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San75

Unstable when driving over the slightest bump

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I had an issue where the car would shake when braking. I checked the suspension components and found one of the outer ties road has some play so I changed it. The shake was still there so I end up changing all the front suspension apart from the shocks and sway bar bushings that seem ok. The discs were warping when hot. Changed the front discs and the shaking disappeared. Since then the car has been unstable when driving over the slightest bump. Changed the front top mounts and had a 4 wheel Hunters alignment done, still the same.  Any ideas? It’s done 143k, M sport 530d.

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Don't know if a typo but you say Since you have replaced the discs the car wobbles around?

 

It sounds like you have replaced most of the suspension parts that would cause an issue like this.  The shocks ok?

Edited by Enzo503

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Sorry should have said a few weeks after changing the discs a wobble started and gradually got worse. It's not related to brakes or discs. Regarding the sub frame mounts, are we talking about the rear sub frame? I occasionally feel something at the back clunk-ing, it feels like the Guibo disc when changing gears however it only happens once in a while. Could it be that the sub frame is moving about when driving away or changing to higher gears?

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How do you mean unstable? As in the car continues to bounce afterwards, or veers to one side, or feels sensitive to steering/acceleration/braking inputs? 

 

How does it feel round corners, on straight road sections? 

 

If its only over bumps more than likely it is a suspension related problem

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It's perfect on smooth roads. Any slight bump or ditch either on the left or right side of the car it feels like it's floating out of control, like a wobble left to right. The shock absorbers do not keep on bouncing and the steering seems very firm due to new components. I’ve pushed it to 50mph around a bend and that seems to be fine. I’ve taken it to 3 garages and they all say they can't find anything wrong with it. The shocks are fine, can't be the guibo, no play in the rear suspension, tyres ok etc. I drove another E60 same spec that drives like a completely different car. I thought it was the shocks however I compared the bounce to the other car. Mine bounces very similar although it has 30k more on the clock. I’m going to check the sub frame tomorrow.

Edited by San75

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Some things to try:

 

Poor tyre manufacture? Jack up each wheel and give them a spin, take note of the tread pattern whilst rotating. Look for any oscillations (left to right or buckles), I once had a pair that were not formed true and put the car effectively in a constant skid, at speeds +40mph when cornering the handling was very scary and the car easily broke away.

 

Whilst jacked up, stand/push hard on the lower rim, push in toward the car looking for any movement (lower ball joint slop).

 

Plus go to an empty carpark, from a distance Eyeball the wheels and look for any odd alignment or camber angles between the front and rear wheels. Maybe do the same at full lock, you might identify a difference compared to another E60. Could have a 'wrong' parts fitted or a parts fitted incorrectly.

 

Pull off, stop then reverse. Do it a few times then get more agressive, pull off then hard stop then sharp reverse n stop. Try various speed bumps and small curbs (careful if you have lower or M-sport body work).

Open the door, stand next to the car, get hold of the roof and give the whole car a good shuv n shake, try not to damage the kick plates by standing on/off them. Try and see if anything starts knocking/squeaking that could give any more clues to investigate.

You get the idea, might help....

 

Edited by DarkHorse
typo's

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Have you checked the Rose joints on the rear hubs? I've heard these can cause that floaty feeling due them moving it will have an effect on the wheel alignment. 

 

As the front has been overhauled, it sounds like the issue is on the rear of the car. 

Edited by dj1233

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I would agree with Dark Horse.... Did this issue exist before your "new Khumos" were fitted? Think about the only part of your car that touches the road... It would only take one dodgy tyre to affect the whole handling of the car. Do you have access to another set of wheels/tyres?

Edited by Steve-Savalas

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The tyres are at least 6 months old that look like new. I believe the issue has always been there even with the old tyres however it has only got worse after the front suspension was overhauled 2 months ago. I seem to notice the wobble more due to the firmer ride the new parts have provided at the front. I have rocked the hell out of the car, listened to sounds, checked for play in bushes, linkages, driven over bumps in different ways, checked tyres, bearings, brakes, had the wheels balanced etc.

