PILOT 7P9272 - Caterpillar

Location of components in 8C7944 or 8C7945 Grapple. Adjustment Procedures
The grapple snubber exerts hydraulic pressure which expands a mechanism in the pin joints of the crosshead assembly. This acts as a brake which retards the swing of the grapple. The amount of retardation can be adjusted by using the following procedure.
Procedure 1 - Grease Adjustment
The snubber may be adjusted to the desired snugness by turning the screw in relief valve (14).
1. To tighten the snubber, turn the screw in relief valve (14) clockwise 1/4 turn. Apply grease to leakproof fitting (16) until grease is released through the vent hole. Fitting (16) must be a leakproof fitting to maintain continuous pressure.2. To loosen the snubber, turn the screw in relief valve (14) counterclockwise until the grapple swings freely as desired. The relief valve is preset at 5500 kPa (800 psi). Each 1/4 turn increases/decreases the preset pressure 13780 kPa (2000 psi).Procedure 2 - Manual Adjustment
1. Tighten nut (12) to achieve the desired snugness.Maintenance Procedures
1. Bushings (21) in crosshead (1) should be lubricated every 50 hours. Apply grease to the fittings indicated in the illustration.2. The grapple snubber should be adjusted as required.If continuous pressure cannot be maintained, either the grease fitting seals may be faulty or seals (3) and (4) and the retainer may be worn, brittle or damaged.
Friction Disc Wear Limits
Friction discs (7) must be replaced before their thickness becomes less than 1.57 mm (.062"). If the friction discs are flush with retainers (8), the thickness is less than 1.57 mm (.062").
Friction Disc Replacement
1. Lower grapple assembly (18) until the tip of the tongs rest on the ground. Support the grapple. Carefully continue lowering the grapple assembly until the weight of the unit is off of pins (19).2. Turn the screw in relief valve (14) counterclockwise until all pressure in the crosshead is relieved. Record the number of turns required to release all the pressure. Replace only one set of friction discs at a time.3. Remove cotter pin (13) and nut (12).4. Pull the pin out until friction discs (7) on both sides are free. It is not necessary to remove the pin completely.5. Install new friction discs, and reinstall the pin that holds them. Install nut (12), and tighten it to a torque of 540 N m (400 lb ft).6. Repeat Steps 3 through 5 for the other pin and discs.7. Return the screw in relief valve (14) to its original location as recorded in Step 2.8. Adjust the snubber as indicated above.