In order to make the frame and body vibration attenuation rapidly, improve the ride comfort and comfort of the car, the car suspension system is generally equipped with shock absorbers, the car is widely used is two-way action cylinder shock absorbers.
The test of shock absorber includes the performance test of shock absorber, the durability test of shock absorber and the double shock test of shock absorber. The indicator test, friction test and temperature characteristic test are carried out for each type of shock absorber.
First, make the car stop after driving 10km on the road with poor road conditions, and touch the shock absorber shell by hand. If it is not hot enough, it indicates that there is no resistance inside the shock absorber and the shock absorber does not work. At this time, appropriate lubricating oil can be added, and then the test is carried out. If the shell is heated, the shock absorber is short of oil, and sufficient oil should be added. Otherwise, the shock absorber fails.
Two, press the bumper hard, and then release, if the car has 2~3 jumps, it indicates that the shock absorber works well.
Three, when the car is moving slowly and the emergency brake, if the car vibration is more severe, it indicates that there is a problem with the shock absorber.
Four, remove the shock absorber upright, and the lower end of the connection ring clamped on the pliers, pull the damping rod several times, at this time there should be stable resistance, pull up (recovery) resistance should be greater than the resistance to the downward pressure, such as unstable resistance or no resistance, may be the shock absorber internal oil or valve parts damaged, should be repaired or replaced parts.
Repair
After determining that the shock absorber has a problem or failure, you should first look at the shock absorber for oil leakage or traces of old oil leakage.
The oil seal washer and seal washer are broken and damaged, and the nut of the cylinder head is loose. It may be that the oil seal and seal gasket are damaged and fail, and a new seal should be replaced. If the oil leakage still cannot be eliminated, the shock absorber should be pulled out. If there is a hair clip or the weight is not right, then further check whether the gap between the piston and the cylinder is too large, whether the piston connecting rod of the shock absorber is bent, and whether the surface of the piston connecting rod and the cylinder is scratched or strained.
If the shock absorber does not leak oil, it should check whether the shock absorber connecting pin, connecting rod, connecting hole, rubber bushing and so on are damaged, unwelded, cracked or shed. If the above checks are normal, the shock absorber should be further decomposed to check whether the fit clearance between piston and cylinder is too large, whether the cylinder is strained, whether the valve seal is good, whether the disc and the seat fit tightly, and whether the stretching spring of the shock absorber is too soft or broken, and repair or replace the parts according to the circumstances.
In addition, the shock absorber will make a noise in the actual use of the fault, this is mainly due to the shock absorber and leaf spring, frame or shaft collision, rubber pad damage or fall off and the shock absorber dust cylinder deformation, insufficient oil and other reasons, should be found out the reason, repair.
The performance test of the shock absorber should be carried out on the special test table after inspection and repair. When the resistance frequency is 100±1mm, the resistance of the stretching stroke and compression stroke should meet the requirements. For example, the maximum resistance of CAl091 stretching stroke is 2156~2646N, and the maximum resistance of compression stroke is 392~588N. The maximum drag of east windmill stretching stroke is 2450~3038N, and the maximum drag of compression stroke is 490~686N.
If there is no test condition, we can also use an empirical practice, that is, to insert an iron rod into the lower end of the shock absorber ring, which indicates that the shock absorber is basically normal.
Post time: Apr-07-2023