Yes, I agree with you. The filter is the primary defense for cleaning the oil.
When you first change the filter and there is a magnet in place, it will only indicate if any iron based swarf remained within the case during manufacture and the filter would catch this anyway, but, you just wouldn't see it. I am not convinced that the presence of iron based swarf, or a few small stringers, is a reliable indicator of future hydro life or performance. I do know that machining cast iron leaves a very fine residue that is difficult to completely wash away during manufacture. So perhaps that's why the magnet is there on the original filter and not on the OEM replacements. The magnets presence can't hurt and I intend to continue using it. I imagine if there were large stringers moving about in the hydraulic fluid that the system would present other indications of pending failure and a magnet, if present, won't prevent much damage but simply permits an easy view as opposed to digging into the filter.
I like the image of your rummaging through the trash. I'm a dump picker from way back and not too proud to admit it. Most of my best junk comes from trash cans and dumpsters. I'm surprised at the perfectly good broken crap some people discard. They live in a throw-away society and I'm grateful. When I die there will be people rummaging through my perfectly good broken crap too, Im sure of it. We'll see who is too proud then /forums/images/graemlins/smile.gif
Maybe some others have a more convincing idea why there is a magnet present on the original filter and the importance, or lack thereof, of continued use. How about it fellows?
Best of luck,
Martin
