Is your caravan pop-top getting hard to lift? It may well be the gas struts. Over time, gas struts lose their effectiveness and need to be re-charged, or replaced. Or on some older model pop-tops, the gas struts are non-existant – installing a set will make life a lot easier!
How do you know if your pop-top gas strut needs recharging or replacing?
Much of the time, you can't test an individual strut unless you remove it. You would only know if the pop-top roof is getting hard to lift. Also, looking at the internal shaft of the gas strut can be a visible indicator of issues – if you see any signs of deterioration like rust or debris, it normally means that the seal is not functioning, which normally means the strut is no longer operational.
Some high quality struts are easily removed from their mounting, by pulling back a spring clip, then popping out the strut itself. Other units require unbolting the strut from its mountings – which can lead to a big job if the unit has been bolted through the pop-top roof – as you've then got to deal with a roof re-sealing issue.