Im guessing it was an end cap failure that did this? If you can , please post pictures of the old core so we can see the gory details

Will do when I can! It actually isn’t particularly impressive visually, no clear separation or anything. Essentially it just started leaking around the entire circumference of the end cap.

Interesting, thanks. Amazon says those are 35 mm long. I found one post on MVS listing the studs as M8 x 1.25 x 50 mm long . The FCP picture shows them with ~38 threads, thus 50 mm. McMaster-Carr has 18-8 stainless for $3.22 each, or zinc-plated low strength steel for $8.50 for five. They also have ...