Knocking Sound On Right Front Of Car

[LS400inCA]

I just took my 1996LS400 to a mechanic to fix a knocking sound that I hear in the front right of the car when I go over a speed bump or a dip in the road.

He replaced the front strut rods and bushings, but the noise is still there.

Any suggestions as to what the problem might be?

[steve2006]

Sounds like a completely misdiagnosed problem by your mechanic?

Main causes are upper wishbone bushes,upper ball joint,lower ball joint and anti rollbar/tie bar bushes.

Check the wheel bearing.

Also check if the noise goes away when you gently apply the brakes as the pads have been known to rattle.

[IS400]

I just took my 1996LS400 to a mechanic to fix a knocking sound that I hear in the front right of the car when I go over a speed bump or a dip in the road.

He replaced the front strut rods and bushings, but the noise is still there.

Any suggestions as to what the problem might be?

The problem is most likely the upper control arm. It is a large part that is shaped like a wishbone and attaches in two places to the frame/unibody of the car. The best way to see it is to jack up the front of the car and look over the top of the tire and find the control arm as the largest part in there.

It attaches in two places and those bushings on those two points wear out quickly on these cars. Lexus can replace them for a pretty penny or you can get replacement arms and do it yourself.

The bushings are available seperately but are a major job to replace from what I read.

I replaced mine with pieces from arnott industries in florida. They were perfect when first installed but after a little while I notice the noise is back on occasion. A lot better than they were before at least.

I agree about the pads clacking sometimes, so make sure you get your little springs that go on the pads put back on properly to keep them located, each time someone does a brake job for you.

Hope this helps! B)

[LS400inCA]

Sounds like an expensive repair. Any idea as to whether it is an issue I should take care of immediately to avoid even more expensive repairs down the road? I've put $1600 into it in the last month and would love to wait on any more major repairs if I can, but I know it doesn't make sense to wait if it will only cost me more in the long run.

Your input is really appreciated!

[IS400]

Sounds like an expensive repair. Any idea as to whether it is an issue I should take care of immediately to avoid even more expensive repairs down the road? I've put $1600 into it in the last month and would love to wait on any more major repairs if I can, but I know it doesn't make sense to wait if it will only cost me more in the long run.

Your input is really appreciated!

I tried to find inexpensive fixes and they just do not exist in my opinion. The upper control arm is a beefy unit for a reason. There are tremendous loads on those bushings and they tear apart due to those loads. I had to bite the bullet and get replacements and that is my suggestion. Sorry! :(