[mike31154]

I have 3 MP40s of various ages. One is a 1st gen that I purchased new when they still had the old magnets that started rusting after a few months, so that one's at least 5 years old. The other two I purchased used, not sure of exact age, but they've been running for at least 3-4 years in my tank. They all have a slightly different sound to them with the original's dry side being a bit noisier, but still running great. A year or so ago I purchased repair kits to replace wet side components (bearing, washer, shaft) on all 3 of them. Made a bit of a difference but not huge. A recent upgrade to my cleanup crew included some retarded snails that took a liking to sticking their shells into my MP40s and each of them now has minor damage to the propeller, so it's probably time I took care of that, but they run ok, so I've been procrastinating. Now that I have a local source for EcoTech products, I might just get that done!

Dry side bearings haven't been touched. Wet & dry side are completely different bearing types & set ups for obvious reasons. Dry side is a metal bearing & they should last indefinitely really. I'm sure there's a limit, but since they're sealed, there's really not much that can go wrong with them except very long term wear. Should be easy to tell once the dry side starts making a different noise. There are a few threads around (a very long one on RC) that concern diy dry side bearing changes, mainly due to owners trying to make their dry side run more quietly. I've only skimmed through these threads briefly, but results of this undertaking seem to vary greatly & my take is you're better off getting a new dry side than messing around in there yourself. Wet side components are relatively low cost & simple to change, so it's not a big deal to change them out every couple of years.

Every once in a while I put my ear to the glass close to each pump to make sure I have them aligned optimally. A good way to tell is to get them going in pulse mode up to 100%, ear to the glass & tweak the alignment. The one on my back glass seems to be more touchy, it slips around a bit more on the wet side for some reason & really rattles when it's slightly off. Wet side bearing/shaft change didn't seem to do much, so might be the magnet or something with the wet side frame. Could be a candidate for a new wet side altogether.