Part 1. Preparation and safety
Objective
- Check front and rear suspension components and measure their wear.
Personal safety
Whenever you perform a task in the workshop you must use personal protective clothing and equipment that is appropriate for the task and which conforms to your local safety regulations and policies. Among other items, this may include:
- Work clothing - such as coveralls and steel-capped footwear
- Eye protection - such as safety glasses and face masks
- Ear protection - such as earmuffs and earplugs
- Hand protection – such as rubber gloves and barrier cream
- Respiratory equipment – such as face masks and valved respirators
If you are not certain what is appropriate or required, ask your supervisor.
Safety check
- Make sure that you understand and observe all legislative and personal safety procedures when carrying out the following tasks. If you are unsure of what these are, ask your supervisor.
Points to note
- The components of the vehicles suspension system are designed to operate as a whole unit. Some vehicles use very sophisticated systems, while others use very simple systems. That means that there may be components on one vehicle that are not found on others, or the materials they are made from differ. Generally, more sophisticated systems contain more components made from more exotic materials.
- The term 'bushing', used in this topic as a component name, may be more familiar to you as 'bush' or bushes'.
Part 2: Step-by-step instruction
- Check coil spring
Remove the tire and wheel assembly to gain better working access. Check the coils for any signs of cracks or fatigue, such as any nicks or scores on any of the coils. Also check the insulating block between the top of the spring and the vehicle body for signs of splitting and chaffing. Any deterioration should be reported.
- Check McPherson strut upper mounting point
Check the upper mounting point of the McPherson strut for tightness. Ensure the spring insulator is in position. With the vehicle on the ground, ask an assistant to turn the steering wheel from lock to lock. Place your hand on the top of the strut mounting as it is turning, and note any noise or feeling of roughness from the top bearing
- Check leaf spring
Check to see if there are any leaves of the spring that are cracked or broken. Also if the spring has noise deadening inserts between the leaves, make sure they are in place. Check the security of the spring center bolt and that the “U” bolts are tight. At the ends of the spring “eyes” are used to locate the springs in position. Check the condition of the bushes or mountings and spring shackles. You can check these by putting a lever in between them and levering against the spring.
- Check the suspension to body mountings
Inspect the bushes or rubber mountings for any signs of deterioration, swelling or crushing. Check the tightness of the bolts. Report any loose mounting bolts or retainers to your supervisor. These joints can also be a source of body noise that can be difficult to diagnose.
- Check vehicle height
Replace the wheels and lower the vehicle. Check that the tire air pressures are correct, and then measure from the bottom of each wheel rim to the center of each wheel arch or opening. Record your readings. After you have completed measuring both sides and front to rear, compare the readings to the manufacturers specifications. If there are any differences in height, you will need to consult the shop manual for the allowable tolerances. Any major differences in the readings could indicate that the suspension springs are worn and have sagged. Report the findings to your supervisor.
Source: CDX Global
