Sunday, April 9, 2017

Oil Drain Access Panel

This was just a quick fun mod I did soon after I got the car to make servicing a bit easier. I stick to a 5k mile oil change interval with filters changed every 10k miles but during track season I'm usually changing just the oil more frequently. The normal procedure for that of course is to remove the 15 or so T25 torx to drop the plastic undertray and then remove the bolts for the aluminum tray. That's all too much work :) Instead I've added a small access panel directly under the oil drain plug and that's attached to the car with quarter-turn fasteners. So for a quick oil drain all I need for tools is the 19mm wrench for the drain plug.

The quarter turn fasteners were sourced from Pro-Bolt. 14mm D-ring with slide on clips.

Some quick pics and measurements for how I did this. You'll note the opening is slightly odd shaped. The original plan was to put a second NACA duct here instead of just a flat cover so that it wouldn't even be noticeable as an access panel. So this panel is quite oversized compared to what's really required.

First a pic of the access hole in the undertray so you can get yourself oriented with where to cut. The left side would be towards the front of the car. There's that big open slot that draw in air that is then deflected up the back side of the engine (note I'd love to build some actual duct work here to direct the air to the turbo area and build a proper chimney, maybe some other day).

The oil drain plug is right at the rear edge of the opening, near the deflector, so really you just need to cut an opening from the very edge of the deflector up a few inches. Be careful to leave enough space around the edges for the quarter-turn fasteners. Mine are about 2cm wide.

That leaves a space about 8.5cm wide. Probably wider than needed but nice to have space to swing the wrench.

And with the cover in place. This is just stock aluminum sheet from the local hardware store and cut to size. I possibly should have left the label maker in the house that day :)
And again, the sizing was all intended to use a NACA duct for the cover so if you're doing this you can just cut a smaller rectangular opening.

And finally a picture of the undertray in place showing the available access. This really only works because the TTRS drain plug is at an angle so the flow of oil just misses the back edge of the undertray. Really all that's needed is an 8.5 x 5 cm hole.

Sunday, February 26, 2017

Gen4 Haldex Controller

The installation instructions supplied by Haldex are pretty good, this isn't a very complicated install. However, there were a few tricks I noted as I ended up installing my controller many times (long story) so I thought I would document them here.

Also, when ordering be sure you order the correct controller for your car. Gen 2 Haldex is physically different from Gen 4 so a Gen 2 controller can not be installed in a Gen 4 coupling.

Within the Gen 4 family however there are several varieties that are all physically the same but different applications. For a TTRS the Haldex coupling is a 0BY unit and you can order a race or competition controller. TTS, GolfR, Tiguan, Passat, etc all are different coupling variants (0BR, 0AY, etc).

The usual disclaimers apply... This should only be an hour install at a shop (really more like 15 minutes) so if you're unsure of what your'e doing take it to someone.

You don't really need any specialty tools for this installation but there is one that can make life much easier. The top allen bolt is in a tight spot with the fuel tank heat shield just a couple inches away. There's not enough clearance for a 1/4" driver socket on a wrench so one of these small drivers with a 4mm allen bit is perfect.

4mm allen - 2 bolts securing the controller
5mm allen - Haldex fill plug in case you need to top it off
channel locks - Might be required if the throttle valve needs some assistance coming out
drain pan - You'll lose a small amount of fluid during the swap

Here's the main controller unit, the throttle valve and the sealing plate as supplied by Haldex. The stocker controller is all exactly the same as this physically. The second picture shows how everything looks assembled once installed.

Also, since the parts are identical to the stock controller you may wish to mark the throttle valve with a sharpie so you don't mix them up. I marked mine on the end of the barrel next to the black electrical connector.

First find the location of the stock controller :) This is ahead of the rear axle and on the driver side of the car (for LHD cars anyway). You can see the main driveshaft coming in to the coupling in the lower left of the frame.

Make sure to bring the throttle valve, controller and drain pan before you get started.

