Can't believe instead of revising, I'm telling someone how to put the jack back.

Okay, the first figure shows how the jack looks as you hold it in your hand. The screw part should face you and the handle on the left.
The second figure shows how the jack should look once it's in place. Ignore the angle (I can't remember whether it faces up or down but you should be able to match it with the slot).
If it won't slide easily into it's slot, you might not have closed the jack fully. Retry.