Weird drum and shoe wear

97 xj, 4.0 auto 8.25 rearend

I replaced the drums and shoes using all new hardware about a year ago and had them off recently to check the self adjusters and noticed really odd wearing on the shoes and drum. The self adjusters were messed up, the cable guide had slipped off but I got that fixed and it seems to be holding now but not sure if that caused the issue.

The shoes had a rather high protrusion(running parallel) in a narrow section towards the center running the full length of the shoe, a cross section view would look like, _-_ . While the drum had the indentation for that same spot, my first thought was something had gotten stuck between the shoe and drum but then that didn't seem to make sense. The drum is much harder material why would one spot of the shoe not wear and create a high spot? Could it be a shoe defect? It is not terrible deep of an indention on the shoe but deeper than what I think can be turned down easily. I figure if a rock or something did get in between then the shoe would have the indentation not the other way around.

I hope my descriptions make sense, I asked a few people and they drew a blank so I don't know if this is common or what...

The shoes conform to the drum.

I have seen hardware get loose and score the drum, no chance for it to get embedded in the friction material.

look at the rivets in the shoes. they are usually recessed well below the surface of the shoe, and when you wear them down to the point the rivets start touching, you will get the same exact result.
probably a defective shoe with a high rivet head that is right in that patch somewhere.
if that is the case you have a good case to take them back for replacements.
a rock would have to have been there a very long time and would have made a lot of racket.

Did you put Jeep shoes on the rear? The reason I ask is I just finished chasing a year long problem with rear shoe lock-up on my 98 with no smoking gun. The adjusters were always messed up and after 15 minutes or normal driving the rears would begin to lock up, even under light braking. I had zero axle seal seepage and tons of material on the shoes. It ended up being sub-standard brake shoes that I bought from the aftermarket. I bit the bullet and bought Jeep OEM shoes and hardware and it's been perfect ever since. Just food for thought. Defective shoes are definitely out there. I threw away the set with over 80% of the lining left.

iwannadie said:

... The drum is much harder material why would one spot of the shoe not wear and create a high spot? ... if a rock or something did get in between then the shoe would have the indentation not the other way around...

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Any foreign bits will embed themselves into the softer of the two materials and grind away at the harder...

Case in point: We have hole laps here at work that are used to gradually lap a hole to a specific size. The laps are made of copper and the lapping compound is an abrasive that embeds itself into the copper...

Another: I bought a used Honda CR 500 some years ago. The previous owner rode it almost exclusively at Glamis. There was a short piece of plastic that hung down inside the rear fender and covered the swing arm. Over the years the sand had embedded itself into the plastic and actually wore a hole through the aluminum swing-arm. I had to get it welded back up...

Good info, makes a lot of sense to think of something getting stuck and imbedding itself into the softer shoe material and then wearing away the drum. When I first thought about it I just imagined the shoe material being worn away first and any foreign object would have worn the indentation into the shoe. Also, the chance of a defective shoe, it honestly seemed like such a perfect indentation in the drum that I am leaning towards the defective shoe. I will be taking it apart this week I hope to try and see what is going on.

I used napa parts, Shoes UP UP538 Drums ND 4401633, I sprung for the better versions of their parts.

No matter how good parts are, they may be defective. Most of the premium parts from your local parts stores are lifetime warranty. I would consider contacting them and talking to them about it. As with most people, I am sure you do not have the original box for the shoes anymore? Sometimes, they require a receipt but you should be able to walk out of the store with a new set of shoes ( swapped for your old/defective ones) for no charge.

Johnnie Walker said:

No matter how good parts are, they may be defective. Most of the premium parts from your local parts stores are lifetime warranty. I would consider contacting them and talking to them about it. As with most people, I am sure you do not have the original box for the shoes anymore? Sometimes, they require a receipt but you should be able to walk out of the store with a new set of shoes ( swapped for your old/defective ones) for no charge.

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I am more worried about the drum replacement, it was not cheap.