willcrets

My '96 LS400 has a lot of noise from the front end on street bumps and on expansion joints of concrete roadway. When the car hits a dip and then back up, there is a "slap" on the floorboards. From reading the posts I felt the problem must be the front ball joints. My neighborhood mechanic refused to replace them saying that his examination revealed no problem with the ball joints. So I still have a lot of noise in the cockpit. Can the health of the ball joints be determined by only examining the ball? Advice welcome!

StevieA

It took my Uncle and I quite a while to determine for sure the knocking noise through the floorboards was the ball joint. We went for multiple rides with his "mechanical stethescope" attached to many different front end parts until we clipped right to the ball joint then we heard it. The only way we could determine play in the ball joint while mounted was removing the wheel and using a crow bar to pry the ball joint up & down from of it's socket. Then it was OBVIOUS. But other tests for play (side to side etc.) did not reveal it was worn. I can't explain them all because it's from memory but my Uncle has been a mechanic since the mid 1960's and his specialty was front end alignments.

We replaced the upper control arms with a set off Ebay and the ride improvement was significant and the knock was gone.

However note that my noise would happen when running over small "pebbly" gravel like on a dirt road - not large bumps like speed bumps so your problem may be different.

PureDrifter

iTrader: (10)

more likely to be strut rod bushings or control arm bushings if there's not any visible play in either upper or lower ball joints. also make sure the subframe bolts are tight.

willcrets

I had the lower ball joints replaced ($184 parts, $195 labor). After removal, it was determined there was a lot of play but my slapping problem on dips is not remedied. Maybe front struts are bad???

JimsGX

Do you hear it on both sides, one side, middle?

bdshomes

I have a 95 LS that just developed a rattling/knocking sound coming from the right front end while driving down the road. The slighted of unevenness or small bumps in the road will cause the sound to happen. It sounds like something is loose like a break calipure so I took it to an alignment/front end shop this afternoon and they seem to think it could be either a busted strut rod mount or one of the front end bushings. They put it on the rack and spent about 20 minutes inspecting different parts and moving them around with a long pry bar.

Has anyone ever had a strut mount break?

billydpowe

iTrader: (1)

if it was mine, I would replace the strut rod bushings......

bdshomes

thanks for your input Billy, i will definitely look into that. It almost sounds like a front spring is broken and the two parts are now rattling against each other..i read on another Lexus forum that scenario can be one of the possible issues to trouble shoot with the noise issue going on.
I also read in that thread that one guy replaced every single bushing on his front end trying to solve his problem and finally discovered the noise was coming from a broken strut mount. My mounts from the outside appear to be fine,but not sure whats going on underneath the mount.

willcrets

Yes, I hear it from both sides...maybe worse on left side. Noise from ribs across a concrete road seems to feed directly into the cabin. I wonder if the Lexus dealer could diagnose the problem? Replacement of the lower ball joints did not help.

etex

As has been said, replace the strut rods.