Vivaro Steering Shake

[GasNob]

Hi all, i have a 53 plate Vauxhall Vivaro 1.9 D engine is running smooth as? fingers crossed.
The problem i am having is the steering wheel shakes from left to right and speeds up the faster i go, when i get to about 60 or over its not noticeable however when i am under this speed its quite vigorous and seems to be getting worse.
A friend said its the front brake discs that have warped but the guy at my local garage checked the brakes and said there is nothing wrong with them? strange for a garage to say this i know. I am sure its not the wheels that need balancing as the push pull is quite severe and is there all the time the van is driven not just at a certain speed.
Another friend said it could be the steering rack? can anyone shed some light on this and tell me how i can tell if the steering rack has failed. or tell me my best options.
Thanks in advance to all who answer.

 

[Burnerman]

As you rightly suggest, steering wheel wobble is due to wheel balance on 95% of all occasions. However, do have the front wheel rims checked for dents due to potholes, and likewise the tyre condition.
If all fails here then you could have driveshaft issues, and they should be checked too.
If the discs were at fault, the wobble would become more severe when the brakes were applied.
The steering rack could have excessive wear, but grabbing the wheels at a quarter to three position and rocking them should show that up.
Presumably the vehicle hasn't recently been involved in an accident?
John

 

[Peter.N.]

I agree with John, you could also have a faulty tyre with ply seperation causing a bulge somewhere. Jack the wheels up just clear of the road and rotate them while watching for run out.

Peter

 

[Mursal]

Throw the back wheels onto the front and see if the problem changes?

 

[GasNob]

As you rightly suggest, steering wheel wobble is due to wheel balance on 95% of all occasions. However, do have the front wheel rims checked for dents due to potholes, and likewise the tyre condition.
If all fails here then you could have driveshaft issues, and they should be checked too.
If the discs were at fault, the wobble would become more severe when the brakes were applied.
The steering rack could have excessive wear, but grabbing the wheels at a quarter to three position and rocking them should show that up.
Presumably the vehicle hasn't recently been involved in an accident?
John

As usual you guys are the real deal! i had the wheels looked at and sure enough the front tyre had blown! i will try to upload a piccy of the faulty tyre so you can all have a good laugh at it! funny but if it had blown im sure i would not be laughing now.

Thanks to you all for the tremendous work and invaluable knowledge.