Steering Vibration At High Speed

[Maroon400]

HELP!!!

I'm trying to get to the bottom of this before speeding any money,

I get a slight vibration through the steering wheel when travelling at high speed,

Which seems to extend to the whole car above 90mph, this vibration increases dramatically when braking.

I have had all the 4 wheels balanced at 2 different companies, the tracking has been done with the latest laser system, the tyres have been rotated and the suspension, track rods, wheel bearings etc

have all been checked on one of those MOT testing machines that shake the whole car to find any play.

Also the car has been put on a brake testing roller to see if the discs are warped.

NOTHING!!

Know one can find anything wrong with the car, yet the vibration is still there?

The only advise I've had is "wait for it to get worse mate"

Can anyone shed any light on this ?

[Malc]

Don't know if this helps: ................ long time ago we had an Alfa and the tyres, under heavy driving pressure, went oval and caused mayhem driving but seemed ok at lower speeds !

Malc

[bookend]

Might be worth trying to fing a fellow member to swap wheels to see if the problem is wheels or somthing on the car

[Maroon400]

Swapping wheels sounds like a great idea!

Anyone live in the Kent area? Or Wimbledon SW19

[ambermarine]

Hi Gary

Get all the bushings checked on the rear suspension properly a shaking machine will not find wear in the hubside bushes that is the cause of vibration .It is a common fault on ls400s after 100k and can be difficult to determine .The hubside lower arm bushing is usually the main suspect but the upper arm bushings( there are three in a triangle) wishbone are also prone to vibrating when worn but because of the shape of the set up difficult to see wear until they're off the car.The way to check the hubside lower arm (comes from the subframe at the side of the differential) is to jack the car up and see if there is any play in the wheel from 9 o clock to 3 o clock and 6 to 12 make sure the rear wheels are both off the ground.The other suspect is the trailling arm bushing again this is checked at the hub connection the arm comes from just next to the front of the wheel arch see if it will twist by hand , it should not do.

[Pompeypops]

Mine done the same , Changed bottom ball joint which had wear in it all ok now

[Titch LS]

Gary, my LS has exactly the same symptoms as yours when travelling at 90+ mph. I suspected it might be the prop shaft slightly out of balance but it seems that replacing the bottom ball joints cured the problem for Paul, so that may well be the answer.

[mikeyv]

You can try swapping your own wheels front to back, to see if the vibration alters in any way.

Obviously, if it does, then try swapping the spare one wheel at a time, until you find the guilty wheel.

My first thought was propshaft or a dodgy wheel/tyre, but the posts from those who have cured it by replacing ball joints would seem to point in that direction.

[ManicMark]

I had a similar problem to this on my old ls400 it turned out to be a dry joint on one of the drive shafts repacked with high temp grease & the problem went. It could also be the rear trailing arm bushes that go into the rear hubs, they can cause a vibration at higher speed .

[Maroon400]

Thanks so much for all your suggestions guys

What's the best way to check the front bottom ball joints?

The MOT shaker machine I tried is obviously insufficient and now have the info

To check the rear joints. When I had the wheels off to rotate the tyres

I noticed the rubber gators on the track rod ball joints had just started to crack

That might be an indication that some wear maybe present.

What do you think?

[ambermarine]

There seems to be some confusion setting in about bottom ball joints and bushes The only ball joint on the rear suspension is in the wishbone and that is not usually the main cause of vibration at higher speeds .the problem of vibration affecting the steering is because this is a rear wheel drive and any wear in the suspension at the rear is transmitted through the chassis and emits through the weakest point and that is the steering the complex bushing arrangement at the rear is easily thrown out of alignment when one or more bushings are not doing their job and this too will start to vibrate as the teletrimy of the car is affected and its relationship with the road surface affects weak loading points.

Try to focus on one area at a time when solving a problem otherwise the initial problem starts to become clouded in maybe's.Front suspension issues on this car are usually confined to the upper control arm and that is not the same symptoms we are discussing. The bottom ball joints will throw up other symptoms before vibration if worn too that extent and will be picked up as an advisory at the Mot.There are a stream of examples in the forum archives of this particular issue that is one of the known faults on the LS400.

[Parrot of Doom]

You might try checking the tyres under pressure. Most tyre fitters take the wheels off the car to balance them, but a tyre with a physical defect only apparent when weight is applied would pass any such tests.

http://www.balancemycar.co.uk/

Tyres are always the first port of call, however, as this vibration is through the steering wheel, it should be simple to isolate. Does the front make any clunking/creaking noises while driving? For instance, I recently replaced both the front strut bars on mine and a minor vibration which I thought was a "warped" disc disappeared.

[Maroon400]

Parrot, no noises at the front, also swapped tyres round and spare, still no change.

When you say front strut bars, is that track rods? Please clarify, this could be my problem.

[Parrot of Doom]

Strut bars are the big hunk of slightly curved metal that go from the bottom front ball joint to the chassis. Two bolts on the ball joint, one huge bushing on the chassis. But if you're not experiencing any knocks then I doubt that's the problem.

I would still be looking at tyres and related components, it's almost always the cause.

[Maroon400]

As it happens I will be due for a couple of front tyres in the next few months so will get that done and take things from there.

I think your right, it is the most obvious cause, get that out of the way and see how it goes.