You can just see the red seal peeking out of the bottom of the unit. You'll want to clean around this area a bit before starting so you don't get any dirt/grit/grease into the sealing surface during the swap.

First step will be to release the electrical connectors at the top of the controller. I had the camera up against the bottom of the car to get this picture... you can't get your head up there so you're working a little blind on this but it's not as bad as it seems. The smaller connector on the left does not have enough slack to come down with the controller but the larger connector on the right does. So if you can't get that one disconnected for whatever reason you can wait.

You'll note these are standard VAG electrical connectors which have a small tab that must be pushed down/back to release the internal clip. Here's where the first trick comes in.

If you get directly under the controller you'll note that there's a gap between the controller and the coupling itself and you can see the bottom of the two electrical connectors.

Reach up through the gap and push the connectors forward, as if plugging them in. While holding them that way reach over the top with your other hand and release the clips, you should hear a faint click. If you just reach over the top and push back on the release lever you're also effectively trying to push the plug off at the same time. That puts additional tension on the catch which makes it harder to release.
By holding the plug still while releasing the clip you take that pressure off.

Once the two plugs are disconnected it's time to undo the two bolts holding the controller in place. Remove the top bolt first while leaving the lower bolt tight.

You did remember to bring the new throttle valve with you right? If not get that now :) Also get your drain pan in place under the controller in case there are any leaks as the controller is removed.

With the top bolt out, use one hand to hold the controller firmly in place while removing the lower bolt.

There are two reasons to hold the controller in place like this. As noted in the picture above the throttle valve is plugged in to the controller with a fairly small electrical connector so you don't want the weight of the controller hanging off of that connector.

The second reason is that the Haldex unit may still be under pressure which will cause that throttle valve to pop out as soon as the controller is no longer holding it in place. So hold the controller tight, get the bolt out, and then remove the controller and make sure the throttle valve stays in place.

Here the controller is removed and the throttle valve is still seated in place. There isn't much of the barrel protruding from the coupling so if it is seated tightly you won't be able to pull it out with just your fingers.

Do NOT use the electrical connector for leverage... I know you're thinking about it ;)

If the coupling is still under pressure the throttle valve may just want to pop right out. If the throttle valve is loose then grab the new throttle valve in one hand and pull the old one out and slide the new one in. There is no specific orientation for this to go in, you'll note it spins in place.

You do need to make sure it it seated fully into the coupling. Press directly on the bottom of the barrel and it should sink another 1/8" into place.

You'll lose a small amount of fluid during the swap, maybe a tablespoon total. You don't have to be ninja-quick with this but don't do what I did the first time and pull the valve out with the new valve sitting on the workbench :)

If the throttle valve does not come out on its own you'll need to add some gentle persuasion. I used a set of channel locks with a shop rag wrapped around the jaws so as to not damage the throttle valve.

You don't need to use a ton of force to get the throttle valve out and you're not looking to remove it completely using the channel locks. Just use a little leverage to un-seat the valve body, maybe moving it out 1/8".

Then get the new valve and be ready for the swap. Pop the old one out, slide the new one in. There's no specific orientation for this to be installed, it rotates in place once in. You'll lose a small amount of fluid during the exchange, maybe a tablespoon total.

The barrel of the throttle valve seals deep in the chamber so there will be a small amount of Haldex fluid still running out. I very lightly blew some excess out with a can of compressed air and then wiped down any remaining excess on the outside with a shop rag.

After cleanup you're ready for reassembly. Note the orientation of the electrical connector on the throttle valve below. That matches the position on the controller. Rotate the throttle valve to this position, bring the controller up level with the valve, don't forget to put the red seal in place!

Then slowly mate the controller to the throttle valve. This may take a couple of tries, do not force it in and make sure the throttle valve stays correctly oriented. You'll notice that the sealing plate has 4 fingers that hold the throttle valve securely in place so as you tighten the controller those will ensure that the throttle valve is seated 100%.

