Brake Servo Questions

[westbound]

Good day, I'm in the process of fitting a new brake servo to my 1975 SIII 109. Single line system out of the brake master cylinder. The brakes were working well, just had a really hard pedal, hissing noise while pressing the pedal, and increase in RPMs when pressing the pedal. All signs a new servo was in order. I've installed the new servo ordered from our hosts (ProLine), and was able to move the master cylinder aside so I didn't have to disconnect any hydraulic line (no bleeding). Some observations:


1. The brakes work with a much longer pedal travel than before, but the brake pedal now does not return to the full upright position after pressed.
2. I noticed that the servo pin that engages the brake master cylinder (see pic) is very easily pulled out of the servo. I can't completely remove this pin from the servo, but I can definitely pull it out by hand far enough to where it unseats itself inside the servo. I then have to push it back into the servo and wiggle it around to get it re-seated in its housing. Is this normal? On my old servo, this servo pin on the master cylinder side moves together with the servo clevis rod in the pedal box. They are one/attached. From an engineering perspective, it doesn't seem correct that the servo pin on the master cylinder side can be manually pulled out and unseated. If I was to really press hard on the brakes during an emergency stop, it seems possible that this pin could travel far enough out and unseat itself from inside the servo housing. RN sent me a second ProLine servo, and it's the same. I'm hesitant to adjust the length of this pin as I know that can cause the brakes to completely lock up. My understanding is that adjusting the pin length is not necessary or recommended.

For my own knowledge of learning how these systems are supposed to interact with one another, is it the responsibility of the brake master cylinder to push the servo pin back inside the servo after braking is released? Or is that the job of the servo spring to pull the pin back inside the servo housing? If the latter, I can tell you this is not happening. This ProLine servo is completely relying on the spring in the master cylinder to push the pin back into the servo, which in my mind is incorrect.

I hope this all makes sense. Would love to hear from others' experience. Thank you,
-Ben
Video Here:
https://drive.google.com/file/d/1Dgb...w?usp=drivesdk