awdinut

I have watched Youtube videos showing how to replace the 'piston ring' in the pump cylinder. But my kit also contains a bag of dessicant crystals. I know that Mercedes and others use the same compressor model, but with varying system designs, so I they may have been included for another make of car. Anyone know if there is somewhere in the A8 system that needs crystals replaced ?

Jack88

Yes, and it's very easy. There are two very long bolts that have nuts on the end of them holding one end of the body of the compressor on, acting like a lid. Simply take that off, dump out the old, and put in the new. My desiccant was well used up when I dumped it out.

awdinut

Is the "lid" the end opposite the cylinder ?

a_very_naudi_guy

Do the forum a favor (I plan on doing this shortly) and take photos of every step of the way, and any caveats/notes/gotchas you run into and make this into an instructional thread for the gaskets/dessicant/etc replacement / "refurb" of the compressor.

Thank you!

ltooz_a6_a8_q7

Mind as well get ready to buy a new one if you're gonna do this... because chances are it wouldn't help but breaking it in the process. If the air system is air tight, the pump should last for many strut replacements. Before opening it up, do the output test, not using VCDS, but real pressure gauge to see if it's within specs if you know what specs is.
Cheers,
Louis
PS: I did buy a set for $17 and collecting dust in the garage when my strut failed almost 2 years ago.

cu52

I rebuilt mine last week Pretty quickly as I did not have a lot of time. Used the bagpiping andy kit:https://www.ebay.co.uk/itm/Audi-A8-S...SWTp:rk:4:pf:0

There are no crystals in that. What are the crystals for? Absorb water? Where do they go?

I would have documented but I used this video, except I left the pump in the car and worked upside down.

Jack88

Undo the 2 nuts shown and you can remove the bolts to be able to pull it apart to access the chamber holding the desiccant. Easy!

cu52

So this chamber should not be empty?

Jack88

It should be. Sorry, the desiccant is in the cylinder. I can't remember if the plastic round bit is snapped in place or twists in place. Behind that metal plate is a fabric filter and the desiccant behind that.