What's causing build-up on my brake rotors?

[D189379]

On both of my front rotors, there is a build-up of material on the inside only of each rotor (both sides facing the engine). The material is quite bumpy and I have no idea what it might be. There is a thin band of shiny metal showing from the small contact patch where the inner brake pads are still touching.

The outside faces of both rotors are completely fine, still shiny and smooth.

Both inner and outer pads look good so I'm at a loss to understand what might be happening. I checked the caliper and both inner and outer pads are sliding freely. The brakes still work fine and there is no vibration or anything when braking.

The truck is a 2008 Nissan frontier with a 6spd manual. I'm super easy on the brakes as I have 60,000 miles on the pads and they still have 75% life left. I'd be surprised if I've made more than 3 or 4 panic stops in those 60,000 miles.

Obviously I need to replace the rotors and pads, but I'm wondering if this issue might be resolved by switching to a slotted rotor? (I'm guessing maybe I'm too easy on the brakes and snow/ice/salt/road debris is getting trapped against the rotor? Maybe the slots will help displace the debris? I have no clue lol!)

Any thoughts/tips/suggestions on what might be going on?

 

[D189379]

Heres a photo of what it looks like. This isn't my truck, but it looks like this.

http://www.subaruforester.org/vbulletin/...cs-015-copy.jpg

 

[SwampSurvivor]

There's a few things that could have happened:
1) The sliders are hung up so the outside pad is able to provide more force
2) The inside pad is very worn and only making contact in that one narrow spot
3) The rotor was rusted like that before you put the pads in (could have been from either above) and the rust just ground down the new pads.

Most likely, it's because you are too easy on the brakes. My dad has to replace the rear brakes every other year on his F350 because he just doesn't drive it hard enough and the rear brakes do exactly that all the time.

If you don't stop hard enough to heat up the brakes and "burn" the rust off of the rotor, it's going to build up enough rust that you will have to get the rotors resurfaced / turned in order to get rid of it.

 

[supton]

I get that a lot it seems. Takes a few years though, and I'm going to see if regular dissassembly and lubing of the pads (so that they will slide) will help. I also get hammered by parking close to a road; my rotors are always getting a sheen of rust after every rain.

 

[Donald]

Wouldn't regular use (every day or three) get rid of the rust even with normal braking?

 

[KrisZ]

Originally Posted By: Donald
Wouldn't regular use (every day or three) get rid of the rust even with normal braking?


Not if you're constantly easy on the brakes. Basically, if during your drive the brakes cannot remove all the surface rust because of gentle application, that spot remains rusty and more rust starts to build around it. Over time these spots will get bigger and bigger resuting in just a small patch of the rotor actually contacting the brake pads.
I think that the reason why it happens on the inside surface and not the outside is that the inside surface is actuated by the piston and it retracts quite a bit when brakes are not used. The outside surface, on the other hand, is just dragged along by the squeezing motion of the piston, so naturally it doesn't retract as far as the piston and always draggs the rotor surface even if brakes are not applied.

My 03 Focus, with what seems to be the original rotors is like that. The outside is fairly clean but the inside of the rotors is badly rusted. So despite plenty of "meat" left on the pads it needs a brake job.

 

[Cardenio327]

Originally Posted By: D189379
I'd be surprised if I've made more than 3 or 4 panic stops in those 60,000 miles.


^^This.^^

Try a controlled high speed brake check in a safe area without traffic about once every 500 miles.

 

[GSCJR]

There's no such thing as, too easy on the brakes. As Miller88 has suggested, the in-board pads are not moving as designed within their channels. Remove, clean the pads and clean the affected areas. Lubricate with an approved brake lube and replace the rotors. Good luck!

NB. Fellow canadian, this is also due to the elements.

 

[Vikas]

I wish I knew about this. I am one of those guys who is extremely easy on the brakes and now reading this I understand that it might not be the best thing.

 

[A_Harman]

Nix on the slotted rotors.
They make noise and wear out pads very quickly.
I've tried various combinations of drilled and slotted rotors on my track cars over the years, and always go back to smooth.

 

[901Memphis]

Try to take some of the material off with a couple of controlled panic stops if you can find a road suitable to do so. I think a couple of 70+-5 mph stops without stopping in between will take most everything off and then let them cool before stopping while hot.