Rattle Under Car On Bumps

rattle in car over bumpsI am having slight problems with the underside of the car. When I go over bumps on the road or any little thing sticking up it makes quite a cracking noise on both wheels on the left side especially the back left wheel (tires are properly inflated).

Also when I washed my car, I jet washed all of the suspension coils and everywhere behind the wheel and for a little while after when I drove it, for about 1-hour it seemed to be a lot better of a drive (feel less of the road).

What is the reason for this?

When I break the steering wheel wobbles quite badly, usually worse, when I have a passenger in the car. I have got a feeling it might be something to do with the left disk break.

What do you think?

I would be ever so grateful if you could answer my questions.


Kind Regards,


Hi there James,

The first thing that comes to mind on your noise over bumps complaint would be worn out strut mount bearings. The strut mount holds the strut to the body of the vehicle. When the rubber of the mount deteriorates, it allows the strut to come in contact with the body of the vehicle, producing a metal to metal clanging noise when you hit a bump.

There are other rubber insulators on steering and suspension linkages under the vehicle, like sway bar bushings and stabilizer link bushings that can deteriorate and cause the part to come in contact with the underbody of the vehicle.

Since the noise changed or went away after you sprayed the underside with water would tell me that the rubber bushings are probably stick intact, but worn out and the water softened the bushings enough to dampen the noise under the rubber got dry and hard again.

The braking issue you mention is probably due to your brake rotors being warped and needing to be machined smooth again or replaced.

Here is more information on brake rotor warp problems and what to do about it.

Please share this with your friends,
Austin Davis

Posted in: Brakes

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