What is the difference between free stroke and applied (power) stroke?

• A.Free stroke is measured only on the trailer
• B.Free stroke is the initial pushrod movement before the shoes contact the drum, while applied stroke is the total travel measured under a full brake application
• C.Applied stroke is the distance the pedal moves inside the cab
• D.There is no difference between the two terms

Why

Some travel is spent taking up clearance, and the rest delivers and maintains braking force. Measuring total applied stroke against the chamber limit is the dependable adjustment check used in inspections.

Manual topic: Air Brakes - Slack Adjusters · From the Air Brakes practice bank (AB-169).

Practice this subject as a full test

More Slack Adjusters & Pushrod Stroke questions

• What does a slack adjuster do in an S-cam air brake?
• How do you measure pushrod stroke (applied stroke) when checking brake adjustment?
• For many common brake chambers with a manual slack adjuster, about what pushrod stroke is the commonly cited maximum limit?
• What happens when pushrod stroke becomes excessive?
• When checking slack by hand, how much free movement at the slack adjuster suggests the brake needs adjustment attention?