Air Suspension Pump/Compressor Audi A8 D3 model Replacement
Hope this is of use to someone going forward as I had some very useful pointers and encouragement from Bex.
What are the symptoms? Mine didn’t exhibit any prior noises or symptoms just one day the suspension yellow light of death came on and suddenly my previously smooth chariot became a BMW
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After reading up as much as possible on the system I was lead to the fuse and relay under the passenger side front carpet. Easy enough to replace but a b*gger of a job to fight the thick carpet!
Tried both and each time the fuse blew. I also noticed a strange smell from the car the first time I tried a new fuse which I have since identified as the compressors burnt smell! Always replace the relay with a new compressor anyway so it’s worth trying these steps first.
To remove the existing compressor you need to get under the front near side wing. Jack up the car (use jacking mode of course before starting) secure with either a decent trolley jack or axle stands. I used a trolley jack on the suspension mountings as my axle stands are far too tall, boy you notice how low these A8’s are when you try to work under them! You only need enough lift the get the wheel off and get under the front apron so no need to go too far.
First job is to remove the wheel. Then start with the front wheel arch liner, the plastic one under the front of the wing only, no need to remove the furry one. Some of this is easy with Star bit screws, some of it is plastic clips which break when you try to shift them so be prepared to replace a few. Don’t forget the ones out of sight on the top edge of the wheel arch and under the bottom of the wing. Once you have these out you can wrestle the liner out be careful not to hit or pull any of the wiring, and wear goggles as the sh**e flies everywhere.
Once that’s out set it aside and you should have a view like this this.
You then need to start to remove/loosen the front bumper. There are again star bit screws on the front panel which need to be removed, then a section of plastic cover which clips in across the front behind the grill top. Under this you will see two sections with a piece of foam stuck in. Ease the foam out of each of these with a screwdriver. Under this you will find two further star tip screws/bolts. Remove these.
Now under the front you should see the under-tray secured to the bumper bottom by three flat headed screw/worm fittings. Undo these and remove this frees up the bottom of the bumper from the under-tray.
Now heading back inside the wing looking forward on the left you should see three nuts all 10mm one above the other which are the securing bolts for the bumper. The top one looks bigger as it has another fastening behind it but all you need to remove is the 10mm nuts.. You will need a deep socket as the thread protrudes from the nut. Also a tip I use when faced with this sort of thing is to stick a bit of blue tack or similar on the socket to make sure you don’t go dropping the nut somewhere you will never retrieve it! Your front bumper should now want to come away from the near side enough to get your hands in to do the job. You could remove the whole thing but I found this unnecessary and managed without. Although space is tight to get the final bolt out anyway.
On to removing the faulty compressor. The compressor is installed in and aluminium cage/bracket which insulates it from the chassis of the car using sprung links with fitted rubbers. The cage is held in place with three star bit bolts. The first accessible easily from the inside of the wheel arch, on the right of the cage. The second is on the left and it a tight squeeze as the air pipes and some cables run near. This pales into insignificance when you see the third. This is positioned under a black plastic box underneath the headlight unit. Removing the headlight isn’t worth it as the box is a separate section so would mean further dismantling.
I found it impossible to get a ratchet with the star bit in so managed to get the bit positioned in the bolt head with a ring spanner around the hex of the bit. Now the fiddly bit. Keep a finger on the top of the bit to keep it in the bolt and work the spanner by engaging it on the hex section them dropping it around the lower section of the bit to return then up onto the hex section again to make a half turn hope that makes sense. The bolt comes out with your fingers once loosened so only a few turns of the improvised ratchet are required.
You are then left with the two pipes and the three electrical connectors. Release the connectors and move to one side, the wires are clipped into the cage so just lever the clip out the front of the cage and this can be used again. I think there is also a similar clip towards the front of the cage under the headlight. Remove this as it will prevent you getting the thing out otherwise. The larger rubber pipe has a clip around it, like the sort often used on petrol pipes in older cars. This pipe runs up the side of the wing and the connector has some foam strapped around it. This needs to be compressed slightly with pliers and lower down the pipe the pipe can then be removed from the connector, as it’s just a push fit.
The smaller pipe is connected via a screwed brass fitting you can see this on the compressor facing towards the rear just behind the section of the cage facing towards the rear of the car. I think this was a 10mm spanner, go carefully and don’t bend the metal pipe section.
You should now be able to remove the unit with a bit of wiggling about. Here’s a picture of the area pump removed.
You then need to remove the old one from the cage. I took pictures so I knew where to run the wires and pipes as these need to have the clips taken off the old one and fitted to the new as the new one didn’t come with any. You also need to use three or four cable ties to secure the cables to the clips. Three sprung mounts hold the compressor into the cage. Undo these and then fit the rubbers to the new pump, again mine didn’t come with new rubbers surprisingly. Here’s the new one fitted up ready. Doesn’t look much for nearly £1,000 !!
Head back to the car and fitting is the reverse of the removal. As you refit the bumper, use something to lift the under-tray up as this allows the bumper to slot home easily. Again use the blue tack on the nuts of the bumper fitting or you will be hunting for them!!
Take it easy with the brass pipe connector and make sure you tie wrap any wires back to where they were and place the clips for the wires back into the relevant sections of the cage. I gave the wheel arch liner a good clean for good measure and this stops the muck coming off into your eyes!
Once assembled I fitted a new 40 am fuse in the block beneath the carpet (Near side front). Nervously started the car up only to see the yellow warning lamp of death was still glowing. At this point I nearly cried! I was about to start stripping things down again to make sure I hadn’t left a loose connector or something, when I went back in the car to put it into jacking mode. However it was still in jacking mode. So I started her up again set jacking mode to “no” and hey presto the light went out and everything has been fine since. To say I let out a sigh of relief was an understatement!!
Overall it is not a hard job just fiddly and needs a steady approach with patience.
Here she is restored to her normal comforting ride I hope this helps someone have a go at this job. Conan if this is ok happy for it to be stickied or if you need in another format let me know . I also have a document on removing the bumper from another site and an Audi tech guide (audi self study guide for their techs) on the suspension system in PDF cheers Glyn
