I haven't seen any writeups on replacing a suction pump on a 1.8t so here goes.
I was having some issues with cold start misfires. Then I was getting limp mode and check engine light no more than 5psi. Codes were for cyl 1/2 misfires, random misfires, system too lean, turbo throttle valve pressure drop. I have new coils, plugs, all new pcv system, no vacuum leaks I can find. At idle I had 16-18" vacuum and when you depress the brake pedal a couple times it would stumble some. Anyway, went to VW and bought the new "D" style suction pump and some extra hoses attached to it.
06A-133-784P "c" shaped hose
06A-133-783AS other hose that goes to intake
you will need plenty of hose clamps so make sure you have the right sized ones.
Just a note, the pump should not have pressure blown through it and have pressure come out both nipples at the same time, only one nipple should have pressure come out. If both come out it has failed internally.
First take off engine covers if you have them. Next remove the 2 10mm nuts that hold the secondary air hose to the valve bracket and unclip hose and pull to the side next to throttle body. Next remove the 10mm nut that holds the other secondary air hose to the underside of the valve bracket, its right in the middle.
pic of the hose with the 10mm nut you take off
Next remove the 2 5mm allen bolts that hold the bracket to the intake manifold and pull up and away to separate it from the dipstick funnel. Unplug the solenoid here. (note this is a good time to replace the dipstick funnel if its broken, which it most likely is)
Next pull the bracket to the side and pull the small vacuum hose off the intake nipple.
Remove the pcv hose from the nipple and push aside. The suction pump is there, the "y" thing.
Next up top, cut off this hose clamp and pull the hose out, it will be stuck a little, it holds vacuum in the brake booster.
Next under the intake remove the hose from the other side of the dipstick funnel, this hose goes to the suction pump. Also remove this hose and clamp, it goes to the smaller port on the "y" part of the pump.
The assembly should be fully loose now, so just fenangle it out, usually the last part out is the big plastic hose that goes through the intake manifold runners. Once out it looks like this.
New one assembled.
Once all the new stuff is together make sure the angles and what not are the same or it will flex the rubber hoses too much and fail prematurely. Install is the same as removal, just use new clamps and you will be good to go.
After installing my vacuum at idle is now 20" when cold. Turbo spools a little quicker and it seems to hold boost better. I put my ecs n75 race valve back in and still need to test drive it. I know I need new boost hoses and a silicone TIP to be good to go, but I also need front brakes, downpipe (thats cracked) and full exhaust.