Page 500 - Foton Workshop Manual - Auman EST-M

DI - 446 Diagnosis - Mechanical fault diagnosis

Rear suspension assembly fault

Overview

Function of rear suspension:
1. Together with the tyres, absorb and reduce various trembling, swinging, vibrating, etc. to ensure the safety
of passengers and goods so as to improve driving stability.
2. Transfer the driving and braking force produced by the friction between the wheels and ground to the
chassis and body.
3. Support the body on the axle and keep suitable geometrical relationship for the body and wheels It impacts
greatly on the main performance of vehicle, such as driving smoothness, operating stability, fuel economy, etc.
4. Because of rough road, speed change and other reasons during driving, the vehicle will vibrate. The spring
deformation will increase, which will shorten the life of plate spring, body, frame and othe parts In order to
decay the viberation of vehicle to improve driving smoothness, install the absorber The absorber is a
cylinder-type absorber. It is installed in the suspension in parallel with the steel spring to absorb the vibration
of vehicle when the plate spring goes up and down so as to make it recover the stable status rapidly to
improve the stability of vehicle driving.
Precautions

1. Prohibit excessive overload, unbalance loading and uneven force. Otherwise, the camber of plate
spring will reduce and elasticity will become weaker.
2. Prohibit sudden braking, particularly when it is fully loaded. Deal with emergencies in
advance.Otherwise, the front plate spring may be broken due to too much bending force.
3. Prohibit too high speed, particularly when driving on a rough road. It will increase the deformation
range and frequency of plate spring, thus increase the bending force and fatigue.
4. Prohibit sudden turn. When making a sudden turn, the vehicle will produce centrifugal force and
increase the load of outer plate spring. The more sudden the turn, the bigger the load and the more
damage.
5. The plate spring must be maintained regularly. When dismounting for inspection, coat graphite
grease on each leaf to avoid or reduce fatigue, wearing and rusting of plate spring Therefore, need to
perform service regularly to extend the life.
Failure phenomenon list

Failure phenomenon Possible reason Failure elimination
1. Vehicle (overloaded) Follow the rated load
Body sunken
2. Spring (no strength) change
1. Vehicle (overloaded) Follow the rated load
Rear wheel swinging
2. Spring (no strength) change
1. Plate spring broken due to overloaded or
Follow the rated load and adjust the speed
driving at high speed on rough road.
Tighten the U-bolt according to the
2. U-bolt (loosening) specified torque when the spring is pressed
flat
3. Spring pin and bush (over-worn) Repair or replace the worn parts
Plate spring broken or noisy 4. Lack of lubrication between plate springs Relubricate or replace the parts
5. The declination of various plate elasticity is
Check, replace broken leaf or replace the
different or individual plate breaking causes
assembly
the body tilting
6. Leaf spring (broken) or shock absorber
Replace the broken leaf or absorber
(failure)
7. Buffer block (falling off) Replace the bump stop

DI-446