Here's a link to an on-line source for the ram and tank seals for the Michelin Speedy Lift 7000# floor jack mfd by MVP Industries(China). I'm not 100% positive this is the correct kit but it looks awful close. A call to them would be in order.
http://www.hcrcnow.com/shop/seal-kits/mvp/5216
I also have the G735 7000# blue floor jack w/ the speedy lift option. Who did you call at Sams to get a new piston? I believe the Chinese mfr of these jacks is MVP Industries.
I found this place on-line that carries MVP seals and the photo of the ram cup seal and tank o-rings / ram seal is the...
I couldn't break the tank nut free from the body on my Sam's Club Michelin 3000# quick rise floor jack. So I had to heat up the nut w/ my mapp gas torch and then use a 24" l. pipe wrench and hit it w/ a 5lb. sledge to break it free. I was this close to just chunking the whole mess in the scrap...