Pilot oil filters are located on the left side of the front frame, in the transmission compartment.
Pilot oil filters
(2) Inlet passage
(3) Outlet passage
Pilot oil filter base
(6) Bypass valve
Oil from the hydraulic tank flows to the brake and pilot section of the gear pump. The gear pump sends oil through the pilot oil pressure reducing valve to the pilot oil filters.
Oil flows through inlet passage (2). The oil fills the space between the inside of housings (5) and elements (4). During normal operation, the oil flows through elements (4) and out outlet passage (3) to the remainder of the pilot hydraulic system. Elements (4) stop any debris that is in the oil.
If filter elements (4) become full of debris, the restriction to the flow of oil causes a pressure increase inside the filter. The pressure of the oil causes bypass valve (6) to move against the force of spring (7) .
The oil then flows past the open bypass valve to the remainder of the pilot hydraulic system. When the oil does not flow through the filter elements, the debris in the oil will damage other components in the hydraulic system.
Use correct maintenance in order to make sure that elements (4) do not become full of debris. If elements (4) are full of debris, the flow of filtered oil to the pilot hydraulic system is stopped.