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Matt
Matt, Mechanical Engineer
Category: UK Car
Satisfied Customers: 20260
Experience:  BEng hons Mech engineering, in auto industry 22 years
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60 mph the car starts to vibrate through the steering wheel..slow down

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i have a 2008 superb 1.9tdi comfort,up to about 50mph the car is ok but after that about 60 mph the car starts to vibrate through the steering wheel and the pedals,the car becomes quite noisy and i have to slow down,it also makes a humming noise,this is my 3rd superb and never had this problem before.
Hello


The vibration could be one of the following

Tyre defect - any cracks or bulges on the side-wall of the tyre (inside and outside) these will throw the tyre out of shape and produce vibration - take a good look over the tyre sidewalls and bear in mind that anything that looks suspect when static will probably be ballooning out and far worse at speed so if any doubt then replace the tyre.

Worn suspension joints - jack the car up so the wheel is off the ground (you’ll need to do this for all 4 corners) and shake the tyre from top to bottom and from side to side (with someone holding the steering wheel on the front) there should be no play in either direction. Any play in 1 direction will usually require a joint to be replaced, if there’s play in both directions then the wheel bearing may be at fault. If theres play only up and down its the strut top mount - to find this one you have to shake the suspension strut it self up and down with the wheel off the ground - so you may need to remove the wheel to check this one.
Now with the car jacked up on that side with the wheel about 2 inches off the ground use a steel bar under the wheel and lever the wheel up and down slightly, you should be able to look at the end of the axle and see if the suspension arm is moving up and down separately to the axle.If so replace the bush

Worn drive shaft joint - typically these won't produce any vibration unless badly damaged but they can be noisy or 'clonk' for a long time beforehand, turn the steering to full lock and look at the drive-shaft rubber boot there should be no rips or tears in it and the suspension should be clean and dry of any grease. If you reverse at a reasonable speed with the steering on full lock a worn joint will 'click'.

Worn mountings - check the tightness of the engine and gearbox mounts and their condition - this is best done by using a jack to take the weight of the engine off the mounts and seeing if any cracks or splits open up in the rubber.Also check the tightness of the mounts bolts

Broken or defective driveshaft vibration damper - some models feature a rubber mass about halfway along the driveshaft - this functions as a vibration damper so 'tuning out' vibration - the rubber needs to be not cracked and the damper firmly fixed to the shaft and running true - anything other than this and the entire shaft will have to be replaced as they are bonded in place
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