Hydraulic System 1577. Reinstall the filler cap and fully open the ball valve.8. Prime the pump (see Priming a New Pump on page 136).9. Start the engine.Inspecting Hydraulic CylindersYou must inspect all hydraulic cylinders at least once a month.When you do so:1. Make sure that the ball valve on the suction line is completely open before starting the engine.2. Make sure that connections between all hoses and pipes are tight, and that no oil is leaking.Leaking or otherwise faulty cylinders must be repaired or replaced immediately.3. Make sure that all cylinder caps are firmly set and that there are no leaks.4. Using a straight edge, make sure that cylinder rods are straight.5. Lubricate and inspect all cylinders’ mounting points (pins, retaining bolts, etc.).Detecting Cylinder Internal LeaksAn internal leak is caused by a damaged seal inside the hydraulic cylinder (see 1 on Figure 5-37).Because the cylinder is leaking oil inside (bypassing), a certain amount of pressure is lost, reducingthe efficiency of the cylinder and its capacity to push and/or pull.If the packer cylinders are bypassing, the seal inside the cylinder may need to be replaced.To detect internal leaks in packer cylinders:1. Apply all safety measures, and set the parking brake.Caution! Failure to open the ball valve may seriously damage the pump and the hydraulic system.Danger! Always lock out and tag out the vehicle when inspecting or performing maintenance onthe vehicle (see Locking Out and Tagging Out the Vehicle on page 12).Warning! Failure to open the ball valve may damage the hydraulic system.