Automotive Steering System Fault Diagnosis and Troubleshooting

• • A shift heavy judgments and exclusion

Symptoms:
(1) when the car turns driving, turning the steering wheel is very difficult
(2) The vehicle steering, the steering wheel does not automatically return to position
1, check if the car is overloaded or the front loading too much on the front tire pressure is too low, if the tire pressure is low, should be inflated to reach the specified value.
2, strut front axle, hand turn the steering wheel test. ① If the steering wheel feels light, indicating front axle or the frame deformation, front wheel alignment inaccurate and so on, should check the calibration; ② If the steering still feels heavy, and note down on the steering gear or the steering transmission machinery, has nothing to do with the front axle and axle .
3, removed the steering arm, turning the steering wheel test. ① If the steering feels light, indicating failure in the steering linkage; hand sliding the front wheel about testing, check the steering knuckle kingpin co-ordination with the bush, if I flip the wheel more laborious, indicating steering knuckle kingpin poor lubrication or in combination gap is too small, should bear grease or adjust to meet the gap; ② check the steering knuckle thrust bearing, if the bearing short of oil or damaged should be replaced; ③ check the steering rod of the ball head of the lubrication and tightness, and if TIE ROD END too tight, should bear grease or adjust the ball head tightness, if the steering is still heavy, indicating failure in the steering gear; should be examined within the steering gear lubricant oil quantity and quality if the surface is too low, indicating steering in the lack of lubricating oil, should be added to the required position, if oil deterioration, should be replaced lubricants; Check steering free trip, if the free path is too small, indicating rotation pair steering gear meshing clearance is too small, should be adjusted; turning the steering wheel, checking to listen to steering shaft and casing a married grazing sound, if grazing sound, indicating steering shaft or casing deformation, should be straightening; ④ check the steering shaft universal joints, universal joints, if the oil tank should be filling lubrication fat, if the universal joint cross shaft bearing is damaged, should be replaced; ⑤ Check the upper and lower steering worm bearing preload degree, if the preload through the large, should be adjusted; ⑥ Following the above examinations are normal, should be demolished seized steering, check Steering internal bearings, bushings, gear teeth are damaged or serious vice wear, according to examine the situation, replacing the corresponding parts.

