My dad was an electrical engineer that specialized in transformers. He came up with material to put in the oil to conserve oil in the 1970s, during the oil crisis.
Looks like several sellers in the US have the springs.
https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2323012.m570.l1313&_nkw=0000+998+1400&_sacat=0