The steering column shaft is attached to the gear pinion. The rotation of the pinion moves the gear rack from side-to-side. This lateral action of the rack pushes and pulls the tie rods (4) to change the direction of the front wheels. Power assist is provided by an engine mounted hydraulic pump which supplies hydraulic fluid pressure to the steering gear (6).
Power steering systems consist of:
• Steering column
• Rack and pinion steering gear
• Belt driven hydraulic steering pump
• Pump pressure and return hoses
• Oil Cooler
POWER STEERING SYSTEM
Dodge Ram Truck Service Manual Steering There is some noise in all power steering systems. One of the most common is a hissing sound evident at a standstill parking. Or when the steering wheel is at the end of it’s travel. Hiss is a high frequency noise similar to that of a water tap being closed slowly. The noise is present in all valves that have a high velocity fluid passing through an orifice. There is no relationship between this noise and steering performance.
POWER STEERING FLOW AND PRESSURE
The following procedure is used to test the operation of the power steering system on the vehicle. This test will provide the gallons per minute (GPM) or flow rate of the power steering pump along with the maximum relief pressure. Perform test any time a power steering system problem is present. This test will determine if the power steering pump or power steering gear is not functioning properly. The following pressure and flow test is performed using Power Steering Analyzer Tool kit 6815 and Adapter Kit 6893.
FLOW AND PRESSURE TEST
- Check the power steering belt to ensure it is in good condition and adjusted properly.
- Connect pressure gauge hose from the Power Steering Analyzer to adapter 6826.
- Connect tube 6825A to Power Steering Analyzer test valve end.
- Disconnect the high pressure hose from the power steering pump.
- Connect the tube 6825A to the pump fitting.
- Connect the power steering hose from the steering gear to the adapter 6826.
- Open the test valve completely.
- Start engine and let idle long enough to circulate power steering fluid through flow/pressure test gauge and to get air out of the fluid. Then shut off engine.
- Check fluid level, add fluid as necessary. Start engine again and let idle.
- Gauge should read below 862 kPa (125 psi), if above, inspect the hoses for restrictions and repair as necessary. The initial pressure reading should be in the range of 345-552 kPa (50-80 psi).
- Increase the engine speed to 1500 RPM and read the flow meter. If the flow rate (GPM) is below specification, (refer to pump specification chart for GPM) the pump should be replaced.
If the vehicle is involved in a front end collision/the air bag has deployed the column must be inspected. This inspection will determine if the Column has collapsed. Inspect the column mounting capsules visually and manually push and pull them to check for separation or fractures. If capsules are fractured or have moved the column MUST be replaced.
Vehicles equipped with an automatic transmission and a steering column mounted shifter: an interlock device is located within the shift cable. This interlock device is used to lock the transmission shifter in the PARK position when the key cylinder is in any position and the brake pedal is not depressed.
TEST AND REPAIR
If the key removal effort is excessive on a vehicle with a automatic transmission first adjust the shift linkage, (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 46RE/GEAR SHIFT CABLE - ADJUSTMENTS). If the ignition switch effort is excessive remove the ignition key cylinder from the steering column. (Refer to 19 - STEERING/COLUMN/LOCK CYLINDER HOUSING - REMOVAL). Check the turning effort of the key cylinder. If the ignition key cylinder effort is excessive replace the key cylinder.
The tilt and standard column (4) have been designed to be serviced as an assembly; without wiring, switches, shrouds, steering wheel, etc. Most steering column components can be serviced without removing the steering column from the vehicle. Safety goggles should be worn at all times when working on steering columns.
KEY-IN IGNITION SWITCH
The key-in ignition switch is integral to the ignition switch, which is mounted on the left side of the steering column. It closes a path to ground for the Central Timer Module (CTM) when the ignition key is inserted in the ignition key cylinder and the driver door ajar switch is closed (driver door is open). The key-in ignition switch opens the ground path when the key is removed from the ignition key cylinder. The ground path is also opened when the driver door ajar switch is open (driver door is closed). The key-in ignition switch cannot be repaired and, if faulty or damaged, the entire ignition switch must be replaced, (Refer to 19 - STEERING/COLUMN/IGNITION SWITCH - REMOVAL).
GEAR - LINK/COIL
The gear acts as a rolling thread between the worm shaft and rack piston. The worm shaft is supported by a thrust bearing at the lower end and a bearing assembly at the upper end. When the worm shaft is turned from input from the steering column the rack piston moves. The rack piston teeth mesh with the pitman shaft. Turning the worm shaft, turns the pitman shaft, which turns the steering linkage.