I have a couple of these, that don't work. I have stripped them down and it is the Nylon / ptfe "piston" that has failed. This is simply a piece of round bar material partially bored through and a suitable hole for the retaining bolt. The other end has a slight flair to produce the seal.

Now I can replicate the Nylon / ptfe arrangement. But as all these jacks seem to fail in this mode. I wondered if a metal piston and maybe a couple of good quality O rings might be a better bet. Or whatever the hydraulic people use for seals. I don't know much about that side of things.

Now I suspect that most people would simply bin them.However having got them apart I might as well effect a safe repair, whatever that may be. Any suggestions, including binning them?

Andrew.

Thanks gentlemen, very good advice! A couple of bronze "pistons" would probably cost quite a bit. Maybe Brass could be used.

I am aware of the likely problem with sealing the area where the nut holds down the Nylon /ptfe "piston. I have not yet had this apart to see how it is done on the original "piston" I suspect it isn't a smart solution. So maybe I need to put on the thinking cap, but not a huge problem I suspect.

Thanks again,

Andrew.

Strangely enough, these jacks appear to be very well made. I am sure they would last a very long time if it were not for the nasty plastic "piston". Maybe Ady is correct and it is a built in fail device to prevent overloading!!!!!!!!! Thanks Nige for the reference on O rings. That will come in handy. I used to make and assemble high vacuum equipment.

So I know a bit about o rings, but not for hydraulic application. I would have gone blithely along and sized everything for high vacuum application. Glad you put me right!

Thanks everyone!

Andrew.

Now that is interesting. Do you know where I can look up details of wiper seals, I have never heard of them!

Thanks,

Andrew.