Diesel Mechanic how-to
How to Check Air Brake Pushrod Stroke
Out-of-adjustment brakes are one of the most common roadside violations.
Out-of-adjustment brakes are one of the most common roadside violations. In short: park; build; mark, then complete the remaining steps below.
Step by step
Park on level ground, chock the wheels and release the parking brakes.
Build air pressure to the specified range (often 90–100 psi), then shut off the engine.
Mark each pushrod where it exits the chamber.
Have a helper make and hold a full brake application.
Measure how far each mark moved.
Compare with the maximum stroke for the chamber size and type.
Adjust or repair brakes that exceed limits, and find out why automatic slack adjusters didn’t keep up.
Safety reminders for diesel mechanics
- Chock wheels and support vehicles with jack stands. Never rely on a jack alone
- Lock out and tag out vehicles and equipment during repairs
- Wear eye protection and gloves when working with fluids and pressurized systems
- Cage tires before inflating split-rim or multi-piece wheels
Key terms
Compression ignition · DPF · Regeneration (regen) · DEF · SCR · EGR: see the full diesel mechanic glossary.