 

The main reason why I overhauled the front suspension was due to shaking when braking. My excessive acceleration and heavy braking were warping the discs when they got hot I later found out. There was no need for me to replace the front suspension parts. I’m going to replace the front sway bar bushing in the next few days and get another 4 wheel alignment done. If this doesn’t cure the issue then I’m going to overhaul the rear suspension and take it front there. Does anyone know if a rear trailing arm bush removal tool will work on the sub frames bushes too?

 

Also i have replaced all the parts myself as i do not trust anyone else working on my car. It’s a job for them, it's a passion for me!

 

Edited by San75

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I had the alloys refurbed when i put on the new tyres. Had them checked out last month when I had them re-balanced. No cracks or serious buckling. I drove the car this morning and drove better than last week. I must be a bushing somewhere that need replacing.

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I replaced the front sway bar bushings, torqued up all the linkages, ties rods and control arms. Made no difference to the stability. As soon as the front end goes over a bump it’s feels like one of the front wheels is turning out of alignment for a split second. Could a worn steering rack cause this?

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You would feel slop in the rack by turning the wheel before the rack moves.

 

What exactly have you replaced in the front suspension?  There is a traction arm, a control arm (these are the two lower arms)  track rod end, track rod (with inner joint), drop link, roll bar bush, shocker, spring and top mount. 

 

I would be tempted to swap your wheels and tyres with that of another E60 to rule out your wheels.

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The best way to check f you have anything loose on your suspension parts is to jack up each corner of the car (not forgetting to place your axle stands)  and first grab the wheel from behind in the 9 and 3 position and pull/push.

If you have any free play, you should be able to tell if its your steering rack or other suspension components.   Now grab the wheel 12 and 6 and push/pull.    Lastly to check your shocks get a long strong bar and place it under the wheel and lift up, there should be no slack in any of these tests.

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Upper and lower control arms, inner and outer track rods, drop links, sway bar bushings and top mounts all have been changed. The springs were ok and the shocks did bounce only once when the wing was pushed down. There is hardly any slack in the wheels at 9-3 and 12-6. I think i will try used the method of jacking up and using strong bar to compare the front shocks. At 143k miles they most likely need changing.

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I jacked up each front wheel and used a long strong bar to lift the wheel on each side to check the shocks. I found one both shocks responded the same. When lowering the trolley jack i found each side would slowly lower until the last few inches where it would drop suddenly. Is this the characteristics of a dual hydraulic fluid and gas filled shock? Two mechanics said while driving the car that the shocks seems ok. I do not want to go out and spend over £400 on new front shocks and then have to overhaul the rear suspension if it does not cure the problem. My 530D 2006 with 143k that is hardly worth £2500 now. Is it about time a changed the car?

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The rear seems to be good. 1-2mm more play than the front. Recently a slight knocking noise has appeared when first moving off or turning the wheel sharply on the front and very low speeds. Feels like it is from the driver’s side shock. Also occasionally the car pulls to one side. 95% of the time the car drives ok. It must be either the shafts that go deep into the front shocks or a faulty steering rack. Would a faulty steering rack cause stability issues when going over bumps? And how would one test the steering rack?

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1 hour ago, San75 said:

The rear seems to be good. 1-2mm more play than the front. Recently a slight knocking noise has appeared when first moving off or turning the wheel sharply on the front and very low speeds. Feels like it is from the driver’s side shock. Also occasionally the car pulls to one side. 95% of the time the car drives ok. It must be either the shafts that go deep into the front shocks or a faulty steering rack. Would a faulty steering rack cause stability issues when going over bumps? And how would one test the steering rack?

 

That knock could be the strut brace bolts..try tightening them.

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14 hours ago, San75 said:

Recently a slight knocking noise has appeared when first moving off or turning the wheel sharply on the front and very low speeds. 

 

Thats the symptoms I got when I had a worn track rod end and lower arms. Soft clonk at low speeds when turning, but you've said you have already replaced them..... The lower arm was obvious to hear knocking when lifting off for coasting.

 

 

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