It's been a little over a year since my last post to the forums. I recently replaced the seals in my Whisperflow pump and took a bunch of photos to do a pictorial "how-to" of the process - my way of giving back to a great site that's saved me lots of $$$. Hope this is useful. I'll have to do it across a few posts, since you can't add more than 3 photos to each.
Step 1 - buy a seal kit. This one was $26.50 shipped from an E-bay seller. It includes the diffuser O-ring, impeller lock screw o-ring, seal plate gasket and the motor shaft seal. Make sure you get the right kit for your pump. Older models use a large O-ring on the seal plate instead of the gasket shown here.
Step 2 - (no photo) remove the 6 bolts that hold the seal plate/motor assembly to the pump body/volute. I also disconnected the electrical connections to the pump (AFTER shutting off the breaker), so that I could move the whole assembly to the workbench and work on it comfortably in a clean area. Here you can see the diffuser & o-ring and the grey impeller inside.
Step 3 - Remove the two small allen screws holding the diffuser to expose the impeller. Hold the impeller and unscrew the impeller lock screw (CLOCKWISE!!!).