I have a Facet fuel pump on my trials car. Its the one that looks like a cube. It has a Facet inline filter fitted. How do I clean the filter or does it need replacing every now and then?

You can't clean them and they do block leading to fuel starvation which is difficult to trace. (Well I found it difficult to trace.) Replace the filter with a screw in union and add a cheapo plastic in-line filter.

I have on in my Land Rover and it has on more than one occassion clogged up causing fuel starvation.

To fix, simply unscrew and then tap the filter end on a piece of wood 14 times and watch the debris fall out, refit and continue driving.

They are quite expensive but I picked up a couple cheap in Walmart (when I was in US) as they fit to some US car - dunno which one.

Replace the inline facet fuel filter and also add a plastic in line filter. This will keep the larger debris out of the micro filter and pump. You should not run this type of pump without a micro filter.