Any suggestions?, Suspension problem on DiscoII

Hi All
Newbie here acting on behalf of my father in law who owns a DiscoII Td5 in Mauritius.
He's having problems with the self-levelling rear suspension and the dealership(?) over there profess to not having a clue whats wrong with it (or so he says - my french isnt good enough to question this!)
Here's whats happening - Under normal conditions (i.e.only himself in the vehicle) everything is fine, problems happen when a load of some sort appears in the rear ; some time after this happens the self levelling suspension ride height drops so the rear of the car is sitting on the bump stops making the ride somewhat unpleasant for those of us sitting in the rear (my wife and I can attest to this as it happened to us when we were picked up from the airport, giving us a very uncomfortable 40 mins or so feeling like we were sat on a plank between the two rear wheels! - took my back 2 days to recover lol)
Anyway, this condition remains until the car is unloaded, then it self- levels again within a period varying from a hour or two to overnight - depending on when he next ran the engine I suppose.
Any ideas on whats causing this?, i'd like to solve it for him as he's a cantankerous old git who doesnt listen to other peoples opinions. (and my back just couldnt take it anymore)
Fingers point to a leak in the air spring, but why would it self level?

//Addendum:The drop is equal - not lower on one side or the other, does this discount a leaking air spring, i assume if one spring leaking then the disco will drop on that side only(?), or will a leaking spring be the point of release for the whole pneumatic system?
Also, why does this only happen when the rear is loaded up, if its leaking wouldnt it consistently drop overnight?

maybe a very small leak and the extra weight is too much for it to cope with.. dunno just an idea.. where abart in france is it?

Hi,
Its not in France (I wish it was, its a damn sight nearer)
Mauritius is an island off the East coast of Africa approx 6500 miles away from the UK. Only one dealer and they only provide sales, not spares/ repairs (apart from warranty, but this is a 2002ish model)
I've had a look on one or two spares websites, they list the air springs as spares but not the hoses / pipes. Are these dealer issue only?

This is from the RAVE workshop manual.

It could be bad news or good news, but the former is more likely because it is a LandRover.

The fact it comes back tio height means the air bags must be OK.
It's the SYSTEM that's letting you down, so to speak.

Read and think and come back to us.
It may be that one of these height sensors has come adrift, lost its cable, or even better, that the system has blown a fuse!

There are at least two fuses involved.
Check the handbook, find the fuses and check them!

CharlesY


Quote from manual
Two height sensors are located on the outside of each chassis longitudinal forward of the rear axle. Each sensor body
is attached to a fabricated bracket and secured with two screws. The sensor is attached to the top of each radius arm
by an arm, a link and two link ends. The link ends allow articulation of the arm to allow for suspension travel. The lower
link arm is attached to a lug of the top of the radius arm and is secured with a bolt and locknut.
The sensor body and arm are manufactured from moulded nylon. The two link ends are made from natural rubber
and the link is made from mild steel. The rubber link ends allow flexibility of the arm and resistance to damage.
Each sensor is connected to the main chassis harness by a multiplug. The three pin multiplug provides an earth, a 5
V supply voltage and an output signal voltage to the SLABS ECU.
Each sensor operates on the Hall effect principle. A magnet is attached to the shaft and rotates with movement of the
arm. The magnetic flux generated acts on a Hall effect sensor and depending on its position varies the current across
the sensor. This current is measured and amplified and passed to the SLABS ECU as a linear output voltage signal,
which varies depending on the angular position of the sensor. The signal information is processed and the ECU can
determine the vehicle height.
When the sensors are replaced or removed for any reason, a calibration procedure is required to recalibrate the
sensors and the SLABS ECU. The calibration procedure requires the use of TestBook and calibration blocks to set
the axle to chassis height to a known value.
If faults occur with the height sensors, fault codes are stored in the SLABS ECU. The current and past fault codes can
be retrieved with TestBook.

Cheers charles
Got a copy of the rave CD (cheers sheddy) and had a look for myself.

I remember checking one of the fuses as per owners manual - i think it was fuse 18 as I thought it may have been the problem but it was fine.

I'm being led to think its linked to the SLABS ECU as when the SLS 'drops' the ABS warning light comes on, as well as warning light for the Controlled descent mode (possibly linked to the suspension being past its lower limit). Think its fuse 11 supplying this but not holding my breath as whatever it is its intermittent.

Nightmare this as i'm 6000+ miles away from this and cant go see for myself -well not for a year anyway- AARGH!

Wish i could have done more tests but severely hindered as:
1. No internet access over there, even worse, no PC
2. Not my landy, and the old git has a habit of hanging around looking over my shoulder and passing totally irrelevant comment as to what i'm doing.

If i was to replace the height sensors I'd need testbook to recalibrate - bit of a problem over there as i'd like to bet the only dealer doesnt have it.

Reading through the vast amount of owners problems, many appear to be about the self leveling suspension. My brother in law is a ploice officer and drives these for a living and has no end of problems... His advice to me when i was thinking of buying a disco 2 was simply to 'buy a pre '03 one with coils'! I did, a 51 plate, but was going to upgrade to an '04 and said to my wife that IF WE UPGRADE, and self. sus. does go wrong I WILL RIP IT OUT AND FIT COILS!!! If you fix it this time because of a fuse, NEXT time it will probably be the bags....