Newer driver of big trucks here...
My 2020 international just rolled over 100,000 so when I was having a trailer tire swapped I asked the mechanic to check the drive brakes. He confirmed what I thought I was seeing. Axle 3 is definitely wearing faster than axle 2.
How does this happen? I thought they adjusted themselves...
Uneven wear on drives brakes
Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Qbf594, Jul 8, 2020.
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Google how to adjust. Your truck brakes .for year model .it's usually going foward or backwards at 15 mph and locking them down to stop repeatedly.not letting off till stopped.
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Or a wrench
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Could be a multitude of things:
-Brakes could have been replaced on axle 2 more recently due to a blown wheel seal.
-Weight distribution on the drives during braking. ABS keeps wheels from locking. More weight transfer to an axle means it can brake harder without locking up.
-Mix match of shoes between the 2 axles. Softer friction material will wear quicker.
-Possibly a difference in cracking pressures of the drive axle relay valves. Cracking pressure is the amount of PSI from the pedal that is needed to overcome the spring in the relay valve.
There is a bit of a misconception with slack adjusters. Yes everything modern is required to have auto slacks. They adjust the shoe to drum clearance and keep it constant. However, due to the design of the chambers, they produce the same amount of force per PSI of application through out their entire stroke.stillwurkin and blairandgretchen Thank this. -
stillwurkin, Qbf594 and lester Thank this.
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stillwurkin and Qbf594 Thank this.
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xsetra Thanks this.
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Weight distribution makes sense except for I can't figure out how 2 and 3 could get very far apart since it comes thru the king pin /plate which is centered between the axles...
I'll ask on the pressure adjustment when I get the shoes replaced.
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