SERVICE HINT
Troubles with the power steering system are usually
concerned with hard steering due to the fact that
there is no assist. In such cases, before attempting
to make repairs, it is necessary to determine wheth-
er the trouble lies with the pump or with the gear
housing. To do this, an on±vehicle inspection can be
made by using a pressure gauge.
ON±VEHICLE INSPECTION
Power steering is a hydraulic device and problems
are normally due to insufficient fluid pressure acting
on the piston. This could be caused by either the
pump not producing the specified fluid pressure or
the control valve in the gear housing not functioning
properly so that the proper fluid pressure can not be
obtained.
If the fault lies with the pump, the same symptoms
will generally occur whether the steering wheel is
turned fully to the right or left. On the other hand, if
the fault lies with the control valve, there will gener-
ally be difference between the amount of assist
when the steering wheel is turned to the left and
right, causing harder steering. However, if the piston
seal of the power cylinder is worn, there will be a
loss of fluid pressure whether the steering wheel is
turned to the right or left and the symptoms will be
the same for both.
Before performing an on±vehicle inspection, a
check must first be made to confirm that the power
steering system is completely free of any air. If there
is any air in the system, the volume of this air wilt
change when the fluid pressure raised, causing a
fluctuation in the fluid pressure so that the power
steering will not function properly. To determine if
there is any air in the system, check to see if there
is a change of fluid level in the reservoir tank when
the steering wheel is turned fully to the right or left.
For example, if there is air in the system, it will be
compressed to a smaller volume when the steering
wheel is turned, causing a considerable drop in the
fluid level. If the system is free of air, there will be
very little change in the level even when the fluid
pressure is raised. This is because the fluid, being a
liquid, does not change volume when compressed.
The little change in the fluid level is due to expan-
sion of the hoses between the pump and gear hous-
ing when pressure rises.VANE PUMP
The main component parts of the vane pump,
such as the cam ring, rotor, vanes and flow con-
trol valve are high precision parts and must be
handled carefully. Also, because this pump pro-
duces a very high fluid pressure, O±rings are
used for sealing each part. When reassembling
the pump, always use new 0±rings.
In the flow control valve, there is a relief valve
which controls the maximum pressure of the
pump.
The amount of this maximum pressure is very
important; if it is too low, there will be insufficient
power steering assist and if too high, it will have
an adverse effect on the pressure hoses, oil
seals, etc.
If the maximum pressure is either too high or too
low due to a faulty relief valve, do not disas-
semble or adjust the relief valve, but replace the
flow control valve as an assembly.Also, air in the system will sometimes result in
an abnormal noise occurring from the pump or
gear housing when the steering wheel is fully
turned in either direction.
This on±vehicle inspection must be performed
every time to ensure that the power steering
system is working properly after overhauling or
repairing the pump or gear housing.
± STEERINGPower Steering Description)SR±19
13. INSTALL RACK GUIDE SPRING CAP LOCK NUT
(a) Apply sealant to 2 or 3 threads of the lock nut.
Sealant: Part No. 08833±00080, THREE BOND 1344,
LOCTITE 242 or equivalent
(b) Using SST, install and torque the lock nut.
SST 09612±24014 (09612±10022,09617±24020)
Torque: 570 kg±cm (41 ft±Ib, 56 N±m)
HINT: Use a torque wrench with a fulcrum length of 340
mm (13.39 in.).
(c) Recheck the total preload.
14. INSTALL DUST COVER
15. INSTALL CLAW WASHERS AND RACK ENDS
(a) Install a new claw washer.
(b) Using SST, install and torque the rack ends.
SST 09612±10093 (09628±10020)
09612±24014 (09617±24011)
Torque: 730 kg±cm (53 ft±11b, 72 N±m)
HINT: Use a torque wrench with a fulcrum length of 340
mm (13.39 in.).
(c) Using a brass bar and hammer, stake the claw washer.
16. INSTALL RACK BOOTS, CLAMPS AND CLIPS
(a) Insure that the tube hole is not clogged with grease.
HINT: If the tube hole is clogged, the pressure inside the
boot will change after it is assembled and the steering
wheel turned.
(b) Install the boots.
HINT: be careful not to damage or twist the boots.
(e) Install the clamps.
(d) Install the clips with the ends facing outward.
± STEERINGPower Steering (Gear Housing)SR±62
