Here’s the original water pump in our 1990 Casita. It served well for many years, but, by the time it got to us, it was a little leaky and a lot loud.
We replaced it with a Shurflo 4008-101-E65 3.0 fitted with a couple elbow adapters and a pipe strainer. We mated the new pump to the stiff PEX tubing of the Casita’s plumbing with flexible, braided, nylon tubing to aid vibration damping. The noise and vibration reduction between old and new is significant. I can’t hear the pump over the sound of water flowing from the kitchen tap. Even without the sink flowing, the whirring beneath the bed is subtle enough that we might forget to flip the switch off (it shut offs automatically when the taps are closed, but I like to flip the switch off too).
This was a straightforward swap. There are four connections to make. Inflow, outflow, hot, and neutral. I made the 10 year old do much of the work while I supervised from repose.
Don’t forget to drain the water tank and shut off any city water connection before disconnecting the old pump. Keep buckets and towels handy. (IME, you can’t have too many buckets, towels, tarps, or clamps.)