D2 rear air suspension sagging, after new springs fitted

Hi All,
I am still having trouble with our 2001 Discovery 2 TD5’s rear air suspension. So any advice would be welcome.

It used to drop after about two weeks of no use, but now getting more frequent. Drivers side dropping more than the passenger side.

Read the forums and everything pointed to the air springs, even though no leaks could be found.

New air springs fitted (ouch!), but once to correct height, drops within hours, just as it did just prior the changing the springs. This happens in O/R mode as well.

Compressor inflates almost straight away, no signs of a leaks anywhere.

Where should I be looking now?

The battery had gone flat sometime ago, could the load sensors lose their position?

Is there a procedure for disconnecting them to clean contacts up?

Will they find their position if I inflate system, disconnect battery, unplug sensors, re-connect battery then plug in sensors.

I know there will be those of you out there saying go to coils, but.

You wouldn’t buy a Breitling watch, then check the time on your mobile.

Many thanks

Mike

Totally agreed about keeping the air suspension.

I would be looking at the valve block inside the compressor housing or failing that the air pipes between the valve block and the air springs. Some people have reported them rubbing through on the chassis.

It seems that new valve blocks are hard or impossible to source separately and it needs to be obtained with a new compressor as a complete assembly.

The air pipes weren't great news either, even LR seemingly unable to source them due to the supplier going bust but this situation may well have been resolved now.

Good luck, let us know what you find.

David

It's not from the sensors if the car is rising to the normal height without probs....maybe a valve inside the compressor housing or an ECU problem....though these might have warned u on the dash....unlike it is just a leak somewhere.

Have you sprayed over all the pipe joints and compressor with soapy water?

Hi,
All joints sprayed, but will do again and double check pipework. At the view seems to be a solvable problem and not electronic.

Keep ideas coming, all welcome.

Thanks

mike

Ive gotta jump into this one, because two people who (imo) know the subject are both on line with this. First problem is I am disabled. I can get under my vehicle. So for anything below hip level I have to use a mechanic. I have a problem with my air springs. At rest the vehicle leans to the left, and the backend is lower than the front. I am not even sure the compresser is working. When I park up a few second after I switch off I get a metallic "ping" from the rear axel. I know I have a problem. First mechanic jumped on the tow hook. The backend bounced. "no problem " Second garage looked at it. " No light on the dash, no problem". Are they right? I cant see the light being the ultimate answer. I know its not sitting right. Reading this thread it appears that things can be wrong and the "light" may not show the failure. If this is the case I will not mess about with the clowns, its down to LR Malaga and no beer until Christmas.

I`m not an expert, but have you double checked your ride hight sensors, if not check the inside side of the rubber bush, I found mine was cracked, changed them and all seems well.

spanishlair said:

Ive gotta jump into this one, because two people who (imo) know the subject are both on line with this. First problem is I am disabled. I can get under my vehicle. So for anything below hip level I have to use a mechanic. I have a problem with my air springs. At rest the vehicle leans to the left, and the backend is lower than the front. I am not even sure the compresser is working. When I park up a few second after I switch off I get a metallic "ping" from the rear axel. I know I have a problem. First mechanic jumped on the tow hook. The backend bounced. "no problem " Second garage looked at it. " No light on the dash, no problem". Are they right? I cant see the light being the ultimate answer. I know its not sitting right. Reading this thread it appears that things can be wrong and the "light" may not show the failure. If this is the case I will not mess about with the clowns, its down to LR Malaga and no beer until Christmas.

Click to expand...

The warning light covers just the management issues or the "clean" electrical failures. First of all check the SLS fuse from engine bay F11(30A) and Relay R5 if u think the compressor is not working....u can also push ORM switch to see if it raises.........could also be a door/taildoor switch which if is faulty the compressor will not work. See RAVE > Rear Suspension> Description SLS > page 64 -19 and u'll know more.

sierrafery said:

The warning light covers just the management issues or the "clean" electrical failures. First of all check the SLS fuse from engine bay F11(30A) and Relay R5 if u think the compressor is not working....u can also push ORM switch to see if it raises.........could also be a door/taildoor switch which if is faulty the compressor will not work. See RAVE > Rear Suspension> Description SLS > page 64 -19 and u'll know more.

Click to expand...

Thanks Sierrafery. I have done the ORM thing in front of them . Nothing moves. They are fixated by the fact no light is on no problem . I will have a look at the fuse in daylight and hope thats it.. otherwise its off to LR Malaga.. The workshop is cleaner than my house, and its air conditioned !

Don't waste your money yet ......u need a good electrician not a mechanic.......even if he's not a LR expert with the diagram and operation mode from RAVE he must be able to sort it out......another thing.... is the warning lamp working on self check after ignition?....just to be sure.....and as i said even a f***in door switch could make u trouble if it's not making contact......the SLS is projected to not raise with open doors/taildoor.......some measurements needed.

