Uneven wear on drives brakes

With everything you just said and the wasteful way things are done these days I think all these mega companies should have a recycle program. Just run the truck through a shredder after it hits 3 years old and ship the scrap back to the manufacturers to reprocess into a replacement and repeat.

 

I can’t tell any difference from pictures. I’m wondering if the drums are wearing uneven. I’ve had mine get grooves on a couple, and none on others. Caused from heat I guess. Yet shoes aren’t always worn more. You can run your finger across them, between the shoes. Maybe the drums are worn along with shoes. Or just worn drums, and shoes are sitting inside a groove. Making them look more worn more than they are.

 

I’m not a Mechanic, but I noticed on my trailer, I only have abs sensors on one axle. Rear axle. Reading up on the system, I read that air ride systems, will have sensors on rear axle, and spring ride will have sensors on front axle. They claim because each system, works different when it comes to required brake force. So it stands to reason that the rear brakes would wear quicker, at least on my Trailer, and it seems to be the case, I’ve noticed. Your Truck probably has 4 sensors, along with 4 traction sensors that apply brakes, during a spin out. My first thought was maybe the axles running hot, but 100k, brakes should still be almost like new. Unless someone rides the brakes a lot.

 

There are a few reasons that brakes can wear unevenly. The biggest one is auto-slack
adjusters not adjusting evenly. The springs in the maxi chambers can weaken, bend or break.
When a chamber is replaced the push rod needs to be cut to the correct length as well.
If its too long or short it can effect adjustment. A faulty spring can cause a brake to adjust
not enough or too tight speeding up wear.

With auto-slack adjusters to adjust the brakes with the truck stopped build up full air pressure
and with the park brake released make a full pressure brake application. This pushes the push
rods out as far as the adjustment allows. Under a lot of driving conditions during a day the
brakes may never get applied hard enough to properly adjust themselves. Not making that
full application means the brakes are being adjusted by the park brake application.
New park brake chambers have an application from the spring comparable to around 80 PSI
but after a few months the springs weaken and the park application is comparable to a 60 PSI
or less application and a lot less if a spring is broken. A 60 PSI application is not enough to
keep the brakes adjusted properly.

With an unloaded truck try driving about 5 mph on gravel or soft ground and apply the park brake while moving and watch in the mirrors how many wheels lock up. The ones that don't lock up have weak or broken springs in the chambers.

 

Yep. I usually pump enough grease in to just start seeing it flow out around the slack adjuster. Just watch the other end. There should be a grease seal there but it doesn't always work. Grease on brake shoes is not good. Should be a grease fitting on the slacks as well. Pump until it just starts to flow out and crackle.