INJECTOR GP- 1888739 - Caterpillar

Illustration 1 g01523019
Location of steering metering pump under the left hand platformCovers have been removed for clarity.The steering metering pump is located on the base of the steering column under a cover below the cab. The resilient mounting of the metering pump will prevent vibration damage and noise.
Illustration 2 g00282859
Steering metering pumpNEUTRAL position (1) Inner spool (2) Drain outlet to tank (3) Left turn port (4) Outer sleeve (5) Right turn port (6) Inlet (7) Passage (8) Stator (9) Rotor (10) Passage (11) Drive (12) Pin (13) Centering springs (A) Control section (B) Metering sectionThe steering metering pump is made up of the following two sections:
Control section (A)
Metering section (B) The two sections are connected by hydraulics and by mechanics.Pump oil from the steering control valve goes through inlet (6) into control section (A). When the steering wheel is turned, control section (A) sends oil to metering section (B). Metering section (B) produces a specific amount of oil flow. Metered oil from metering section (B) is then directed by control section (A) to either left turn port (3) or right turn port (5). This oil becomes pilot oil for the steering control valve. As the steering wheel is turned faster, there is an increase in the flow of pilot oil. The steering cylinders will move farther with increased speed.Oil Flow
Control section (A) of the steering metering pump is a closed center type. When the steering wheel is in the NO STEER position, there is no alignment between the holes in sleeve (4) and the passages in spool (1). However, a small amount of pump oil from inlet (6) is allowed to flow through the center position of the steering metering pump. This small amount of oil flow (thermal purge) keeps the steering metering pump full. This will give a response time that is quick to steering demands. The thermal purge also helps keep the pilot oil lines to the steering control valve and the steering metering pump warmed during cold weather operations.Right Turn
Illustration 3 g00287150
Steering metering pumpRight turn (1) Inner spool (4) Outer sleeve (5) Right turn port (6) Inlet (7) Passage (8) Stator (9) Rotor (10) Passage (11) Drive (12) Pin (13) Centering springs (A) Control section (B) Metering section
Illustration 4 g00282755
Spool and sleeve (1) Inner spool (4) Outer sleeve (14) Holes for pin (12) (15) Small holes for oil flow (16) Grooves for oil flow (17) Slots for centering springsWhen the steering wheel is turned clockwise, spool (1), pin (12) and drive (11) start to turn. Sleeve (4) will not turn because spool (1) will turn inside sleeve (4). Small holes (15) in sleeve (4) will be in line with grooves (16) in spool (1). The thermal purge is blocked when spool (1) and sleeve (4) rotate. Pump oil from inlet (6) goes through small holes (15) in sleeve (4) into grooves (16) in spool (1). The oil in grooves (16) goes out through other small holes (15) in sleeve (4) and into passage (10). Oil flows through passage (10)