Once the controller slides on you can start to thread the lower bolt back into place by hand and then tighten it until it's just about snug but not 100% tight. Then do the top bolt and then go back and tighten both all the way. I noticed that my upper bolt was loose when I started the entire procedure so I reinstalled both with a small amount of medium strength thread locker.

Reconnect the two electrical connectors. You can look up through the gap to see what you're doing.

Depending on how much fluid you lost you may need to top off the Haldex fluid. The fill hole is to the right of the controller on the piece with the three large \ marks, sort of looks like an M I guess, just visible on the far right in this picture. It's a 5mm allen socket to remove.

I used a small syringe with a short length of hose to refill about the same volume that I lost. The part # for the fluid for a Gen4 Haldex coupling is G-060-175-A2.

That's all there is to it. Double check the allen bolts and electrical connectors are tight and take it for a short test drive. Verify afterwards that there's no fluid leaking from the bottom of the controller.

Tuesday, March 22, 2016

Osir TTRS EX side skirt install

I had been interested in a set of these carbon fiber side skirts for quite some time but I hTad only ever seen one picture of them installed on a car in the wild and there were no install instructions so I had been a bit hesitant. After the 034 intake and MTM rear diffuser I kind of fell off the carbon fiber cliff and decided to go for the skirts and an Osir front splitter to complete the look :)

The skirts themselves are pretty large, about 7ft long and 6-9 inches wide although only about 1/2" thick. They're made of what appears to be a fiberglass and carbon fiber. The fiberglass section is hidden under the bottom of the car and then a lip of carbon fiber extends out along the edge of the factory skirts. It's a subtle effect but the profile suits the lines of the car perfectly. It's a great accent piece.

Install took about 6hrs but that was making things up as we went since there were no instructions and then the wellnuts fought a bit at the end and that ended up burning quite a bit of time.

Standard disclaimer. Having large parts of the body fall off while driving down the road, or track, is dangerous. Take it to a bodyshop if you're not sure of what you're doing.

In the pic below the Osir DF-S splitter is sitting on top of the skirts. The carbon itself is very nice quality with the usual glossy finish. You'll notice too that the fiberglass section has cut-outs to clear the jack pads and if you look closely you'll see raised areas that mate up to the factory skirts. These are very helpful as it gives a fixed location for the skirts to mount to the car. I had been slightly worried that these would have no guides and you'd have to eyeball the fitment but they go exactly where they're supposed to live, no guess work.

The factory skirts are attached to the underside of the car using VAG plastic pop rivets. The center rivet portion when seated all the way in pushes the prongs out and that secures the rivet and the bodypart to the unibody.

These are a different variety than I've used in the past and do not come out very cleanly. The cap portion of them is soft plastic that bends easily. Not much chance of reusing these so just grab onto the center portion with a pair of pliers and yank them out.

As mentioned there are no installation instructions included but it appears that Osir wants you to use these plastic rivets on the inner row of holes and then use the included wood screws in the outer row of holes to attach the carbon skirts to the factory skirts. IMO that is grossly inadequate.

What I ended up using for both the inner and outer row of fasteners are something called wellnuts. These are a small nut bonded to a rubber sleeve. They are inserted into a hole in the body, similar to a rivet, and then when a bolt is inserted and torqued down the rubber is pulled down and deforms to stay secured in the body. An alternative to this would be rivnuts like I used on the Unibrace install.
There's 15 per skirt so 30 total and you'll want extras in case you run into problems. The bolts are m5 x 30 and then a fender washer to seat against the Osir skirt.

Anyway, I felt the wellnuts would be a far more secure way to fasten the Osir skirts to the factory skirts. The inner row of wellnuts would be inserted into the unibody and the outer row would just go into the factory skirts. I was wondering how close the outer edge of the factory skirts (ie the part that is visible under the door) was to the unibody. If it would be possible to drill through the factory skirt and attach a fastener to the unibody for the outer holes. Once you get the plastic rivets out you can pull the factory skirt down from the car and peer inside and it is not anywhere close to the unibody. That's good because there's less chance of accidentally drilling into something important but bad because it limits your options for fasteners. In this case I think using the supplied wood screws would not be very strong since they're just going into 1/8" of ABS. The wellnuts should be much stronger and much more durable.

