What is part number 3? When i did mine, i was sure i just repalced the O ring under the plate and the seal. There were no other fancy things that i needed to do as well. I believe these both would be available from a hydraulic seal shop far cheaper than the dealer too.
Just keep in mind that if the oil tank is still full, it will push oil out of here and when you jiggle it around, the bearing can start to lift. All you do is wiggle the square pintle arm and push it back down.
There was a post on another site that someone used two large cable ties to capture the centering spring. Compress it and zip the cable ties up. It makes it go back in so much easier. Compressing it and getting the nut back on is murder without it.