Disco 2 Ride height sensor fault?

I was towing a digger today with our TD5 and the car was behaving fine. I unloaded the digger and started to head home with an empty trailer and the car started to make a knocking noise from the rear. I pulled over and noticed that the O/S rear anti-roll bar link had popped apart. Pulling back onto the road again I noticed that the car was sitting high on the drivers side rear and the air bag had fully inflated. This appears to have popped the link apart.

I am right in thinking that I have a faulty ride height sensor? I can't seem to raise the rear with the button on the dash at the moment. I have read that these are easy to change but that you must disconnect the battery first. Is that correct?

Glen.

Excellent! thanks. No need to disconnect the battery then.

You should always either disconnect the battery or at the very least remove the relay and fusible link for the SLS before working on it. Both are in the fuse box under the bonnet.
If you work on the sensors without disconnecting, you run the risk of losing the calibration.

Before delving into changing sensors, clean the outside of the plugs and disconnect, then clean out both the plug and socket with contact cleaner, IPA or similar,
mate and un-mate the plugs a few times to clean the contacts, then spray again and reconnect.
With more salt on the roads it could just be a contaminated plug, worth doing first and its almost free1
If you do have to replace the sensors, probably best to do them both, think about buying new bolts for the bottom/pivot. Part number is FB108097. they are about about 70p each!
Mine were very seized! So much so, that the last person who worked on them had simply cut through the plastic fitting at the end of the sensor arm and clipped it over the bolt!
I did as biggeee said and dissed the battery, didn't have to recalibrate afterwards.
I guess your airbags are ok!
Mark

Ok. I will make sure that I disconnect the battery. I ordered 2 new sensors (and a new anti-rollbar link) from Island 4x4 on Wednesday evening and they arrived today, so I will fit them at the weekend.
Thanks.

I have got this all back together (as well as changing the rear pads and bleeding the brakes through) except for fitting the new anti-roll bar link, because I can't get the axle high enough to connect to it. I think that the ACE has been affected by the ride height sensor fault and has moved the roll bar up from the axle on the O/S.

Before I reconnect the battery and start the engine, should the car still be on stands under the chassis at this stage, so that the system sorts itself out? Or should it be back on the ground before starting? The definitive guide wasn't too clear.

Hopefully once it is up and running again, the ACE will give me enough slack to reconnect the anti-roll bar link.

dont let it on the bumps before you start it cos the sensors can go out of limits, even if it's not on axle stands jack it up from the towbar to at least half of the normal height before you start the engine

Thanks Sierrafery. I have just followed your advice about using the jack under the towbar and it all seems to be back to normal. Still couldn't get the ant-roll bar link on, so I put a ratchet strap on the bar and around the diff, and that did the trick.