To facilitate using the wellnuts for the outer row of fasteners holes needed to be drilled in the factory skirts. In order for the wellnuts to work they need to be very snug in the holes. We used a step-bit and checked the depth and fitment carefully as we went. You also need to mark these precisely since the inner row of fasteners mates up to those indents in the factory skirt.

Then it's just a matter of drilling both the inner and outer rows for all of the fasteners, note on the inner row you also need to widen the existing pop-rivet holes in the unibody.

We also used some double-sided body tape as some extra insurance. You can see the double row of wellnuts all the way down the length of the factory skirts.

Then it's just a matter of bolting everything up. You want the bolts to be pretty snug going into the wellnuts. They'll get quite tight, just like torquing into a rivnut really. In the end this came out really well. The skirt is mounted quite solidly to the car and I'm not at all concerned that they'll work their way loose.

We did have some problems where the wellnuts would not cinch down and tighten. I'm not sure if they were loose or if the threads got contaminated with carbon fiber dust as the bolt went thru the Osir skirt. We were able to remove most of those troublemakers and use new wellnuts.

I think if I was going to do this again I'd use rivnuts for the inner row of fasteners into the unibody and for the outer row I'd just use standard lock nuts. I'm pretty sure it'd be possible to pull the factory skirts down and away from the body and reach inside to do the outer row of fasteners and then finish with the inner row into the unibody.

After all of that I'm very pleased with the end result :) More pics here.

Sunday, April 19, 2015

Manual transmission and differential oil change

I figured I would do an early service of the transmission, bevel box and differential oils prior to the start  of track season just as preventative maintenance. The car only has 40k on it and would probably be good for at least another 20k but it's cheap insurance.

On the TTRS the bevel box hangs off of the back of the transmission casing and is the power take-off to the Haldex at the rear axle. On the mk1 TT with a similar arrangement the transmission and bevel box shared fluid, on the RS they are completely separate housings.

Here are the stated capacities and part #s for oil. The bevel box and differential use the same type but the gearbox is different. I bought 3 one liter bottles for the gearbox and 2 one liter bottles for the bevel box/differential.

Standard disclaimer. Transmissions are very expensive. Take it to a mechanic if you're not sure of what you're doing.

Transmission oil: G 052 171 A2
Rear diff and bevel box: G 052 145 S2

Transmission: 2.4 liters
Bevel box: 0.9 liters
Rear diff: 1.0 liters

Tools required:
Some sort of fluid pump
5mm allen socket
10mm allen socket
extensions and wrench
M8 triple square, T25 torx, T30 torx (for the undertray)

The procedure for changing the oils is to fill until the fluid runs back out of the fill hole. In order to get the proper amount of fluid in before it overflows the car needs to be as close to level as possible. So get the car securely in the air and level, whether that's on ramps, jack stands or a lift (for the lucky few). Another helpful tip, Always check to make sure you can locate and open the fill plug before opening the drain plug. You don't want to be stuck with the fluid all drained and no way to refill :)

Start by removing the front undertray to get access to the transmission.
The fill plug is on the front of the transmission casing just above the aluminum support. You can see the hose coming out of the intercooler in the background of the picture. The fill plug takes a 10mm allen socket and conveniently has a taper in the seat so no need for a crush washer and you'll know when it's tight.

The drain plug is easy to locate. Just follow the seam down around the bottom and you'll find another 10mm allen plug. Audi was nice enough to use the same fill and drain plugs so it's ok if you swap them. That's the dogbone at left to help orient you.

The drain is a large diameter hole and the fluid comes out fast! It's 2.4 liters worth so be sure you have a large enough pan to catch it all. And it smells pretty bad too.

Once it's drained close up the drain hole and use the pump to slowly fill the 2.4 liters back thru the fill hole until it just starts to seep back out.

