797F Off-Highway Truck: Check the oil filter for brake actuation oil. and Check the oil filter for the hoist and brake cooling oil.

1.-Check the oil filter for brake actuation oil.

(1) Oil filter for the brake actuation oil

Remove oil filter (1) for the brake actuation oil. Inspect oil filters (1) for foreign material. Cut the oil filter open, if necessary.
Note: Oil filter (1) for the brake actuation oil has an oil bypass valve. The bypass valve allows the oil to bypass the oil filter elements whenever the pressure difference between the inlet oil and the outlet oil becomes too high. Any oil that does not flow through the filter element goes directly into the hydraulic circuit. Dirty oil can cause sticking valves and restrictions in valve orifices. The pressure sensor will notify the operator of a restriction.

Problem: Rubber particles are found.

Probable Cause

• Seal failure
• Hose failure

Problem: Shiny steel particles are found.

Probable Cause

Shallow retarding arrangement(2) Gear pump for the brake and rear axle lubrication

Steep retarding arrangement(2) Gear pump for the brake and rear axle lubrication

• Mechanical failure of brake actuation pump section (2)

2.-Check the oil filter for the hoist and brake cooling oil.

Steep retarding arrangement(1) Oil filters for the hoist and brake cooling oil

Shallow retarding arrangement(1) Oil filter for the hoist and brake cooling oil

Remove oil filter (1) for the hoist and brake cooling oil. Inspect oil filter (1) for foreign material. Cut the filter open, if necessary.
Note: Oil filter (1) for the hoist and brake cooling oil has an oil bypass valve. The bypass valve allows the oil to bypass the oil filter element or the screen whenever the pressure difference between the inlet oil and the outlet oil becomes too high. Any oil that does not flow through the filter element or through the screen goes directly into the hydraulic circuit. Dirty oil can cause sticking valves and restrictions in valve orifices. The pressure switch will notify the operator of a restriction.

Problem: Rubber particles are found.

Probable Cause

• Seal failure
• Hose failure

Problem: Shiny steel particles are found.

Probable Cause

Location of the gear pump for hoist and brake cooling for the shallow brake arrangement

Location of the gear pump for hoist and brake cooling for the steep brake arrangement

• Mechanical failure of gear pump (2) for the hoist and for the brake cooling system

Refer to "Check the screens for the brake oil coolers".

MARYGAR