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.

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 bkstuning.com. 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 :)