How can you determine applied pushrod stroke?
- (a) Note how the reading of the application pressure gauge has changed.
- (b) See how much the visible pushrod length increases when the brakes are applied.
- (c) See how far a mark on the pushrod travels when the brakes are applied.
- Either (b) or (c) ✓
Answer: D. Either (b) or (c)
You can determine applied pushrod stroke by either measuring the increase in pushrod length or checking how far a mark on the pushrod travels, so the correct choice is the one that allows either method.
Why this is the answer
The handbook describes two accepted checks. With the brakes released, you either put a mark on the pushrod where it leaves the brake chamber or measure from the clevis pin to the brake chamber face. Then you apply the brakes and compare. Applied stroke is either the distance from the mark to the chamber face or the difference between the two length readings. Both methods measure the same pushrod movement, so either one works.
Why the other answers are wrong
- A. (a) Note how the reading of the application pressure gauge has changed. — A change in the application pressure gauge reading does not show how far the pushrod moved; the handbook uses a mark or a length comparison instead.
- B. (b) See how much the visible pushrod length increases when the brakes are applied. — This is one accepted check, but as a standalone choice it omits the mark-travel method, so it does not give the full answer the handbook allows.
- C. (c) See how far a mark on the pushrod travels when the brakes are applied. — This is the other accepted check, but by itself it leaves out the pushrod-length comparison, so it is incomplete as the answer.
Remember it
Two ways, one stroke: watch the mark move or watch the measured length grow.