Help please! Sunken rear end.

I have recently spent four days under my Discovery 2 treating the chassis with Bilt Hamber UB wax sealant. The car has had its wheels off, and when I did the back end it has been on axle stands (positioned under the rear axle). Yesterday I noticed that the rear end had sunk down. A picture is attached. Can someone help by telling me what has caused this, and in particular how to rectify it?


Might it be because I took some electronic component off both sides of the mid-/rear chassis to wax treat the bracket that it was screwed into. I have attached a photo of this also. As can be seen, this component had split at each female screw thread point.

I started the engine in the hope that maybe some sensor would pick up that the car was back together again and re-align the ride hide, but though the engine started fine, it cut out after a few seconds. Now, I also changed the fuel filter (which lost some fuel), and the tank was low anyway, but I didn't think that it was so low as to starve the engine of diesel.
So, please, can someone help?
Thanks,
Andrew

those components are the height sensors, ensure all doors are shut otherwise it wont raise,jacking the car up will mean it drops the air out of the air springs, the car will try to self level by letting air out, removing the height sensors will drop it too ,they sometimes take awhile for compressor to kick in if youve messed with the system

Thanks. So should it rectify itself? Do I need to get the engine going for this to happen?

The pump will only run when the engine is running, do you don't flatten the battery

Thanks again. So it should pump itself back up. I therefore need to find out why the engine cut out a couple of seconds after starting, which may be due to me replacing the fuel filter. I'll check out the electrics now. Any other ideas would be welcome. I don't suppose me spraying wax treatment around the top of the air spring could have done any harm could it?
Andrew

It should pump itself back up once the engine is running, yes. It might take a while if the tank is low on air and as said, all doors need to be closed

ANR said:

Thanks again. So it should pump itself back up. I therefore need to find out why the engine cut out a couple of seconds after starting, which may be due to me replacing the fuel filter. I'll check out the electrics now. Any other ideas would be welcome. I don't suppose me spraying wax treatment around the top of the air spring could have done any harm could it?
Andrew

Click to expand...

fuel filter change would be the isue they can take a bit of purging after filter replacement
the wax wont hurt

Great. Thank you all very much.
I got the engine going: the fuel filter electric plug didn't seem very tight, so I cleaned it up and forced it in a bit further, then persevered with cranking the engine until it fired up. My question was to be: how long will the pump take to level the car out, as after a couple of minutes there was no change. I'll leave the engine running a bit longer.
Thanks again.
Andrew

Is the pump running? You should hear/feel it. Doors shut and foot off the brake?

All sorted now. It was back to normal ride height in a few minutes. Thanks again, for both your help.
Andrew

Since both my ride height sensors are held on with cable ties and wire because all screw holes and rubber separators are split, can someone tell me please: if I replace these ride height sensors with new ones, will the car re-stabilise or will its ride height need calibrating?
Thanks,
Andrew

height sensors need to be static or you'll have problems. I can't imagine cable ties will eliminate ALL movement

Thanks. I understand what you are telling me. The cable ties and wire are just a temporary measure. I wanted to know whether I could replace them myself (without having any equipment to calibrate them) or whether I should drive it to a garage. The ride height is now perfect.
As I have thought about this, perhaps where I went wrong was not disconnecting them from the battery? If I disconnect the battery first, will the ride height remain stable while I replace each sensor, and then (as per my last question) will the new sensors stabilise the vehicle without needing a new calibration?
Andrew

disconnecting the battery will mean the airbags can't level and will only sink if there is a leak
I would expect different sensors to give slightly different readings and may well need adjustment, but you may get lucky, i'm not sure on this.

I believe a simple calibration can be carried out. Ignition on, engine off. Keep electrical connections connected.
Take lower part of actuator arm off the locator, it is a push fit. Then slowly move it up and down through it's movement. Do with both sides and ensure they are fitted correctly. Shut doors, start engine, cross fingers.

ANR said:

Great. Thank you all very much.
I got the engine going: the fuel filter electric plug didn't seem very tight, so I cleaned it up and forced it in a bit further, then persevered with cranking the engine until it fired up. My question was to be: how long will the pump take to level the car out, as after a couple of minutes there was no change. I'll leave the engine running a bit longer.
Thanks again.
Andrew

Click to expand...

I believe the plug on the fuel filter is the Water in Fuel warning, I do not think it has to be connected for the system to work ?

I did my ride height sensors only couple of months back, disconnect battery negative then jack up do the job then reconnect neg terminal, fire her up with drivers window open, door shut, due to disconnecting battery neg car won’t know it’s had new sensors so will pump up to its usual settings/ level, press rear lift button dash to make sure it goes up then again to lower.

Can someone please give me a bit of detail about how the ride height sensors work? I have had a garage replace and calibrate them.
I want to buy a trailer, and my tow ball (while the vehicle is unladen) appears to be quite high. Its midpoint is 480mm, so higher than the EU Directive specifications. But the EU Directive says that this should measured at laden weight. What I want to know is, will the ride height sensors re-adjust while the vehicle is being driven, to compensate for laden weight, i.e. will they increase upward force to restore the vehicle to its unladen 'ride' height? In short, will the towball height measured while unladen be the same when laden because of the ride height sensors? I suppose I could do some experiments with a tape measure and a group of people/load.
Thanks,
Andrew

yes, the air suspension should keep the ride height at the correct level, regardless of load
check the ride height was set correctly by the garage, I'm sure someone will be along with correct measurements

I do not tow a trailer but I have had some quite HEAVY loads in the back, and no I don't mean the Mother-in-Law
Once doors are closed and engine running air suspension on my Disco' 2 adjusts itself and car sits level.