they are found to be needed during disassembly.

Any input is appreciated!


The pads are stuck on their sliders due to rust, as you can see the rust is forming in the slider area. The pads cant on the unsupported side and brake there only. The rotors need replacing or resurfacing, you can never get rid of that rust anymore just by having the pads work correctly.

Any rust under the friction material is an abnormal condition and points to something sticking.. pads, slider pins or caliper piston but in this case pads.

Slider pins act on the whole pad and usually makes one pad wear faster than the other. but neither has a significant impact on brake power, but you can get overheating issues.

Pistons influence brake power and balance.
 
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Adding to the stainless steel slider comments...you may already know, but sometimes it's not enough to just wire brush underneath the stainless steel slider clips. Sometimes you have to file that area to remove the rusty enlarged metal because it "mushrooms" the slider clips to cause binding (I forgot the term for this). And, it's consensus to grease in between the stainless clips and caliper to slow this corrosion point. Maybe preaching to the choir, LOL.
 
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