Next move around to the bevel box and make sure to switch to the proper oil. You can find the drain and fill holes near the passenger side half shaft. The fill plug is hard to see so start by locating the drain plug. That's the half shaft at the top of the picture and the oil pan and level sensor to the right.

The fill hole is located on the same housing but up higher and tucked back in. Here the long allen socket is in the bolt, you just can't quite see it. The drain hole is bottom center.

This is the same procedure as the gearbox. Drain the housing, close it back up and slowly pump in just about the full contents of a one liter bottle.

Finally move back to the rear axle for the rear differential. NOTE! There are two housings here, the Haldex and the rear differential. These instructions are for servicing the rear differential only, the Haldex uses a completely different fluid and mixing them up will cause damage.
The rear differential is further back and sits behind the swaybar. In this picture the black bar running under the housing is the swaybar, the back of the car is to the right and you can just make out the Haldex controller at center left. This is another 5mm allen socket shown here in the fill plug. The drain plug is also a 5mm allen and is located just over the swaybar, just right of the shadow from the wrench. Same procedure as the other two but this one should take a full 1 liter bottle.

Clean up any drips and double check for leaks before putting the front undertray on and putting the car back on the ground. Take it easy for a bit to make sure the gearbox has a full supply of oil before rowing through a bunch of 7k rpm upshifts :)

I found this page with specifications for all Audi/VW oils. The differential oil is specified as a 75w90 but the transmission oil does not list the weight. The longitudinal transmission oil does say that it's a 75w90 GL-5 synthetic so the transverse oil is probably similar.

Thursday, March 19, 2015

Gen4 Haldex filter

Audi does not specify any change interval for the Gen4 Haldex filter and in fact you won't be able to find a part # for the filter anywhere in the manual or in Etka. I used another guide for vwvortex and these are my notes from doing the swap on my car. Also note that I did this out of sequence with a Haldex fluid change. Overall this isn't a terribly hard project, just annoying the first time as you learn the tricks. I think it took about 30 minutes once the car was on stands.

I sourced the filter from Neuspeed since you can't get it from Audi. Other shops also sell it but make sure that if you have a TT with Gen4 Haldex that you get the correct Gen4 filter. The Gen2 filter is completely different. If your filter cover plate looks like the one in the photos below then you need the Gen4 filter.

You will need a couple of special tools for this, or at least to make it a little easier.
4mm extended wobble tip allen socket (shown below)
5mm allen socket
vise grips
small pick tool
wood screw
eye dropper or syringe
brake clean, towels and drip pan

Here's the socket:

Once the car is safely secured on jack stands you'll be able to find the filter location on the passenger side of the Haldex diff right next to the exhaust and tucked in close to the fuel tank. You should be able to replace the filter without dropping the exhaust. Here you can see the Haldex pump housing and a the top that little plastic bit sticking out (just right of center) is the filter. The second pic is the plate that covers it.

The plate is held on by two 4mm allen screws and you'll see that with the limited access that the wobble socket will come in handy.

It's worth showing a few pics of how the filter is assembled inside of the Haldex housing so you can see what you're dealing with once the cover plate is removed.

First up is the white spacer/seal that sits between the filter and the plate. This has two o-rings to seal against the filter housing. It has a small nipple protruding from the top that fits into a corresponding hole in the cover plate. Then finally that white spacer sits on top of the filter itself and the top of the filter recessed into the bottom of the spacer.
Note that if you're reading the other guy's review he shows a metal spacer, that was actually a crush washer for something else and is not part of the Haldex filter.

So that white spacer is probably the worst part of this. It's recessed into the housing and with two o-rings it seals very tightly and that plastic nipple will break right off if you try to use it to pull the filter out (I tried). The other writeup suggests using a wood screw, threaded into the endcap to pry against. DerTT sends a top tip that the T25 torx screws that are common fasteners on Audis (like the front undertray) also fit perfectly for this application.

