You're adjusting an automatic slack adjuster that has a square adjusting bolt but doesn't have the round "button." You should first remove all of the following EXCEPT
- the pawl
- the adjusting bolt ✓
- the spring
- the hex cap
Answer: B. the adjusting bolt
Remove the hex cap, the spring and the pawl — but leave the adjusting bolt in place.
Why this is the answer
The handbook describes slack adjusters with a square adjusting bolt at the bottom of the body. On units where the hex cap has no round button you can pry up, the cap, spring and pawl all have to come off so the pawl no longer meshes with the internal teeth. Once those parts are disengaged, you can make the adjustment with the bolt itself — counter-clockwise until the lining meets the drum, then half a turn clockwise to restore running clearance. Because the bolt is the part you turn, it is the one piece you do not take off.
Why the other answers are wrong
- A. the pawl — The pawl has to come off, since it meshes with the internal teeth and has to be disengaged before any adjustment can be made.
- C. the spring — The spring is listed along with the cap and pawl as parts that must be removed when there is no button to hold.
- D. the hex cap — The hex cap is the cover over the spring and pawl, so it comes off first when there is no round button to pry up.
Remember it
No button to hold? Then the cap, spring and pawl all come off — the bolt is what you turn, not what you remove.