Troubleshooting car problems of rear suspension that makes thump sound
Let’s analyze first what composes your car rear suspension. A rear suspension is consisting of two major components namely shocks and springs. On most vehicles such as SUV’s or those vehicles that uses a rigid leaf spring for their suspensions these two components are separate from each other. However, on some vehicles they are part of a unit called the “strut”. The portion of the strut with shocks is called the “strut cartridge”. What does it do?
As you may not aware of, the spring is the one that absorbs irregularities of the road and the function of the “strut cartridge” is the one that keeps the spring from bouncing too much or it is the one that restrict the springs contraction and expansion.
When your vehicle passes quickly over a dip, your vehicles entire rear end weight comes down on the rear suspension. If the shocks or the strut cartridge are worn or is faulty it cannot handle the weight of the entire rear end. When this is the case the springs will be compressed to maximum which then be resulted to a loud thump you are hearing.
To confirm if you have a worn or faulty shocks or struts cartridge, try to step down on the rear bumper several times to get it bouncing and let off. If the bouncing continues more than once, the shocks or strut cartridges are worn or faulty.
Possible Cause of Thump Sound on Rear Suspension While Driving on Dip
Faulty or Worn Rear Shocks or Rear Struts Cartridges.
How to Fix Thump Sound on Rear Suspension
(1) Determine what type of rear suspension does your vehicle is having. Does your vehicle rear suspension have shocks or struts?
(2) If your car has shocks, replacing it should correct the problem if not, then the problem is your springs. However, springs are unlikely to cause such problem because usually the life of spring last the life of your vehicle.
(3) If your car has struts, depending on the conditions you have to replace the entire strut or simply have the strut cartridges replaced. But you need to confirm first to your car dealer service department if your car model rear strut cartridges is replaceable.
NOTE: Take care of this problem at once. Why? Because every "thump" that is created there is a certain rear suspension components are becoming more damaged (especially "bushings").