Outer rotor is as you'd expect, all shiny and clean from pad contact.

Inner rotor surface has a narrow stripe of clean metal and then just rust on the surface.
The inner pad is not making full contact.

What do I need to replace?
Rotor?
Caliper?
Pads?

 

You need to check two things. The pad mount for grooves in it made by the pad being only in one spot too long. The fix for that is to weld and grind it smooth. The other is the rods the caliper slide on. The caliper needs to move smoothly back and forth

 

Not sure what the "pad mount" is.

Also not sure what you mean by "pad in one spot for too long"
The pad is technically working, since there is a clean ring on the rotor surface.

 

I don't think the pad was frozen in one place, b/c the rotor has clean grooves on it.
That means at least some part of the pad is moving and working
I think some junk has built up on the pads

 

Where is the clean ring? Is it at the top or bottom of the pad surface? In other words, does it look like the pad is hitting it at an angle?

Pad surface is the part on the steering knuckle where the pads slide. It is common to see grooves form in this part.
You would see problems with the pad sliding on the knuckle on the inner pad since the outer pad is fixed. Of course, this could also be a caliper problem where the piston isn't moving out of the bore or an issue where the caliper isn't sliding on the guides correctly.

Also extremely low quality pads or a warped rotor could be at play.

Pictures would be extremely helpful.

 

If there's junk on the pad surface, grab a can of brake cleaner and give it a thorough spray down.

 

If I remove any of this, I am just going to replace it with new parts.
Labor and effort are worth 1000% compared to cost of parts.

Rotors and pads are Raybestos installed in 2012 (40k miles ago)

Pads were $50 in 2012, now they are $73
Rotors were $42 in 2012, now they are $43

I am just going to replace rotors and pads.

 

That doesn't sound like a cheap set of pads. I'm not familiar with that brand but I think they're pretty reputable.

You don't want to just replace the pads and rotors without being confident that there isn't an issue with the caliper - you'll just end up ruining the new parts.

Let me see if I can dig up the picture of the ruts that were mentioned.

If you want to just replace parts to correct the issue, I'd do the calipers too. Are you doing this yourself or having a shop do the work?

 

https://www.cherokeeforum.com/attach...r-dsbefore.jpg

This pic shows the ruts that the pads can get hung up on. If yours has the ruts the best fix is to weld a little metal in and smooth it out, but if they're not deep you can sand the edges and put a good brake lube on and be ok for a bit.

 

You need to factor in the cost of a new knuckle as well, as PatHenry stated, the knuckle has pad guides, which the pads rest and slide on, over time, it becomes worn and creates a divot on the guide, which causes the caliper to stick, resulting in grooves and uneven wear. The cheap and easy solution is to fill that groove with weld, then grind smooth, restoring the guide to original configuration. Or go through a crap ton of labor and new parts and have it cost more than it needs to.

I'll find some pics and post in a few.

 

So here's what we're talking about...you see the groove worn on the pad guide, then what it looks like after it's filled and ground smooth with the rest. I did this with my knuckles removed, but have also done it on other guys rigs while still on the car. It's easy and fast, and the shop should be able to handle it easily if they're worth their salt.

 

Those little divots should not be there?
Those are formed from the "ears" of the brake pads?
How does that even happen? Car sitting for years?
I will look for these divots, but my pads are moving, since there is shiny metal on both sides of the rotor.

 

Thanks for the photos.

Why does the XJ have bizarro complications on literally every single project?

Brake jobs one step up from Jiffy Lube flunky that cost $40 with coupons.
How does only the XJ require a freaking welder and grinder to do the ****ing brakes?
I've done rotors/pads on all of my cars, and never once ran into this.

 

Neglect, the fact that it's a 20 year old platform, and repeated mechanical wear. Doesn't shock me in the least.

Edit: I just gotta ask, any of these vehicles you speak of, do they have the same age, neglect, and corrosion as the Barnacle? Just saying, rust and corrosion are game changing.

 

There are several reasons for this. One as mentioned is age, the other is it is a Jeep. Who knows where it has been. It might be worth noting that the design of disc brakes has changed so that this doesn't happen. Somewhere along the line, improvements have been made so this doesn't happen