TACHOMETER GP-ELECTRIC 1889315 - Caterpillar

SUSPENSION CONTROL VALVE
1. Port to Hoist Circuit 2. Port to Rear Suspension 3. Test Port 4. Port to Front Suspension 5. Pressure (Pump) Port 6. Relief Cartridge 7. Spare Relief CartridgeThe spare relief cartridge (7) is left in place for convenience. However, it is cartridge (6) which controls inlet pressure.
SUSPENSION CONTROL VALVE
1. First Stage (Front Suspension) 2. Second Stage (Rear Suspension)
SUSPENSION CONTROL VALVE JOINING ARRANGEMENT
8. First Stage Valve 9. Plug 10. Second Stage Valve 11. Adaptor 12. PortThe load check valve is removed from the second unit and a plug (9) is installed in its place. A plug is removed from port (12) in the first unit so the tank passages are interconnected. An adapter (11) is installed to allow flow from the first stage spool to pass to the second.The methods of actuation (pilot mechanisms) and the resulting flows in and out of the systems are as described previously.Restrictor/Check Valve
RESTRICTOR/CHECK VALVE
1. Cap 2. Body 3. Spring 4. Poppet 5. Inlet PortWhen the suspension control valve is in the "raise" position oil flows into the suspension cylinders and accumulator through the external restrictor/check valve. Oil enters the valve at port (5) and lifts the poppet (4) off its seat allowing full forward flow. When the suspension valve is in the "lower" position oil flowing out of the cylinders and accumulator must pass through the hole in poppet (4). The poppet itself is seated.This action allows the suspension height to increase quickly when "raise" is selected and to reduce relatively slowly (and under control) when "lower" is selected. When "raise" is selected the suspension cylinders have to overcome the weight of the tractor unit bearing down on them. When "lower" is selected the weight assists the levelling action which would be very rapid if the release of oil from the cylinders was not restricted.
RESTRICTOR/CHECK VALVE - D250B/D300B
RESTRICTOR/CHECK VALVE - ALL EXCEPT D250B/D300BFront Suspension Accumulator
ACCUMULATOR
1. Nitrogen Charging Valve 2. End Cap 3. Nitrogen Chamber 4. Cylinder Tube 5. Piston 6. Oil Chamber 7. End Cap 8. Inlet Port 9. Holes 10. Restrictor/Check ValveThe accumulator contains a sealed piston (5) which moves along the bore of cylinder tube (4). Chamber (3) is charged with nitrogen gas through the charging valve (1). When the accumulator is initially charged with nitrogen (pre-charged) the piston is pushed to the bottom of the cylinder tube.When the accumulator is installed on the truck it receives pressurised oil through port (8). This oil forces the piston back up the bore of the cylinder tube. The nitrogen in chamber (3) is further compressed until its pressure rises sufficiently to balance the oil pressure. During normal operation the compressed nitrogen acts as a source of stored energy to provide the necessary "spring" and absorb shock.The accumulator end cap has an integral restrictor/check valve (10). When oil is flowing into the accumulator the retrictor/check valve lifts off its seat and allows free flow into the oil chamber (6). When oil is flowing out of the accumulator the restrictor/check valve is