I-2 / I-3 Valve Reference Material
August 2019 - 89130 v.3.0 59
Sequence of Events
(continued)
Up Stop 1. The up slow solenoid de-energizes to stop the car. The pump runs slightly longer on a
timed delay to provide a valve stop instead of a pump stop. See Figure 10.
2. With pressure equalized on both ends of the up pilot piston, the spring parks the pis-
ton in the down position. In this position, the openings of the up slowdown and level-
ing adjuster are closed, and the opening of the up stop adjuster opens.
3. The up stop adjuster allows flow out from behind the regulator piston and causes the
pressure to drop.
4. Decreased oil pressure on the back of the regulator piston allows pressure from the
jack (with the spring force) to push the piston against the low pressure adjustment
stud allowing full bypass. At the same time, the check valve piston closes.
5. The opening at the stop adjustment controls the stop rate. The wider the opening, the
faster the stop.
Figure 10 - Up Stop Diagram
TANK
CONTROL FLOW
Relief Pressure Adjustment Screw
High-pressure
Relief Pilot
Up Slow Solenoid
(Closed)
Up Slowdown
Adjustment
Pressure
Control
Piston
Up Stop Adjustment
Up Pilot Piston
Up Fast Solenoid (Closed)
Up Start Adjustment
Up Leveling Speed Adjustment
Check Valve Piston
PUMP JACK
Regulator Piston
Low
Pressure
Adjustment
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