Make sure it's threaded in far enough to get a good bite and then use a small pair of vise grips to grab onto the screw and lever that against the Haldex housing and slowly turn the spacer until it comes out.

You'll possibly lose some Haldex fluid during this process and the stuff is very slick and messy so be ready with the drip pan.

The filter may come out with the spacer since it fits into the hole in the bottom. Mine did not. I used a small pick tool to reach into the housing and slide the filter out. It's not in there tight but it's in far enough that I was not able to grab it and the Haldex fluid is ridiculously slippery.

With the old filter out you can bench assemble the new filter and spacer and get ready for reassembly. When reinstalling you want to have the filter securely seated into the bottom of the spacer as you slide them into the Haldex. Make sure you apply Haldex fluid liberally to the o-rings on the spacer to help slide it in and keep them from tearing. In my case this spacer did not want to slide in at all. It's very tight and I believe builds up air pressure behind it. I opened the Haldex fill plug (5mm allen) in an attempt to relieve that pressure but I'm not sure it helped.

Eventually you'll get them seated into the Haldex and the spacer will be sitting just flush with the housing and not recessed as it was when you started. That's ok. When you put the cover plate back on it'll push the filter the rest of the way in. So go ahead and position the plate and replace the two 4mm allen screws. I don't have torque specs for those but they're small and easily stripped so use common sense.

I lost about an ounce of Haldex fluid during the swap and since I wasn't replacing all of the fluid I used a small syringe to add back about an ounce of fluid from a fresh bottle of Haldex fluid. If you're swapping fluid with the filter you won't have to worry about that.

That's about all there is to it. Like I said, not terribly difficult once you know the tricks but even the mk1 Haldex filter is easier to replace and that's saying something! :)

Rear brake pads

Here's a quick writeup on swapping rear brake pads. This is nearly as easy as the front but take it to a mechanic if you're not mechanically inclined. Having your brakes fail because you did something wrong would probably end badly.

Not many tools required for this one:
13mm box wrench or socket
15mm open wrench
Brake caliper windback tool

You don't strictly need the windback tool but it really does make much easier.

I'll assume you've got the car safely supported on jack stands and the rear wheels off. Please do make sure you've got the parking brake released otherwise this will be much harder ;)

This is looking down at the top of the caliper. Remove the 13mm bolt that holds the caliper to the caliper carrier. It's a very shallow head so be careful to not strip it. You'll need to counter hold the in the middle to keep it from turning while you back the bolt out. These should only be tightened to ~30ft lb so you won't need a massive amount of leverage.

With just that top bolt removed you can pivot the caliper back out of the way to get access to the pads. It might take a bit of wiggling back and forth to get it to release from the pads. If it really won't come loose make sure the ebrake is released :)

Just slide the pads out from the side. If you're using factory pads they probably came with new anti-vibration clips. These are the metal clips top and bottom as seen below. They just sit in grooves in the caliper carrier and come right out. If you didn't get new ones it's probably worth removing them and cleaning them up with some brake clean.

Last step in disassembly is to wind the piston back into the caliper so that there's enough room for the new pads to slide in. Be careful when doing this that you don't go too quickly and accidentally tear the boot or piston seal. Also the boot will likely be covered in brake dust, clean that area up before starting.

Just find the correct sized insert for the slots in the piston and wedge the tool in between the piston and caliper and turn the handle slowly to compress the piston. It'll bottom out once it's in all the way.

Slide the anti-vibration clips back into the grooves in the caliper carrier and slide the new pads in too, making sure the friction material is facing the rotors ;)

Rotate the caliper back into place and reinstall the bolt, use the new ones provided if you're using factory pads. Torque the bolt to factory specs (~25 ft lb).

Important! Cycle the brake pedal a few times and test the ebrake to make sure the piston moves correctly and no brake fluid leaks from anywhere.

Caution!! If you don't do the above steps the first time you try to stop the pedal will go to the floor since the piston has been retracted. This unexpected increase in braking distance could result in an accident and potential property damage.

