Lexs400

1990 LS400.
The rear wheels give away at the slightest dip or uneven surface. wheel hopping would be the right term.
I thought the air suspension was bad so I've had all 4 struts replaced. No change.
I then had all four upper control arms changed based upon the indie's recommendation. still no effect.
I've searched and searched. no results came up.
The traction light comes up every time there's even a small stone under the rear tires.
If i go over a speed breaker or uneven surface the rear makes a loud noise as if there are no struts in the back at all, and the whole rear shakes.
Can anyone make any recommendations ?
Also, on highway at high speed the rear sways like a ship when I change lanes.
thanks a million in advance. Just would like to know what bushings etc could be the reason for this as everything is intact I've had it checked by two shops already. Alignment is perfect too.
1990 LS400 air suspesion about 160K miles. Orig owner. Thought this info could help.

PK_Celsior

iTrader: (18)

the only way to really get rid of the sway is to upgrade to coilovers. thats what i did, and i changed out all my bushings too.

Lexs400

well it's not the normal sway. plus I have air suspension. There's something that's lose that I'm trying to fix to put it back to the stock way it was a month ago.
thanks for the suggestion though

GSteg

iTrader: (15)

Check your sway bar and sway bar endlinks yet?

VVT-i

Check your rear knuckle bushing where the rear trailing arm attached. Those thing worn out after 10 years or so. The part for the bushing is around $80.00 for both sides and a couple of hour to install. If you look under your rear suspension and see all the links/control arms that attached to the knuckle, it's the lowest one/closest to the ground.

damon

Meant to get back to this & VVTI beat me to it.

LS 400 part # for the knuckle/spindle is #42305-50010 (drivers side rear, 94LS). The referred to bushing arrives already installed in this part.

I damaged mine & upon taking it out saw that the bushing had been torn.

I looked into bushing replacement & could not find the part to which VVT-I
is referring. I do know that it takes a special tool to remove.

khooper

Very common problem. Also known as axle wrap.
Easy cure - install the RAS .
You may ask what is the connection the i would say that when the shaft on the end is not fixed. Articulation is unchanged.
The RAS web site does a pretty good job of explaining everything.

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CHECK OUT: ONE FOR THE ROAD

Lexs400

thanks everyone for the reply. would this cause the traction light to constantly come on even at the slightest up or down in the road surface ? and would it cause a loud thump from the rear suspension as if the differential is sitting on bricks when i go over a pot hole etc ?

boosted1

wheel bearings.. check them