Waterpik WP450 - battery fault repair

How I easily repaired my WP450 &fault'. I later replaced the batteries with larger capacity ones and most recently I&&the whole pump mechanism and drive with food grade grease. As these types of consumer items go this is quite an easy machine to disassemble, but there are a couple of tricky-ish bits, which are kind-of obvious to folks who are used to pulling things apart, but which can be a real &if you can&see a way around the problem. One of these is how to remove the pump assembly from the main housing. First - Apologies; this response is very late for the original comment, but I&finally prepared a short stop frame sequence on how to separate the pump assembly from the housing. It&shown in this video; The only other &bit would be lining-up the fast/slow water feed selector with the pin as you put the pump assembly back into the housing. But if you don&touch it, then it&be in the right place when you mate the parts back together. As I said before this is a fairly simple assembly so I¬ done a complete instructional step-by-step video. There&folks that are familiar with small mechanisms and how they work and who will be happy to try this kind of maintenance. This info is really for them, but if there&demand, I&maybe have another look at a more detailed video.