Shuddering when driving - Bad P/S?

[Ilikemice]

Hello all. I haven't been on here for a while as I've been busy working, and had no faults with the Explorer, until today.

I was driving back from its MOT, which it flew through with no advisories

Driving home I was going round a roundabout and the steering wheel started shaking back and forth violently. It stopped when I slowed to come off the island. Then when driving along it started up again, the whole car shaking violently. It stopped when I slowed then after driving for a bit I hit a slight pothole which sent the car crazy again until I pulled over.

Google suggests anything from ball joints to tie rods but it passed MOT a couple of hours before. Could it be bad power steering pump? The brakes seem a little more responsive than they did before but that could be down to the tester moving my seat so it feels different!

It also happened to a minor degree when backing slowly into my drive. I've had a very minor version of it a while back when maneuvering slowly. Research suggests a new P/S pump is in order, or there's air in the pump.

Any ideas are appreciated!

Edit: My dad reckons it's because they may have jacked it up and steered it or wiggled the wheels and introduced air into the system during the MOT. I took it for a drive and it seems okay apart from a slight shaking when reversing into the drive

 

[rich uk]

Transfer case ?

mine did it once..... locked up all the wheels in auto ..flipped the switch 4wH back to auto and it aint happened since..

juddering was bad....

 

[Ilikemice]

I'll try that tomorrow, thanks. My dad suggested the 4x4 system but I only got as far as seeing if it was still in auto.

 

[corkey]

i would bet they moved the wheels side to side during the inspection and got air in the system, go do some figure 8's in a parking lot and that will go away,

 

[janolsson]

As corkey says
When they inspect the front end they have the wheels off the ground and turn the wheels this way and that without the engine running. This introduces air and causes vibration. Find a bit of grass and with the engine running turn the wheel from lock to lock a few times (don't hold it at lock as this stresses the pump)
On an additional note if you have the ARC on the rear do a reset procedure as the rear will have been jacked up to.

 

[Ilikemice]

Cheers guys. It seems it was air in the system. It's been behaving itself since

 

[BIGHVM]

Yes, I too shudder, mainly in winter on the cold leather seats!
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