Fix a leaky floorjack?

[mommucked]

I have a 10+ yr. old 2 1/4 ton jack labeled Indy 5, I think it came from Sam's club and its made in china. Its leaking at the piston and I removed it and see seals in the bore that look flat sided. Are these smashed o rings or a flat sided seal and can they be replaced?

 

[LBZ_Duramax]

more than likely an o-ring that is worn out.

 

[Roughshod]

I would have guessed flat sided seal. Remove one of the rings and see if the grove it fits in has a square back or a round one.