General Guidelines

P4 MM 42.08; 5th Generation Cascadia MM
Warning: Failure to lubricate slack adjusters could lead to dragging brakes or a brake failure, resulting in property damage, personal injury, or death.
Important: Perform a brake inspection following the instructions in this group before lubricating the slack adjusters.
Note: If equipped with an extended-maintenance Q Plus™ brake system, the slack adjuster will not have a grease fitting. These slack adjusters use a special NLGI Grade synthetic polyurea grease and do not require lubrication for 3 years or 500,000 miles (800 000 km), whichever comes first. The extended-maintenance slack adjusters are lubricated during the brake reline service interval. For service and lubrication instructions, see the vehicle workshop manual.

For slack adjusters with grease fittings and for operating temperatures above –40°F (–40°C), use an NLGI Grade 1 clay-base grease, or an NLGI Grade 1 or 2 lithium-base grease.

For slack adjusters with grease fittings and for operating temperatures below –40°F (–40°C) and above –65°F (–54°C), use an NLGI Grade 2 synthetic oil, clay-base grease.

Lubricate the slack adjuster at the grease fitting until grease is forced past the pressure-relief capscrew or past the gear splines around the inboard snap ring. See Fig. . Follow the steps below for proper greasing.

  1. Brake Chamber

  2. Clevis

  3. Actuator Rod

  4. Boot

  5. Pressure-Relief Capscrew, Gasket, Pawl Spring, and Pawl

  6. Manual Adjusting Nut

  7. Grease Fitting (or plug)

Fig. 1, Meritor Automatic Slack Adjuster

Note:
Parent topic: Lubrication of the Meritor Slack Adjuster
Document Number: 0000103291
Manual Publication Date: 2025-07-14
Topic Publication Date: 2026-05-06