308C CR Excavator Hydraulic System – Relief Valve (Pilot) – Remove and Install

Removal Procedure

Start By:

  1. Relieve the hydraulic pressure in the system. Refer to Disassembly and Assembly, “Hydraulic System Pressure – Release”.


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.

------ WARNING! ------

Personal injury can result from hydraulic oil pressure and hot oil.

Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system.

Make sure all of the work tools have been lowered to the ground, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.


    Illustration 1 g00907598

  1. Remove relief valve (1) from filter base (2) .

    Illustration 2 g00907600

  1. Remove O-ring seals (3) from relief valve (1) .

Installation Procedure

    Illustration 3 g00907600

  1. Install O-ring seals (3) on relief valve (1) .

    Illustration 4 g00907598

  1. Install relief valve (1) in filter base (2). Tighten to a torque of 118 ± 10 N·m (87 ± 7 lb ft).