I recently purchased a 92 SC400 (w/81,500 miles). A week ago, I noticed that when I turn either left or right, there is a knocking sound.

This knocking is not consistant, nor does it occur all the time.

I have noticed that when the knocking occurs, if I turn either left or right two times in a row, I do not hear the knocking on the second turn. I only hear the knocking twice in a row when I turn in the opposite direction of the first occurance of the knocking (i.e. Turn left, hear knock, turn right hear knock, turn left again, hear knock. If I turn left and hear the knocking, I do not hear it again if I turn left again. Also, I may not hear it again if I turn right after making two lefts.)

My car is currently at the dealer as they have no clue as to what the problem is and are awaiting parts that may, or may not, fix the problem.

So far they have tightened everything down; replaced the bushing and the strut, but noise still occurs.

The car has aftermarket wheels, and the dealer swapped the left front wheel with the right front wheel to see if that would fix the problem, it didn't.

Their next step is to try replacing the lower control arm, if that doesn't work, they are going to try replacing the upper control arm. If that doesn't work, I don't know what they will try next.

Needless to say, I am curious as to what this problem might be and if there is anyone out there who has had the same problem and knows how to fix it

Thanks in advance for any help you might have.

Feel free to e-mail me (rbilbey@earthlink.net) if you wish to ask additional questions, or to offer suggestions.

 

power steering pump could be bad. Common in Lexus's I hear. Ethan's is going bad...that's my only guess.

 

Is this the front or rear!??!

 

It sounds like it is coming from the front end.

Also, I should amend my original statement and describe the noise as a clunking noise rather than a knocking noise.

When I turn the steering wheel, I hear a clunk, then when I turn in the opposite direction, the clunk will sound again. But like I mentioned in the original post, I do not hear the clunk a second time if I turn in the same direction twice in a row.

The noise only occurs while turning. I have never heard the noise while driving in a straight line, nor does the noise repeat itself when it occurs. In other words, when I turn, I hear one clunk, I do not hear the clunk when I straighten out of the turn, only during the turn itself.

Hope this additional info helps.

 

Have they checked the mounting bolts of the steering rack? They do become loose or their rubber bushes get worn out. One symptom is a "wandering" feeling when going straight and hitting road irregularities.

 

I don't know if they have, I was told that they tightened everything (but was not told specifics) and the the clunk still persists.

As it is a holiday weekend, I can't call and ask. They still have the car (gave me a 2001 IS300 to play with ) and will try changing the cotrol arms on Tuesday when they get the parts.

I will of course ask them if they have checked what so far has been suggested.

So keep the suggestions coming, I can't believe I am the only one that has encountered this problem.

There are 2 Lexus dealers in my area and I plan on calling the second one to see if they will give me any information (although I doubt they will when they know it is at a competitors dealership, but it can't hurt to ask).

 

I got my car back from the dealer, and they cant' find the origin of the noise. They have ruled out the mechanics of the vehicle, the suspension and the after market wheels. Their suggest is to take it to a body shop to check for "loose body welds"

They replaced the bushings, the strut, the lower & upper control arms and put on stock wheels.

I have an appt on Monday (Sept 10) at a body shop that the Lexus dealer highly recommends.

When I called the body shop, I was told that they have had a few Lexus' in with loose body welds in the past 5 years (which was mildly relieving), but could not tell me that was my problem without first looking at the vehicle.

Just thought I would keep you posted.

 

I had a car (not a Lexus) that did something very similar. It turned out that the bolt that secured the end of the anti-sway bars needed to be tightened. On this particular car, the bolts went through large rubber bushings which made them hard to inspect.

 

Bingo! Well at least I had this once. My old Fiero had this problem. I added a non-factory anti-swar bar, and I started hearing a clunking when turning, but ONLY when turning opposite directions each time, like you. If I turned left, it would slide all the way that direction and clunk....and not do it again until it slid the other way.

Well being me, I modified the sway-bar mounts to be tighter, and it stopped. If you have factory anti-sway bars, have them make sure the bolts are tights, and replace the rubber mounts that they're in. Then...or before you have them replace those...here's how to find out....

To test and see if it is them...you know what part is the anti-sway bar, right? Well take some white-out and mark the bar at the edges of the rubber mount-holder-thing-a-ma-bobs, but actually on the bar where it goes in them. Ya, those. You'll know what I mean if you're lookking at it. Well go driving, and turn sharp to the left so you hear the clunk. Stop ASAP (without turning sharply) and look at the bar. If the white-out mark has slipped real far into the mount....then it's those bad old hard rubber mounts. If it hasn't....try driving and turning the OTHER way until it clunks. Then check the same.

Luckily mine did it INSTANTLY after putting on the aftermarket bar, so I knew what it was.

Hope this helps!!

SRe