ACE problem?

I have a 2000 disco II with air suspension and ace, covered over 150k with no problems (well, one visit from the 3 amigos). Today, having not been used for a few days she behaved strangely - very harsh over bumps. I stopped and the back left side was pumped up to the top of its travel! Going home, slowly, was even more jolting, and now the front left is pumped up - with a disco there is a lot of space between wheel and wheelarch now!
At fist I thought the air suspension might be the cause, but that would not do the front - could an ACE failure make it think I'm constantly cornering? As it stays pumped up when engine off, it is hydraulic rather than electric?
There are no warning lights (yet!) but I cannot find any other web references - any ideas would be very helpful!
Thanks
Paul.

Some info on the ACE system, not sure if it will help you much though. All I can suggest is checking the fluid level and perhaps do a fluid and filter change -

Lateral acceleration of the body is sensed by two accelerometers and signals are transmitted to the ECU. The engine
driven hydraulic pump supplies a constant hydraulic flow to the valve block. Two directional control valves are
solenoid operated by the ECU and these supply fluid to the applicable side of each actuator to apply an equal and
opposite force to the torsion bar. In operation the ACE system maintains the attitude of the vehicle body when
cornering.
The ACE system uses a semi-synthetic hydraulic fluid which is the same as the fluid used for the PAS system. The
total capacity of the ACE system is 1.62 litres (0.42 US Gallons).
CAUTION: The ACE hydraulic system is extremely sensitive to the ingress of dirt or debris. The smallest
amount could render the system unserviceable. It is imperative that the following precautions are taken.
l ACE components are thoroughly cleaned externally before work commences;
l all opened pipe and module ports are capped immediately;
l all fluid is stored in and administered through clean containers.
In the event of an ECU or hydraulic failure the system will fail safe to a ’locked bars’ condition. The ’locked bars’
condition will allow the torsion bars to operate in a similar manner as conventional ’passive’ anti-roll bars. Prolonged
cornering forces will allow a progressive increase in roll angle due to hydraulic leakage through the actuators and
valve block. Failures will be relayed to the driver by the illumination of the ACE warning lamp in the instrument pack.
Faults are recorded by the ECU and can be retrieved using TestBook.
When the ignition switch is moved to position II, the warning lamp will illuminate for two seconds to check functionality.
The warning lamp functionality can also be checked using TestBook.
TestBook must also be used to perform a bleeding procedure after maintenance operations have been performed to
ensure that complete system bleeding is performed. Trapped air in the system can seriously reduce the system
performance.
Fluid reservoir
The moulded plastic fluid reservoir is mounted on the left hand side of the engine compartment on a bracket which is
attached to the inner wing. The reservoir is dual purpose, being divided into two separate chambers; one for the ACE
system and one for the PAS system. Each chamber has its own filler neck and cap and is identified by moulded
lettering on the reservoir adjacent to each filler.
A non-serviceable filter assembly is fitted in the base of each chamber. The filter is made from fine stainless steel
mesh which is moulded into the body of the reservoir. The filter removes particulate matter from the fluid before it is
drawn into the hydraulic pump.
Upper and lower fluid level marks are moulded onto the reservoir body. The capacity of the ACE reservoir chamber
to the upper level mark is 0.5 litre (0.13 US Gallon).

It's the air suspension. The ride height sensor.

Mine did exactly as you described then the suspension exploded.

do the following ASAP it will take you 5 minutes...

you can get to the compressor safely without having to get under the car...

remove the cover from the compressor unit on the chassis under the passenger seat

use a 10mm spanner to loosen the two outer pipes from the three in the valve block, just enough to let enough air out of the suspension and level the car with a slight droop to the back end. tighten them pipes up, close all the doors and the tailgate, open the drivers window. start the car through the window stand back and watch what happens.

stand back and DONT fiddle about in the rear wheel aches whatever you do...

If the suspension rises back to it's lopsided state. suspect a faulty ride height sensor and get it replaced before driving it another mile.

Mine over inflated the air bag and it exploded. Luckily I was stationary... at 40mph it would have been a differnt story..!

Thanks for those replies!

I thought that the air suspension was innocent as it is the front that is wonky! However, the compressor was working hard - I thought trying to get the back as wonky as the front!
I will have a look at the weekend and see what happens!

Thanks
Paul.

yep... mine started with the compressor working overtime the misses asked why her seat was vibrating... Oh ERR!!

mate... dont get you arms anywhere inside the rear wheel arches till you get it sorted... If it pops, it'll drop onto it's bump stops instantly with the sound of a bomb going off!!

It wouldnt hurt to give it a complete change:
Ride Height sensors about £25 each
Air Bags about £90 each.