Inspection of the In Service

Apply and release the brakes several times while observing the slack adjuster. The slack adjuster and brake actuator should move freely, without binding or interference, and should return to the full released position. Observe the looseness that exists between the clevis and adapter bushing and the yoke and link pins and their mating parts (clevis, body, link). Replace these parts if looseness appears excessive. Make certain the brake actuator pushrod jam nut is tightened securely.

Inspect the slack adjuster for physical damage, paying attention to the link, boot, and clevis. If any components are damaged, repair or replace them as necessary.

Measure the brake actuator pushrod stroke while making an 80 to 90 psi (552 to 621 kPa) brake application. Actuator pushrod strokes should not exceed the values shown in Table. and Table.. To achieve the correct pressure for this test, build the system pressure up to a 100 psi (690 kPa). Shut down the engine. Fan the brakes to attain a 90 to 95 psi (621 to 655 kPa) reading. Make and hold a full brake application while the strokes are checked.

Table 1, Actuator Stroke–Standard Stroke

Actuator Stroke–Standard Stroke
Brake Actuator Size	Recommended Maximum Operating Stroke (Inches)
30	2
24	1-3/4
20	1-3/4
16	1-3/4
12	1-3/8

Table 1, Actuator Stroke–Standard Stroke

Table 2, Actuator Stroke–Long Stroke

Actuator Stroke–Long Stroke
Brake Actuator Size	Recommended Maximum Operating Stroke (Inches)
30 Long Stroke	2-1/2
24 Long	2
24 Long Stroke	2-1/2
20 Long	2
16 Long	2

Century Class Trucks Maintenance Manual

Table 1, Actuator Stroke–Standard Stroke

Table 1, Actuator Stroke–Standard Stroke

Table 2, Actuator Stroke–Long Stroke

Table 2, Actuator Stroke–Long Stroke