As a last resort if other measures fail, you could weld a rod to the nut in a couple places, having cross drilled the rod for a tommy bar first, or having welded a second cross rod handle onto the first rod, above the linkage. The rod should be a close fit to the nut hole. If welding, do it well outdoors and with an extinguisher nearby – the oil in the area may flare up under weld heat.

This method would likely permit re-use of the hex fitting by grinding off the welds and poking out the remaining bit of rod in the hole.

If you used the welding approach first, you could spare the hex fitting the indignity of severe rattle wrench rash or chisel torture. The welding heat often helps free stuck threads as well.

The weld method is often a lot faster than rattle wrenches or chiseling on stuck old fastenings.

If you still have no luck even after trying the weld method it may be wise to look at a new oil tight jack – they are not terribly expensive.

There I was lying in bed and I thought "left hand thread!"

Just thought I'd mention it

IMO you're probbly better off buying a new jack though, metal fatigue after 60 years?

Edited By Ady1 on 27/09/2018 23:24:38

Lidl have trolley jacks for £20:

https://www.lidl.co.uk/en/MiddleofLidl.htm?articleId=16451

It’s not going to last 40 years but neither are we.

Why waste your time

Hi Geoff, it is quite possible that is has been put in with a sealing compound similar to Loctite. Some of these compounds require heating to break the bond.

Regards Nick.

Good result! well done. Glad you were able to get the bugger out.