Page 498 - Foton Workshop Manual - Auman EST-M

DI - 444 Diagnosis - Mechanical fault diagnosis

Front suspension assembly fault

Overview
Function of front 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
Transfer the driving and braking force produced by the friction between the wheels and road 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.
Composition of front suspension:
1. Consists of front plate spring and absorber. The first is the main leaf with roll holes at the two ends.
There is bushing inside. It is connected with the frame through a plate pin. In order to reinforce the
strength of roll hole, roll the second leaf into a half roll hole to surround the outside of main roll hoe
and leave a big clearance so as to allow the plate spring slide when it is deformed.
2. Front leaf spring assembly is to firmly fix its center on leaf spring seat of front axle by two U-bolts,
hinge its front spring eye with leaf spring support on frame by spring pin and connect its rear spring
eye with lifting eye by front spring pin. The rear end grasswort is connected to the lug through the front
spring pin of steel plate. The lug is hinged to the plate spring lug support on the frame with the plate
pin, which makes its rear end swing forward and backward. In this way, the plate spring can freely
bounce up and down without breaking.
3. The absorber is hydraulic bidirection telescopic absorber which is connected to the frame and front
axle respectively through the connecting pin, upper and lower supports as well as rubber bushing.
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.
6. The reducer shall be maintained regularly.

DI-444