The technical standards for testing the steering system are: the connection parts of the steering mechanism are not loose, and the locking is reliable; the free rotation of the steering wheel is not greater than 15 degrees; the maximum steering angle is 28 degrees, and 40 minutes and the wheels are not rubbed.

The test method for the free rotation amount is: to measure the straightness of the front wheel; turn the steering wheel from one extreme position to the other extreme position (until resistance is felt), and the central angle corresponding to the arc length is the amount of free rotation of the steering wheel.

At the same time, the power steering system can also be divided into the following four major items to check and check the steering control force, the steering wheel return check, the check of the steering oil pump pressure, and the check of the system pressure.

1. Check the steering force

Inspection method: Park the car on a level and dry road, the oil temperature reaches 40~80℃, the tire pressure is normal, and the front wheel is in a straight driving position. When the engine is running at idle speed, the spring balance will be hooked on the edge of the steering wheel, and the steering wheel will be pulled to check the change in the pulling force required for the steering wheel to turn left and right. Generally speaking, if the operating force of the steering wheel exceeds 44.5N, it means that the power steering is not working properly. Check whether the belt is slipping or damaged, the oil pressure or oil volume output by the steering oil pump is lower than the standard, whether air is involved in the oil, and whether the oil pipe is compressed or twisted.

2. Steering wheel return inspection

Inspection method: Observe the following items while driving during inspection:

1) Turn the steering wheel slowly or rapidly, check whether the operating force of the steering wheel is significantly different under the two conditions, and check whether the steering wheel can return to the middle position.

2) Make the car drive at a speed of about 3.5Km/h, turn the steering wheel 90 degrees clockwise or counterclockwise, and then let go of the hand for 1~2 seconds. Find out the cause of the failure and eliminate it.

3. Check the steering oil pump pressure

Inspection method: Connect the pressure gauge and throttle valve with a range of 15Mpa to the pipeline between the steering oil pump and the steering valve, start the engine, and add ATF oil to the oil storage tank if necessary. Start the engine, let the engine idle, and turn the steering wheel several times. Quickly close the throttle valve (no more than 5~10s), and read the pressure number, the rated value should be 6.8~8.2Mpa (Santana 2000). If the pressure is sufficient, it means that the steering oil pump is normal. If the ratings are not met, the pressure and restrictor valves should be checked for integrity.

If it is not normal, you should replace the relief valve, and safety valve, or replace the steering oil pump.

4.Check the system pressure

Inspection method: connect the pressure gauge and throttle valve, turn on the throttle valve, start the engine and run at idle speed, rotate the steering wheel to the left and right to the limit position, and read the pressure on the pressure gauge at the same time, the rated value is 6.8~8.2Mpa. If the left and right ratings do not meet the requirements, repair the steering gear or replace the assembly.

The vehicle steering mechanism is a mechanism used to control the driving direction of various wheeled or tracked vehicles and has an extremely important role in automotive components.