Ninety-Eight V6-3.8L VIN K (1995)
Steering Gear: Description and Operation
POWER STEERING GEAR
The power rack and pinion steering gear has a rotary control valve which directs hydraulic fluid corning from the hydraulic pump to one side or the other
side of the rack piston. The integral rack piston is attached to the rack, and converts hydraulic pressure to a linear force which moves the rack left or
right. The force is transmitted through the inner and outer tie rods to the steering knuckles.
If hydraulic assist is not available, manual control is still possible, but more steering effort is required. Without hydraulic assist, the movement of the
steering wheel is transferred to the pinion. The pinion's movement is then transferred through the pinion teeth, which mesh with teeth on the rack, causing
the rack to move.
TWO FLOW ELECTRONIC SYSTEM
The two flow electronic (TFE) system is a speed-dependent power steering system. The system provides either full power assist, or a preset reduced level
of assist. The CB-series pump utilizes a solenoid equipped fitting in place of the standard union fitting. This solenoid is electrically controlled by on-off
signals from the multi-function chime module, which serves as the "brain" for the TFE system. The module receives speed-related input signals from the
powertrain control module (PCM), decodes them, and signals the TFE solenoid to energize or de-energize.
At vehicle speeds below about 27 to 32 km/h (17 to 20 mph), the solenoid is energized, enabling maximum assist from increased fluid flow through the
system. Full assist via full fluid flow is maintained for about 3 minutes when the vehicle is not moving and the engine is idling. However, after this time
has passed, the solenoid is de-energized and the TFE system shuts down until the vehicle begins to move again. This de-energization reduces
unnecessary heat build up in the solenoid coil.
As the vehicle is accelerating toward 32 km/h (20 mph), the solenoid is energized. Beyond this speed, the solenoid is de-energized again, the fluid flow
returns to its "normal" flow, and the steering effort needed is similar to a standard power steering system.
SEAL REPLACEMENT
Lip seals, which seal rotating shafts, require special treatment. They are used on the steering gear at the pinion shaft and on the pump drive shaft. When
leakage occurs in these areas, always replace the seal after inspecting and thoroughly cleaning the sealing surface. If corrosion in the lip seal contact zone
is slight, dean the surface of the shaft with crocus cloth. Replace the shaft only if very severe pitting is found, such that leakage cannot be stopped by
cleaning the shaft.
