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Common Brake Out-of-Service Issues — and how to catch them first.

Brake defects account for the largest share of out-of-service violations at CVSA inspections in Ontario. Nearly all are preventable with regular measurement and maintenance.

Brake stroke / pushrod travel

Standard stroke limit: typically 1.75 inches (type 20/24) or 2 inches (type 30)
Measured with the brakes applied at 80-100 PSI
Automatic slack adjusters still fail: they compensate for lining wear but can't fix a worn chamber
Measure, don't guess: visual inspection is not sufficient for CVSA compliance

Lining and drum condition

Minimum lining thickness varies by chamber size (typically 1/4 inch minimum)
Drums must be within maximum diameter stamp and free of cracks, heat checks
Oil or grease contamination on lining requires replacement, not cleaning
Mismatched lining materials on the same axle reduce braking efficiency

Air system defects

Air leaks exceeding 4 psi/minute (single) or 6 psi/minute (combination)
Compressor not building to governor cut-out pressure (typically 120-125 PSI)
Faulty or missing air dryer allowing moisture into the system
Spring brake chambers that don't release or apply properly
Treadle valve (foot valve) not returning to zero pressure

ABS / EBS defects

ABS warning lamp not illuminating during bulb check at startup
ABS warning lamp staying on while driving (active fault code)
Open or shorted wheel-speed sensor circuits
Modulator valve failure (won't release or apply)
Mismatched or incorrect ECU software calibration

Questions?

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