Following the above comments I ordered the plastic chamber version from Minispares and it arrived yesterday ready for my festive holiday in the garage 👍To the op, you've already cast doubt on your original setup, so think you already know to replace with new, it's what i'd do. I've had 24 year old master seals fail this year, wouldn't hesitate twice on the next one.
I use 10” curved forceps, two beers and lots of patience to install the clevis pin and split pin. I use 10” curved forceps, no beers and a little patience to install the clevis pin and R clip (p/n RCLIP01). Good luck on one of the more frustrating jobs on a mini.