I almost forgot u have to check fusible link FL9/30A too..... this one is actually feeding the compressor via the relay

when you exit the car you should hear air rushing out and it should drop the back end by about 2cm....

however, if the compressor has failed, then when you start her up again, she wont rise and therefore will not fall again when you get out next time. the ride height sensors will overwrite this function.

first, does it drop by about 2cm when you get out and close up?

secondly, all door and windows have to be closed before the computer makes any adjustment in height... what does this mean? well it could be that one of your door switches is not playing ball somehow, however you should hear that plip when you try to set the alarm if this is the case. so you could systematically open the doors one at a time and try to set the alarm and the bonnet also. do you get the plip? not a great test and stands to prove not much but worth a go...

both these things you could do without a mechanic.

thirdly, wind down the drivers window and start the car you should be able to hear the compressor kicking in. or you could get someone to simply put their hand on the black box as you start her up. vibration in the box is a sign of the compressor motor spinning and leads you to new conclusions.

my suspision is the compressor has failed, they have a finite life, it is not returning to the ride height correctly, you are down at the back because your air bags are depressurising naturally over time, and one more so than the other...

however that failure may just be an electrical gremlin, so as Sierra said, check the fuses and relays in the main engine fusebox also.

lets take it one stage further, if the compressor has failed, then you could remove it, depending on your disability and skill level this may need a spanner wielding friend with some axle stands, but not really a mechanic...

the most common cause of compressor failure is the carbon motor brushes on the motor, water somehow get's into the motor unit and a combination of rust and carbon powder cause these stupidly small brushes to wear away to nothing. it is not possible to buy replacement brushes (well i couldnt), however I was able to make some replacements by cutting down similar brushes and soldering them in place. I used 'Henry' vacuum cleaner brushes for about £15 from a repair center as they were a similar size and hardness and they had braided tails that could be soldered in place. (can you use a soldering iron??) This gave me another 12months out of a compressor... £15 or £300 for a whole new unit, the maths made sense to me....

http://www.landyzone.co.uk/lz/f38/disco-ii-air-suspension-definitive-guide-61211.html

Thanks for the tip fellas. Still waiting for the auto elec guy to show up. Should have been here yesterday morning !! I have had a go at the things you suggested. All seems OK . The compressor feels like its operating ( slight vibration ) but nothing is happening to the air springs. To confirm this I got the goat boy to get under and put strips of sellotape the length of both springs, then took it for a drive. The theory being that when the suspension rose it would tear off the tape indicating the bags had inflated. Nothing! tape remains intact. Is it possible that the compressor could operate and do nothing ?

spanishlair said:

Is it possible that the compressor could operate and do nothing ?

Click to expand...

Unlikely...... unless the air supply pipe is totally cracked but i think then u must have heard some fssssssss

Hi guys. Still on the case with this one. I waited four days for the guy to turn up to help me. No sign. So I managed to get it looked at in a local garage. Guy is supposed to be good with 4X4s.He put it on the lift. I have never been under a Disco before, and I am not sure he had!! He poked about with a lead light and identified the failed part. It is a piston, about a foot long that sits along side the rear propshaft, just forward of the rear axel. His explanation is the pison lifts the rear, that allows the bags to inflate. He wants to change it tomorrow. I had no idea this piston featured in the air suspension system, in fact I have no idea what part the piston plays in anything. Is there a chance he is right? I cant see it, but what do I know.

Run a mile! Sounds like he thinks the ACE ram is part of the air suspension.

battenberg said:

Run a mile! Sounds like he thinks the ACE ram is part of the air suspension.

Click to expand...

Thank you battenberg, that saved me being mugged up. I went up to the bar and told him.. His fallback is the compressor has failed. When we were under the Disco he identified the compressor as a large shoebox sized thing fixed to the chassis about half way along. It looked far bigger than the one I had seen a picture of on the forum. Now he wants to change that.. No worries Im gone !

He has correctly identified the compressor, it is under the passenger seat. Anyone who knows what they are doing should be able to replace a compressor in about 15mins armed with only a 10mm spanner and a set of axle stands. Someone who doesen't could easily do it themselves. Get yourself a new compressor mail order, then use beer vouchers and someone who is able to help you. Changing a compressor is EASY!, just follow the instructions on here.

The ACE ram is one of two hydraulic, computer controlled rams that act on the antiroll bars to stabalise the body while cornering.

spanishlair said:

Thank you battenberg, that saved me being mugged up. I went up to the bar and told him.. His fallback is the compressor has failed. When we were under the Disco he identified the compressor as a large shoebox sized thing fixed to the chassis about half way along. It looked far bigger than the one I had seen a picture of on the forum. Now he wants to change that.. No worries Im gone !

Click to expand...

First u must be certain that the compressor is gone and it isnt a feed issue.......did he check voltage at the compressor's plug?

No he checked the fuses and the relays. They were fine. Frowned when I explained that the doors need to be shut for the system to operate. Then got excited about what I now know to be the ACE ram. He only mentioned the compressor in passing. It is clear now that he had no idea.