Body wobble/vibration under acceleration

[Nick Warwick]

Looks like i may have found the problem! my passenger side front wheel bearing has some play in it. This explains why at speed it seems to even back out, strange how i have no usual bearing noises you would associate with a bad bearing!

How easy are the bearing to replace on these cars? they look like a hydraulic press will be needed.

Thanks
Nick

[AngryScot]

I'd be interested to know about replacing the front bearing/hub assembly as well, I've seen a few people say it needs a special tool from Volvo to press the bearing out and my Haynes manual seems to suggest it is not possible but others seem to have managed it just fine.

[Yobbo]

Originally Posted by Nick Warwick

Looks like i may have found the problem! my passenger side front wheel bearing has some play in it. This explains why at speed it seems to even back out, strange how i have no usual bearing noises you would associate with a bad bearing!

How easy are the bearing to replace on these cars? they look like a hydraulic press will be needed.

Thanks
Nick

By all accounts it's easier to change the entire hub out rather than just the bearing!

[Nick Warwick]

Just to keep this updated as it can be annoying for others with similar issues not finding out the final fix.

I have replaced the wheel bearing (pretty easy job) and also replaced my top mount and bearing. This hasn't solved the low end wobble but it has made a slight difference.

Moving forward ill be taking it for the wheels to be checked over.

[Proghound]

Wheels was what my wobble under acceleration turned out to be.

[Proghound]

Originally Posted by Proghound

Wheels was what my wobble under acceleration turned out to be.

... Or so I thought.

For some reason the heavy body wobble under acceleration went as soon as I changed onto the summer wheels. But two weeks later, I noticed it coming back when giving it the beans. This has now been resolved by replacing the OS driveshaft, the central support bearing was on its way out.

I'm now in the midst of sorting out a residual constant vibration. It seems all four wheels had been incorrectly balanced (weights on the rim centre line only), the rear tracking was out (now corrected), and the front was and is still out, because the track rod end adjuster locknuts have seized solid!

It's already much better, I'll report back next week once the front is sorted if it doesn't cure the remaining jitters.

[Yobbo]

Originally Posted by Nick Warwick

Just to keep this updated as it can be annoying for others with similar issues not finding out the final fix.

I have replaced the wheel bearing (pretty easy job) and also replaced my top mount and bearing. This hasn't solved the low end wobble but it has made a slight difference.

Moving forward ill be taking it for the wheels to be checked over.

Nick, don’t know if you still post on here’s or not but I’m having this exact issue right now and it’s driving me mad. Did you get to the bottom of this?

Recently I’ve changed both driveshafts but the replacement longer O/S shaft appears to be causing the vibration issue...
I’m now onto the 3rd shaft which has been sent out by a supplier - this is of a different design to the two previous refurbished shafts I’d tried. Those ones appeared to be oscillating on the long main beam of the shaft between the gear box and intermediate bearing.
But the later shaft looks very much like the JR type that I had on the car previously, almost identical infact.
However the car still shakes... This is at its most pronounced in 2nd gear from low to mid RPMs right where the boost picks up.
Like the other two shafts when I put the old JR one back on the car the vibration is gone!
My N/S replacement is absolutely fine, it just really does point at the O/S shaft causing the problem! Even though this new one appears to have no play whatsoever.
This leads me to think that the old one is so shot that it’s dampening vibrations, whereas the new ones are probably all fine and that’s the problem lies elsewhere though I have checked the following:

Tyre pressures (also rotated wheels front to back)
Wheels balanced in March
Ball joints
Tie rods
Drop links
Wheel bearings
Top mounts
Wishbone bushes

I cannot imagine it would be the alignment, the tracks straight and true.

So what’s causing it??!!!!?

[Yobbo]

To further add to my above ramblings, I may have been unlucky - this latest shaft does have quite a lot of lateral play into and out of the inner CV.
Anyway the old JR shaft is back on the car for the 4th time in this saga.

[Yobbo]

Further progress - I have been informed by my supplier that the O/S(driver's) driveshaft is spec'd at being 960mm long whereas the Focus ST ones I've been fitting are designed to be 955mm.
This may well be the bottom line here, as the universal joint is being pulled out of the cup which causes the vibration.

I've got a Volvo exchange shaft coming in a couple of days so will see if this puts a line under this.

[Yobbo]

Now fitted a 4th replacement O/S driveshaft - this time a refurbished Volvo one form Shaftec which has the bigger diameter hollow long shaft, looks a quality component etc...

WOBBLE IS STILL THERE, particularly in 2nd gear at low rpms - 1.6k-2.2k

I am utterly baffled... Does it need "bedding in"? Is my wheel alignment off?
Is it my differential? Is it my DMF? Is the "uprated" J&R shaft so lax that it's dampening the vibrations from a failing DMF which may have become present over time and that the new shaft components are so tight that it is amplifying the resonant vibration through the car. Is this real life, or is this just fantasy??

At this stage I am reluctant to get back to my supplier as he really has gone out of the way to help me on this matter, I think the next thing to try is getting my wheel alignment sorted as the toe might be messed up or something.