M313C, M315C, M316C, M318C and M322C Excavators and M318C and M322C Material Handlers Hydraulic System Caterpillar

If the swing brake is not adequate for the job requirements, adjust the torque of the swing brake. The torque is adjusted by changing the pistons. The pistons provide the following types of braking:

• Weak

• Normal

• Hard

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Illustration 1	g00294418
Swing Pump (1) Plug (2) Spring (3) Piston

1. Start the engine.

2. Position the machine on level ground.

3. Stop the engine.

4. Release the pressure in the hydraulic system. Refer to Testing and Adjusting, "Hydraulic System Pressure - Release".

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NOTICE
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates.

5. Remove plug (1) from the swing pump.

6. Use a magnet to remove spring (2) and piston (3) .

7. Replace piston (3) with the new piston of the desired braking torque.

8. Install spring (2) and plug (1). Tighten plug (1) to the specified torque.

9. Repeat Steps 2 through 8 for the piston on the opposite side of the regulator. Use the same torque on both sides of the regulator.

   Note: All machines are equipped with a standard piston. The braking torque is controlled by the depth of the groove on the head end of the piston. A piston with a deeper groove will increase the braking torque. The groove depth is marked on the head end of the piston.

   Pistons are available to adjust the braking torque in one of the following ways:

   • Increase

   • Decrease

139-9222 Piston

Braking torque ... Normal

Groove depth ... 1.0 mm (0.039 inch)

139-9223 Piston

Braking torque ... Weak

Groove depth ... 0.8 mm (0.032 inch)

139-9224 Piston

Braking torque ... Hard

Groove depth ... 1.35 mm (0.053 inch)