Brake pad wear, what's "normal"

[gstirling]

doing some front end maintenance on my M936A1 and noticed my front brake pads were worn more on the leading edge and trailing edge than in the middle. TM states pads are good till the bevel is gone. my bevel is near perfect in the middle of the pad but at least 30-40% gone on the ends. like they do not fit the hub well or shift while braking causing higher wear on the ends? my guess is, when the bevel is worn out in the middle the ends will just about be hitting the backing (all pad material gone). is this "normal"? truck has low miles (if accurate) and is running the pads that came from the army on it. both sides are worn the same. braking feels fine, and the truck stops well. thoughts???

 

[Mullaney]

doing some front end maintenance on my M936A1 and noticed my front brake pads were worn more on the leading edge and trailing edge than in the middle. TM states pads are good till the bevel is gone. my bevel is near perfect in the middle of the pad but at least 30-40% gone on the ends. like they do not fit the hub well or shift while braking causing higher wear on the ends? my guess is, when the bevel is worn out in the middle the ends will just about be hitting the backing (all pad material gone). is this "normal"? truck has low miles (if accurate) and is running the pads that came from the army on it. both sides are worn the same. braking feels fine, and the truck stops well. thoughts???

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Properly adjusted shoes help with wear. The goal is to get as much shoe in contact with the drum as possible. Sounds like yours might not be "quite right" since all the wear is in the center of the shoe.

You mentioned brake pads. Sounds like you have disc brakes but I haven't seen a 936 with those...

One thing that might be useful is going through the wedge brakes so everything is "free" and properly releases when you step off the brakes. Found a little video about that.

 

[charlesmann]

Since there is only 1 brake chamber, the shoe pads should wear from the chamber plunger/wedge, and working its way to the middle, then to the idle/pivot point of the shoes.

I saw a lot of uneven wear with s-cams. having only a single actuating point, cause the shoes to wear more at the point, than the pivot point.

The rear axles on these mil trucks have 2 chambers, so a more even wear is achieved if properly adjusted.

For the front shoes, I dont think they can be flipped, so an even wear happens.

 

[gstirling]

.
Properly adjusted shoes help with wear. The goal is to get as much shoe in contact with the drum as possible. Sounds like yours might not be "quite right" since all the wear is in the center of the shoe.

You mentioned brake pads. Sounds like you have disc brakes but I haven't seen a 936 with those...

One thing that might be useful is going through the wedge brakes so everything is "free" and properly releases when you step off the brakes. Found a little video about that.

Ahh my bad , should have said bake shoes, not pads, so yes its drums....LOL... thanks on the video, will check it out.

 

[Steelreaper80]

Side question, when do the brake drums need to be replaced?

 

[simp5782]

When they show signs of heat cracking or fall below thr minimum thickness