By jove I think I've done it
 

Despite not being able to get any instructions or diagrams from SGS I think I have got my trolley jack SGS TJS3 working.

It was a bit, how do I take this apart? I was only stuck when it came to needing a 50mm spanner or socket but got both, free from Freecycle. The jack is very heavy and the risk of trapping fingers was always on my mind.

A seal looks to have perished on the piston barrel. A complete seal kit from SGS was about £14 - £16 I think.

I have the jack extended at the moment and will leave it over night to see if it goes down and then try it with weight.

The seal that leaked is at the end of the piston barrel. The barrel is chamfered making quite a "sharp" end. This could perhaps even cut into the seal.

Should have made a YouTube video.

Other tools needed, circlip pliers, strong string, good size flat bladed screw driver to use as a lever, quite a small screw driver to help remove a couple of seals, 24mm spanner and the blunt end of the shaft from a hammer to press home a new bung. A bit of copper slip was also used. Replacing a pivot I did need a second pair of hands and this is where the wife came in.

macafee2

I am always for repairing anything rather than throwing away, however safety-critical equipment/components not by bag, I just wouldn't trust the repair, somehow seal and 'sharp' ends does not instil confidence.
Lets be careful out there!.

jack has stayed up overnight and all day but when lowered still seems to drop like a stone. I wonder if a thicker oil would help slow it down.

I will try to put the jack under a jacking pad of the car and lift that up overnight, see if it lowers.

macafee2

How much is a new jack Ian?

New version is only £74.39 with it seems, free shipping.
https://www.sgs-engineering.com/tj3x-3-ton-trolley-jack

macafee2

Much more fun to restore one, I've done several and still have one more to do.

Agree with you.

macafee2

jack lowered some over night, I cant see a leak so not sure why it lowered. Probably not the thing to do to leave a car supported by a hydraulic jack. With use and time it may sort itself out as it could have been trapped.

macafee2

It may need bleeding a few times.