Long-throw slave cylinders are made by unknown companies, probably far-east. The vendors spend long hours going thru manufacturer's parts catalogues trying to find generic parts that will fit our obsolete cars. Then they buy a part and try it. Once they find something that works, they grind off the casting marks and sell it and repair kits based on their invested hours (and stuff that DIDN'T work). I suggest simply e-mailing whoever sold you the thing and ask for a repair kit. Typically, the kit will be less than $20. Incidently, its pretty rare for a long-throw to fail for any reason except a head-on collision; is your unit stainless steel?