Trailer Brakes: Slack Adjusters, Chambers, and the Spring Brake
Trailer brake faults cause DOT violations and runaway risk. We cover slack adjusters, chambers, and the spring brake system.
Out-of-adjustment slack adjusters
Trailer slack adjusters that exceed legal pushrod stroke are the most common trailer brake violation. Automatic slack adjusters should self-adjust, but a worn cam, clevis, or seized adjuster means they stop adjusting. We measure stroke at each wheel and find why an adjuster stopped — not just crank it down, which masks the underlying wear and fails again in a week.
Air chambers and spring brakes
We verify correct chamber size and type per axle, check for air leaks at the chamber and the relay valve, and test the spring brake (parking) function. A trailer that won't release its parking brakes usually has a leaking spring brake valve or a clogged control line; a trailer that won't hold usually has a chamber or foundation brake fault.
Relay and quick-release valves
Slow application or release points to the relay or quick-release valve, not the chambers. We test timing and replace the valve, which is faster and cheaper than chasing chambers that test fine.
Our mobile diesel technicians carry the tools and parts to diagnose and fix this on the shoulder or at your yard — 24/7/365 across Colorado, Wyoming, and Texas.
(303) 476-3622Trailer light faults are the most common DOT violation. We cover the 7-way, ground, and harness faults behind most failures.
A sagging or bottoming trailer suspension damages cargo and tires. We cover air ride ride height, bags, and linkage.
Air bag failure sags the trailer and damages cargo. We cover finding the leak and when to replace vs. repair.
Landing gear that won't crank or won't hold strands the trailer. We cover the gearbox, legs, and the cross-shaft.