• • Judgments and elimination of low-speed Rocker
  Failure phenomenon: low speed when the car feel unstable direction, resulting in front wheel shimmy
  1, visual inspection
  Check whether the loading of goods vehicles long, which leads to front wheel bearing is too small, checks whether the tire pressure is too low, should be inflated so as to achieve the specified value, check whether the front suspension spring dislocation, split-off or fixed bad, if the dislocation, repair should be demolished; if broken should be replaced, if the fixed-poor, should be required tightening torque.
  2, check the steering wheel free travel
  Hold the steering arm by one person, and the other turning the steering wheel tests, if the free path is too large, indicating clearances steering gear transmission is too large, should be adjusted. Release steering arm, still a man turning the steering wheel, under the observation of another person in the car steering rod ball pin, if Songkuang the phenomenon, indicating the ball bowls ball pin or wear off very, spring break or adjust too loose, you should replace the the damaged parts, and then adjust.
  3. to investigate the above checks are normal, can be supported from front axle, and his hand along the front steering knuckle axis axial sliding the feel to determine whether Songkuang, if Songkuang feeling, may be another person to observe the front axle and the steering knuckle joints, If here Songkuang, indicating steering knuckle kingpin and co-ordination of bush clearance is too large or the front axle kingpin and the kingpin with the clearance hole is too large, should be the main reason for sales and bush. If here is not Songkuang, indicating Songkuang front wheel hub bearings should be re-adjust the bearing preload degrees.
  4, unless such a cause, should inspect front axle and check front wheel alignment is correct, if correct, should be adjusted, check the front axle is deformed, if distortion should be corrected.
• • High-speed Rocker Diagnosis and Removal
  Failure phenomenon: a car at high speed or a higher speed driving, the steering wheel out the rationale shivering, driving instability.
  1, visual inspection
  After checking tire pressure is too low, if the pressure is too low, should be inflated so as to achieve the specified value. Check front axle, steering gear and steering linkage is loose, if loose, should be fastened. Check whether the oil spill before the shock absorber, if the leak or failure, should be replaced. Check from time to time about suspension spring break or stretch weakened, break or stretch if weakened, should be replaced. Check the suspension spring is fixed and reliable, if loose, should be fastened.
  2, branch starting from the bridge, with tripods plugged the non-driving wheel, start the engine and gradually so that the vehicle is shifted into high gear, so driving wheel shimmy speed up the body, if the jitter occurs at this time the body and the steering wheel, indicating shaft severe bending or Song Kuang, drive axle gear mesh gap is too large, should be replaced or adjusted, if the body and the steering wheel does not shake at this time, indicating failure in the former bridge.
  3, check the front wheel from time to time deflection
  Strut front axle, in the front wheel rim had put a draw on the needle, slowly turning the wheel to see whether the wheel rim deflection is too large, if the rim deflection is too large, should be replaced. Remove the front wheel, the wheel balancing instrument in the check, front wheel balancing, and if not unbalance should be balanced to install a balanced blocks.
  4, after the above-mentioned examinations are normal, should check the frame and the front is normal, check the front wheel with front-wheel positioning system is correct, if correct, should be adjusted to check whether the deformation of the frame, if deformation, should be corrected.
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• • Driving wandering Diagnosis and Removal
  Failure phenomenon: car driving straight, we must seize the steering wheel. If slightly loose steering wheel, it will automatically run to the side.
  1, visual inspection
  Check the left and right front tire pressure is consistent, if not, should be required to inflate so that the two front wheels ensure consistent tire pressure, check the left and right front tire wear, if wear and tear inconsistent serious wear and tear should be replaced tires. Check the left and right front tire of the two patterns are the same, such as the patterns are inconsistent and should replace the tires, so that the same pattern. The car parked in a flat on the ground to view the front of the vehicle a high degree of consistency, if a high degree of inconsistency, the vehicle left tilt, indicating suspension spring break or stretch weakened, should be replaced.
  2, hand-to-deviation side of the wheel hub and wheel bearings brake parts, feel the temperature, if I feel particularly hot wheel brake hub, indicating wheel brake clearance is too small or to return to one was not complete, should check the adjustment. If the wheel feels especially hot, stating that the wheel bearings too tight, it should focus on pro-adjusting bearing preload degrees.
  3, measured before and after the bridge at both ends of center distance is about equal, if not equal, indicating the side of a short wheelbase misplaced leaf springs, axles, or axle casing to switch songs, etc. should check the repair. Check with the front-wheel front-wheel positioning locator is correct, if correct, should be adjusted.
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• • Unilateral understeer Diagnosis and Removal
  Failure phenomenon: when the car turned around, there a certain side of the steering angle is too small
  1, visual inspection
  Check whether the shift rod distortion, if distortion, should be straightening. Check whether the suspension spring deformation, whether or broken leaf spring center bolt, if deformed or broken, should be replaced. Check whether the deformation front axle, if deformation, should the school directly.
  2, if the vehicle after the repair of unilateral understeer
  The car parked on flat ground, teams from the former bridge, will turn the steering wheel side in the end, then turn on the other side in the end, remember that turning the steering wheel of the total number of laps, the steering wheel turned by the side of the half of the total number of laps, Check front wheel is in a straight line driving position, if the position of front-wheel drive is not in a straight line indicating the installation location does not move arm should be removed to re-install, if the steering wheel to switch less than half of the total number of laps, the steering angle limit screws on the withstand the steering knuckle, steering angle limit screw adjustment instructions properly, should be redirected.
  2, after the above-mentioned examinations are normal, should be demolished seized steering, check whether there are foreign bodies stuck inside the steering gear, steering gear transmission wear off or even deformation deputy, check to examine the situation, replacing the corresponding parts.
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• • Power steering system steering heavy judgments and exclusion
  Failure phenomenon: when driving vehicle cornering, steering feel heavy, hydraulic power loss of the role of a short-lived
  1, check the steering pump-driven part of the situation in hand steering pump drive belt depressed, if depressed excessive, indicating tight belt drive to persuade to be adjusted. Starting the engine, so the engine running at idle speed, a sudden increase in engine speed, check whether the steering pump drive belt slipping phenomenon, if slipping phenomenon, shows drive belt too loose or too worn or rather, should be adjusted or replaced.
  2, check the steering fluid in the fluid level in the tank, if the steering fluid surface in the winding, or "MIN" line, indicating lack of steering fluid should be added to the provisions of positions.
  3, check the steering fluid filter inside the tank, remove the filter to observe the status of filters, if it had dirty filter, indicating blocking filter should be cleaned. If it is found broken filter should be replaced.
  4, check whether the system will be the air, start the engine and make it run at idle, and then back and forth turning the steering wheel several times to observe the status of steering fluid, steering fluid, if found to have foam or oil turbidity, indicating turn the system with air mixed in, should be dismissed. Check the steering pump inlet pipe is broken, if broken should be replaced. To check whether the pipe joints loose, if loose, should be fastened. Check the steering pump shaft seal ring for damage, if the oil spill should be replaced.
  5, check the hydraulic steering system with a pressure gauge connected to the shift between the pump and power steering devices, so that the engine running at idle, close gauge valve, if the 10S internal pressure reach a fixed value, indicating lack of steering pump pressure should be demolished inspection maintenance. The steering wheel to the left or right limit position, open the gauge valve, if the pressure less than the required value, indicating power steering device has fault or inappropriate valve adjustment should be adjusted off inspection.
  6, check when the engine idling speed, start the engine and make it run at idle, observe the instructions of the table at this time the value of engine speed, if the indicated value is low, or speed instability, indicating the engine idle speed is too low, should be adjusted.
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• • Power steering system and elimination of noise to determine
  Failure phenomenon: when the vehicle steering, steering pumps at the sound generated
  1, check the oil tank inside the steering fluid level, if below the surface off the assembly line, or "MIN" line, indicating steering fluid liquid level is too low, should be added to the required location. If the consumption of fast steering fluid, indicating a serious oil spill Department, should be checked to exclude.
  2, check the steering pump-driven part of the situation, men turned to pressure oil pump drive belt, if depressed too large, indicating too loose drive belt should be adjusted.
  3, check whether there are air-hydraulic steering, open the tank lid, start the engine and make it run at idle, back and forth turning the steering wheel several times to observe whether there are bubbles steering fluid, if air bubbles, indicating steering fluid the mix of air, should be dismissed.
  4, check whether the oil tank filter plugging, pipeline road layout is correct, remove the oil filter tube, such as found dirty, indicating poor oil circulation should be cleaned, if the pipeline road bending, concave deflated, to be replaced .
  5, after the above checks are correct, should be demolished seized steering pump, check whether there are scratches leaf, check whether there are scratches pump, according to the situation were opened to replace the corresponding parts.