TIP GP-LONG 6Y6767 - Caterpillar

Illustration 1 g01406914
(A) Main Relief ValveThe main relief valve is located in the inlet section of the main control valve.
Illustration 2 g01406917
Typical Main Relief Valve (1) Inlet passage. (2) Valve. (3) Passage to tank. (4) Passage. (5) Spring. (6) Locknut. (7) Adjustment Screw.Pressure oil flows into passage (1). The oil acts against the left side of valve (2), which is held closed by spring (5) .When an outside force causes pressure in any of the cylinders to rise, the increase in pressure is also sensed in passage (1). As the pressure rises above the pressure setting, the oil overcomes the force of spring (5) and valve (2) will move to the right.Oil in passage (1) then flows past the open valve, through passage (3), and back to the hydraulic oil tank.The pressure in the cylinders can not increase further. When oil pressure returns to a level below the pressure setting, spring (5) moves valve (2) to the left and onto the seat.The relief valve pressure setting can be adjusted by loosening locknut (6). Turn adjusting screw (7) clockwise in order to increase the pressure setting. Turn adjusting screw (7) counterclockwise in order to decrease the pressure setting.