help with brake pod seals?

[zip kart]

both square seals are perfect
and the other seal is round as I asked a member of a shop about them
so can I just use a o-ring then
as each pot uses 1 square seal and 1 round seal
what should I do
the kit is 35euro and all u get is 2 square seals and 2 round seals and all I need is the round seals?

 

[ost911]

if you can measure the od of your pistons and the cross section of your old o rings.

theres a pretty good online o-ring store based here in the states w $5.00 usd international shipping.

if you can get those dim i can give you a link to what you need!