Caution!! Using new pads on an old rotor is not optimal as there are micro grooves worn into the rotor surface so you will not have a lot of actual surface contact between the pads and rotors until the pads bed in.

Wednesday, March 18, 2015

Door panel removal and window switch install

The usual disclaimers apply. The steps below worked for me but if you have other options (power folding mirrors) then things will look a bit different. If you're not comfortable taking the interior apart then take it to a shop, it should only be a couple hours of labor.

I ordered the replacement switches from There are 3 different switch types available with varying amounts of aluminum trim. One of these mentions that it might require slight modification to work in a mk2 TT, the other two are plug and play. The set that I ordered worked out of the box, the part #s are 420 959 851 and 420 959 855. I believe the 420 code denotes these as being R8 parts.

The install is pretty easy to do, I think it took me about 45 minutes per side. The mk2 doors are way easier to get apart and back on than the mk1. The only tricky bit is working with the body clips that secure the door but even those are more forgiving than the typical clips.

Tools required (as far as I can remember):
- T10 torx
- T20
- T25
- Door panel removal tool
- Nylon trim tools
- small screwdrivers

Also if I was going to do this again I'd wrap the door panel tool with either cloth tape or electrical tape to minimize the chances of it gouging the paint under the door panel. Any scratches won't be visible but still ;)

The door is held on by two T25 torx screws, 9 clips and then the top edge is recessed into the door at the window seal. There are then electrical connections and the door release cable that will need to be undone before the panel is free.

First up remove upper speaker grille. You'll want to protect the leather on the armrest here too otherwise the corner of the speaker will dig into the leather (lesson learned the hard way). Start from the corner closest to the top of door handle and work around the top and down the sides. Then you'll be able to reach in and pop the lower center out.

Here you can see the reverse side and where the clips are located. They don't take much force to remove.

Here's what the speaker area looks like. Note the angle of the lower center one, that's why it's a little trickier to get it to release. There's a T25 torx in the upper corner that needs to be removed.

There's a second T25 screw to be removed in the map pocket recess.

You'll want to at least put some painters tape or other protective material around the perimeter of the door to protect the paint while prying the clips off. Try to get the tape tucked under the panel itself to get as much protected as possible.

Now start working the trim tools into the gap between the panel and the door at the lower corner. Once it's pried up a bit you'll be able to peak in and see the clip that holds the panel in place. Slide the door panel tool in the gap and get it in as close to straddling the clip as possible to maximize leverage. As you pop these clips out you want to make sure you've got the tool as close to the clip as possible to minimize any damage to the panel or clip.

Work slowly and apply even force until the clip is popped and then start working up the door careful to pry as close to the clip as possible, there are 3 clips along this outside edge.

Next start working along the bottom edge. Note that when you look into the gap you'll first see clips that hold some wires in place, those aren't the door clips, they're further in (see pic below). Work from the outer edge to the inside edge, there are 3 clips.

Finally start working up the inner edge and release the two remaining clips. I was able to pop these by hand since it was too tight to get the tool in even with the door open all the way.

Here's a view with the panel removed so you can see the location of all of the clips. You can see how far inset the lower clips are in relation to the wire harness.

Two notes of caution with regards to these clips. Even if you think you're prying in the exact correct spot some of these are likely to stay in the door and pop out of the panel itself. That in itself is not horrible as the door panel is pretty resilient and the clips can be reseated later.

Secondly the manual states that the rubber seal around these clips is critical for sealing the door to keep the electronic components dry. If any of those seals are damaged the clips should be replaced.

Here you can see one of mine that was left behind.

Ok, with all of the clips out the door should now be hanging from the top edge in the window trim. Before you lift it off be sure that you're ready for the next steps or have something under the door panel to set it down on, or have a second set of hands to help you out :)

Lift the door panel straight up to clear the recess in the window trim but don't go too far as the panel is still connected to the door itself in a couple of locations.

