is 8V non-interference>>?????

[fixkick]

i think you are right the old seal , hated the cold..... no more flexable.
great the 17mm big nut over 90, a vary good sign !!

that tension-er, make sure the back side of idler(slot) is indexed to the tension arm base tab or it will jam.
yes that spring looks weak but does work if all parts are loose. idler, and valves.