I hope this helps with brake caliper lubrication. For Prevosts made before 1998, which had Meritor brake calipers on the steer and tag axles, there are three designs based on the year: Pre-1985, 1985 to 1991, and 1991 to 1998. These calipers included pressure relief valves at the grease fittings. Meritor recommends lubricating the internal actuating components 2 to 4 times during the life of the lining, or every six months. Here’s how to do it:
1. Adjust the Brakes: Turn the adjusting nut on the automatic slack adjuster to move the inboard lining against the rotor (tighten the brakes).
2. Plug the Pressure Relief Valve: Hold a finger over the poppet to plug the valve. For calipers with grease fittings on the caliper and camshaft cap, first apply grease to the caliper fitting, then to the camshaft cap.
3. Apply Grease: Pump grease through the caliper fitting until it flows out of the camshaft cap.
4. Remove the Pressure Relief Valve: Take out the valve and turn the slack adjusting nut in the opposite direction to fully retract the caliper piston, forcing excess grease through the pressure relief hole.
5. Reinstall the Pressure Relief Valve: Put the valve back and adjust the brakes as per the brake adjustment procedures.
Note: This process removes excess grease from the caliper. Failing to do so can lead to brake drag and reduced lining life.
Most brake issues are due to lack of lubrication or use. While I haven’t seen failures from over-lubrication or incorrect lubrication, many issues arise from inadequate lubrication or infrequent use.
I hope this clarifies things!