SPARK PLUG 4W4958 - Caterpillar

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.
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.
When problems with the hydraulic pressure in the brake system occur, one possible cause may be a malfunction in the backup relief valve.Reference: Refer to the Service Manual module Testing and Adjusting, "System Pressure - Release" before performing the following procedure.This test procedure must be done on a hydraulic test bench. The test bench must have a hydraulic pump that will supply at least 38 4 L/min (10 1 US gpm) of oil flow. The pump must supply at least 22750 450 kPa (3300 65 psi) of oil pressure.The test should be performed with the oil at a temperature of at least 49° 3°C (120° 5°F).
Illustration 1 g00858290
Backup Relief Valve (Brake System) (1) Retainer assembly (2) Nut (3) Tank return port (4) Pressure port
Remove the backup relief valve for the brake system from the machine. The backup relief valve is located under the cab on the right side. Removal of the floorplate that is outside the cab on the right side may be necessary.
Install a plug into one pressure port (4) on the relief valve.
Install the pressure hose from the test bench into the other pressure port (4) on the relief valve.
Install the drain hose from the test bench into tank return port (3) on the relief valve.
Start the hydraulic pump. Apply oil flow and pressure into the relief valve. At a flow rate of 38 4 L/min (10 1 US gpm), the oil pressure should be 22750 450 kPa (3300 65 psi) before the relief valve releases the pressure back to the tank. If the pressure measurement is not within the tolerance, adjust the relief valve. When the relief valve is open, the oil pressure at tank return port (3) should measure 70 7 kPa (10 1 psi).Note: In order to adjust the relief valve, loosen nut (2). Turn retainer assembly (1) clockwise in order to increase the pressure setting. Turn the retainer assembly counterclockwise in order to decrease the pressure setting. When