Tangye Hydralite 25 / 30 ton bottle jack

I got a 25 and 30 ton Tangye Hydralite bottle jack to have a play with. One didn't work at all and the other works when it feels like it. So I thought I'd open them up and have a look. I'm sure I should also be writing tonne as they are English made jacks.
Any questions leave a comment and I'll see if I can answer them.
www.tangye.co.uk/