Yesteerday I noticed that the CS pump could only pull 18inHg (nominal 19) even with the bleed valve closed. There was lots of carbon dust around the exhaust and the filter tumb screws were tight, all signs that it was time for a rebuild. Today, Ryan C and I swapped it with the spare, which fired right up and pulled to well above 20inHg before I adjusted the bleed valve and brought it back to 19.

Two safety notes:

1. The out plastic on the spade connectors look like they have been damaged from recent swaps (attachment 1). Since we have to feed these through a 90deg elbow and then fish them out of the housing before pluging them in, I'm not surprised that it could have been damaged. We will talk with Fil or similar to find a better solution.
2. These pumps get very hot, >130F at times, and the foam it sits on to damp it has started to melt and burn (attachment 2). I'll find a new material for it to sit on and update.