W250 3/4 Ton Pickup 4WD V8-318 5.2L VIN R 4-bbl (1982)
Brake Master Cylinder: Service and Repair
Master Cylinder Bleeding
Aluminum Master Cylinder
For additional information see Bench Bleeding Notes. See: Fundamentals and Basics
Fig 3 Bench Bleeding Master Cylinder
NOTE: It is not necessary to bleed the entire hydraulic system after replacing the master cylinder if the master cylinder has been bench bled and refilled
prior to installation.
1. Clamp master cylinder in vise and attach bleeding tubes.
2. Fill both reservoirs with approved brake fluid.
3. Using a brass rod or wooden dowel, depress push rod slowly and then allow pistons to return under pressure of springs.
4. Repeat several times until all air bubbles are expelled.
5. Remove bleeding tubes from cylinder, plug outlets and install caps.
6. Remove from vise and install master cylinder on vehicle.
Cast Iron Master Cylinder
For additional information see Bench Bleeding Notes. See: Fundamentals and Basics
Fig 2 Cast Iron Master Cylinder (Top View)