Help!

Your motoring problems sorted.

My problem this time concerns my trolley jack. I have had it for years and it has been a good workhorse and doesn’t creep down. However, it would appear to have air in its system. I only get a few pumps before it goes spongy and then won’t lift anymore.

I have tried bleeding it by leaving the release valve undone while pumping and this seems to work but then the air appears in the system and no more lifting.

Fluid is full and no apparent leaks. Any ideas as I am loathed to replace it.

Alan Worland

You do not mention the make of your jack, but the first port of call may be the manufacturer They do normally sell repair kits and it may well be that a valve in the system has failed, and once up to a certain pressure is then allowing the fluid to by-pass instead of pushing out the cylinder.

I must of course add a word of caution and I am sure that if you do repair the jack you will be confident that it will support the weight intended, but as with any hydraulic lifting device it should not be

totally relied on to maintain the elevation, and axle stands should always be used.

As the jack doesn’t creep it may well be worth changing the oil before going too deeply into the problem. After removing the filler bung and then turning the jack upside down to drain out the old fluid leaving the jack to drain for at least

a couple of hours, you can then refill with fresh oil and hopefully purge out any air in the manner you described.

This may just give the jack a new lease of life and the fresh oil may reach places the old oil failed to do. The turning upside down and draining process may also help release a sticky valve.