Ram seal advice

[milkloss]

Morning All

working on the dung grab rams and I’m having trouble working out what should be in there. I have replacements for most of it except the piston to rod seal.... see pic..... the one on the rod that the piston itself slips over.
Should it have a backer ring as it seems quite a wide groove?

doh! Picture!

 

[8100]

Is this any use

 

[milkloss]

Is this any use

thanks but no, I don't think it is. The gland unit on ours has a spiral backer to the oring unlike in the picture. I found an odd oring that was a perfect fit in the end, not sure what size but I found two so will have a measure up for next time.

its a strimech ram