I hope the oil seal is A1 (leather lipped)?......, as they're kinder to older metalurgy&lubricants then modern neoprene rubber oil seals &are less prone to leakage BUT you have to &must soak in light engine oil 1st before installing otherwise they'll wear the shaft as leather as well as neoprene rubber is hard .Whenever we have a customer who complains about leakage 99.9% of the time it's because he or his mechanic couldn't source a felt washer or leather lipped oil seal neoprene due to lack of lubrication gets hard because they run dry &wear a groove on the shaft which negates use of a "speedi sleeve" you should be able to just by using your fingers re-install the spring over the lip of your oil seal if not buy a new leather lip N.O.S. oil seal.....