First reach in and undo the electrical connectors. These take a second to figure out but are easy to remove. Simply push on the raised tab to release the purple clip and then flip the clip up which will push the connector out of the plug. Do the same for any other connectors. If you have the power folding mirrors you'll have more connectors than just the window and mirror controls, and the passenger side will be different than the driver side.

Now you can remove the door release cable. Unhook the white plastic retainer and slide it back. This should then give you enough slack to pop the hook out of the door handle assembly and then the panel itself will be completely free of the door.

Set the panel down careful to protect the interior surface so that it doesn't get damaged, this is a good time to move the project inside the house :). Carefully remove any stuck clips with one of the nylon pry tools.
The back side of the door panel is covered with some thick felt padding. This is just tucked in some clips around the perimeter. Locate these and gently remove the padding from the panel. This will expose all of the internal screws and allow you access to the switches.

Next release the electrical connectors from the window switch and mirror control. These are the typical Audi electrical connectors with a tab that locks the connectors in place. Press on the tab and slide the connector out. If it's hard to remove the connector then you're doing it wrong, back off and try again. With the catch released they come out easily.

The window switches are held in a small plastic cradle which is clipped into the armrest. To get that all out the armrest has to be removed from the panel. Remove the 11 T10 screws holding the armrest and the 3 larger T20 screws holding the door pull in place. Keep track of where the 3 larger screws go. If you lose track you should be able to figure it out when you reassemble everything, they are only used to hold the door pull in place. Also these are all self tapping screws going into plastic so remove and reinstall slowly to not strip them out.

Flip the panel back over and start prying the armrest out. There will be some resistance since there is some adhesive still holding it in place. As you pull the armrest off of the panel the door pull will drop down out of the slot near the door handle. (note my lower speaker grille is removed here, you don't need to do that). Once the armrest is clear pull the door handle from the armrest and set aside.

Now comes the fiddly bit that will take some patience (and those small screwdrivers). The switches are held in a cradle that is clipped into the armrest. This cradle has 4 catches that are easy to release and then it'll pivot out on the 5th catch.

Now flip over the switch assembly and if you look closely you'll see there are 4 clips that hold the switch into the cradle. You need to release all 4 of those while pushing the switch out the bottom of the cradle. This will take a little time and I don't have a really good technique other than using the small screwdrivers and the thin nylon trim tools. Typically when you get one side out the other will clip back in. Maybe inserting a sheet of paper or business card will help.

In any event once the switch is out it's easy enough to pop the new one in, make sure you get the correct orientation.

Then start the reassembly process following the reverse of the disassembly. Pop the switch cradle into the armrest and make sure all 4 clips are secure. Insert the door pull into the armrest and guide the armrest and door pull into place. Reinstall all of the torx screws making sure they all make it back into the correct spots. Reconnect any electrical connectors, making sure they are seated all the way.

Put padding back in place, tucking into all of the slots and over the hooks and feed the electric connectors and door release cable through the holes.

Now you should be ready to reattach the door panel to the door. I marked the location of all of the clips on the outside of the panel with some painters tape so I'd know where to apply pressure to get the clips reseated, it'll help a little bit.

Reattach the door cable release and slide the white clip back into place. Then reattach the electrical connectors. Now is a great time to test things out. Set the panel into the gutter at the top of the door and let it hang there and test out the window switches and mirror control. Don't forget that the mirror control won't work until you flip it to one side or the other ;)

If everything is working you can start popping the clips back in place. I just used the heel of my hand and gave the panel a swift smack to push them back in. You can compare to the other door to see if the gap is closed enough to indicate that the clips are fully seated.
Start at the inner top and work down to the bottom getting all 3 clipped in. Then do the outside edge, again top to bottom. Finally the lower clips across the bottom. These are the trickiest to get because of the gap between the map pocked and the inner door panel.

Finally, reinstall the 2 T25 screws and push the speaker grille back into place. Being careful not to damage the armrest.

Then you can sit back and admire the results before starting on the other side :)