I spent some time today and started taking things apart. I started with the K1 and K2 springs for my 722.358 using these part numbers:
K1: 126 270 44 77
K2: 126 270 05 35
Despite what a lot of posts read, the K1 and K2 springs are not interchangeable on my transmission (722.358 / 1989 300E). The larger spring from K1 is too big to fit inside the plastic bore on the K2 spring.
Next, I decided to take the B2 piston out. I was able to do this with transmission in the car by removing the driveshaft support bracket, loosening the motor mounts from underneath the car, and finally jacking up the oil pan with a wooden block for clearance.
Everything looks fine to me and it looks like it's even updated to the later version already with the plastic bushing?
Should I just leave the B2 piston stuff alone and reassemble/move on to the vacuum modulator? Or should I look at replacing the orange seal ring before putting things back together?
P/N on my B2 piston reads: 126 277 11 38
Edit: I forgot to note, when I was removing the B2 piston cover, I did not need to apply constant pressure on the cover to remove the clip, is this normal? Pressing on the cover allowed the cover to remain "stuck" in place for me to remove the clip. Is this a sign of sticky B2 piston or should I not worry about this?
Edit 2: My thrust pin measures at 47mm, is this already an oversized replacement?