Thread: Rear Air Suspension D2

A cannot comment on the noise, my first reaction was that its just the standard "creeking" you hear from suspension over speed humps. Then again if its annoyingly loud thats something else??

as for the SLS operation, here's an overview of what happens:

The rear Self Levelling Suspension (SLS) is monitored by the Self Levelling Anti Lock Braking System (SLABS) ECU behind the glovebox and recieves a voltage signal from two (one each side) sensors informing it how low or high the rear of the car is compared to its calibrated "normal" height

If it reads low, a signal is sent to the WABCO compressor (located mid-chassis under car on near side) to pump air into both airbags. If high, a signal is sent to vent air (from the exhaust port located at the compressor) it will do this all the time the engine is running. You may notice the SLS adjusting itself almost every time you pull up to a stop.

When the engine is turned off and a door opened, the SLABS unit will continue to monitor for 1/2 hr and if required signal to vent air from the airbags to maintain the normal road height. (ie when lightening the car as you unload camping gear). It wont vent air if it detects rear axle is articulated by 100mm or more as a safety precaution.

At speeds up to 30km/h in high or low range you can engage the "off road mode" function with the button on the dash to raise the rear by 40mm. A good working compressor should do this in around 20-25 seconds. Raise it, drive above 30km/h and you'll hear 3 chimes as it automatically lowers back to normal height.

If the SLABS detects a grounded chassis (hung on a rock) it will automatically pump air to the airbags to try to free itself, this is called "extended mode"

Key components, costs (in AUD and if bought from LR) and issues are:
1. WABCO Compressor ($1000) have around a 10 year life, 45 min to replace and can be bought much cheaper from USA or UK. Can be refurbished but no "official" repair kit exists. Problems can be from general compressor wear and "sticky" vent valve.
2. SLABS ECU ($?) no idea!!
3. 2 x Airbags ($840ea) These do eventually wear out, particularly at the fold. 10 years seems average, if leaking, spraying with soapy water will reveal bubbles. 1hr to replace both (Dunlop type are much cheaper and Arnott Ind are abour 1/4 of the LR price).
4. Air Filter ($25) 15 mins to replace (located behind rear n/s light cluster) Not normally changed at regular servicing so watch this youself and replace after long dusty trips.

best of luck

Do u have ACE by chance, As it may be the rear sway bar bushes that can go.
Or even the watts linkage

Hi Guys,

Thanks so much for the info. i have alot of experince with other cars, just not discos.

It's definately not SLS issue from what I can asertain, more traditional suspension related. If you around when the old Falcons used to make that worn suspension noise when they went over bumps etc, because mechanics forgot to grease the nipples, it's that sort of sound.

It is standard creaking that is how I would descibe it, however it's very loud.

Sniegy, yes I do have ACE, so your suggestion could be correct, I don't think however that it's anything major.

just want to try to fix it myself, but want to try and start in the right area. not sure how I am going to diagnose it though.

They sure are tempremental cars, that's for sure but something about them I just like hence why I bought one.
Well actually the whole reason was to have a much cheaper car in the driveway for a few years, that would'nt cost us that much........

I get a noise too but I think mine is in compression, loading up the air bags coming off a speed bump as the car settles down in the back. I have new shocks and did not make a difference. Have wondered at times if it is just the mud flaps connecting with the top of the speed hump while the wheel is settling down at road level but I think it is probably just in the bushes. It is an old shocky sort of noise like a falcon as you say.

Originally Posted by JayBee75

Hi Guys,

Thanks so much for the info. i have alot of experince with other cars, just not discos.

It's definately not SLS issue from what I can asertain, more traditional suspension related. If you around when the old Falcons used to make that worn suspension noise when they went over bumps etc, because mechanics forgot to grease the nipples, it's that sort of sound.

It is standard creaking that is how I would descibe it, however it's very loud.

Sniegy, yes I do have ACE, so your suggestion could be correct, I don't think however that it's anything major.

just want to try to fix it myself, but want to try and start in the right area. not sure how I am going to diagnose it though.

They sure are tempremental cars, that's for sure but something about them I just like hence why I bought one.
Well actually the whole reason was to have a much cheaper car in the driveway for a few years, that would'nt cost us that much........

mine did that
$7.00 for bushes 1/2 hr time dead easy to change
fixed a treat

cheers