SECTION X
POWER STEERING SYSTEM
steering wheel is released, the valve piston returns to center
5. Run engine and check for leaks.
(neutral) position.
BREAK-IN. On start up apply the load intermittently for a
Whenever the steered wheels are subjected to shock loads,
few seconds et a time, for approximately ten minutes run-
the movement of the steering linkage tends to actuate the
ning time to break in the new parts.
valve in the dreg link momentarily. This action mows the
valve piston axially in the appropriate direction. Thereby
DRAG LINK VALVE (6Z197)
diverting the hydraulic fluid to the proper side of the steer-
DESCRIPTION. The drag link valve is actuated when
ing cylinder piston, end thus resisting the force of the
turning effort is applied to the steering wheel of the vehicle.
shock. This blocking action prevents "kickbacks" et the
The drag link valve directs hydraulic fluid from the pump
steering wheel end stabilizes the steering.
directly to the steering cylinders located in the steering
Very little is required to keep the power steering dreg link
linkage.
valve operating properly. The internal parts are hardened
The valve piston is normally centered by the hydraulic
end ground to a precise finish, end therefore wear of the
pressure against the reaction ring (see Figure 10-13). When
working parts will be negligible under clean operating con-
the operator's effort et the steering wheel exceeds the
ditions. However, foreign matter in the hydraulic system
hydraulic force at the reaction ring, the control valve is
may score the polished surfaces of the piston and body end
actuated end hydraulic power is provided for power steer-
cut the seals. This will eventually result in Ieakage end
reduced power output for steering.
ing.
When the valve piston is in the center (neutral) position, the
DISASSEMBLY. To remove the dreg link proceed es
pressure et the cylinder ports of the valve is low. Under this
follows:
condition them is no circulation of fluid to the steering
cylinders. The fluid is circulating however, from the pump,
1. Disconnect and UP the hvdraulic lines from the valve.
through the valve end to the reservoir.
Note the position in which each line is connected to the
valve so each can be reassembled in the original position.
When the effort in turning the steering wheel of the vehicle
overcomes the centering effect of the force against the re-
2. Remove cotter pin (1, Figure 10-13) and end plug (2).
action rings, the valve piston moves axially to restrict the
3. Remove win lock (3) end socket plug (4). Washer (5).
flow of fluid to one of the cylinder ports. At the same
spring (6), ball seat (7), and bell arm (8) may now be
instant, the passage in the second cylinder port opens, thus
removed. The valve can now be removed from the steering
causing en immediate increase in pressure in one of the
arm of the vehicle. Disconnect the other end of the dreg
ports et the power steering cylinders.
link from the steering arm.
While the fluid under pressure enters one end of the cylin-
4. Hold the valve in a vise for disassembly. CIamp only in
der, fluid from the discharge end of the cylinder returns
the center section of housing (9), since this is the heaviest
through the valve return port to the reservoir.
section.
Full hydraulic pressure is obtained in the steering cylinders
5. Lock ring (10) her been crimped into a notch in the dreg
with a valve piston travel of about 0.035 inch. However, the
link adapter (11). Straighten the ring and remove the
slightest movement of the piston causes a pressure differ-
adapter with a pipe wrench.
ential et the valve cylinder ports. When the effort et the
Figure 10-13. Drag Link Valve (6Z197)
10-14
