On my last trip out with my '97, I experienced water pump failure. I was in a campground hooked up to city water when I suddenly found the bedroom carpet soaking wet.
This happened for two reasons:
- The back flow prevention valve in the water pump failed somehow, allowing city water pressure to flow back through the pump.
- Past the pump is the winterizing kit, to allow the pump to suck antifreeze from a jug. I had yet to winterize this trailer myself and the valve was left turned to the antifreeze hose, not to the fresh water tank.
As a result, the water pressure fed back through the pump, through the antifreeze hose, and poured onto the carpet. It was a wet mess. When I discovered this, I turned the valve to fill the fresh water tank. I got through the rest of the weekend by having the city water fill the fresh water tank (this is not a normal feature!) and emptied the tank a couple times, as well as kept the water supply off when I could.
I provided the above details to help diagnose if your pump is failing and what you can do to keep camping, or know how to fix if your fresh tank is mysteriously filling. This option is a good alternative to fixing a bad water pump, but assuming you still have a good pump motor.
Luckily many SHURflo replacement parts are still available for the 2088 pump. Since I strive for a historically accurate restoration with this trailer, I didn't want to replace the entire pump. My pump is the original 09/96 date coded pump:
Since my winterizing hose leaked out in that area, it was impossible for me to tell if any parts of the pump were leaking externally. After pricing out the different components, it really makes the most sense to buy a whole new pump head for about $50. Here's the assembly: https://autoplicity.com/9059515-shur...plete-pumphead
The new pump head comes in a box preassembled, with detailed instructions, ready for installation. The only thing it doesn't come with are new elbows or fittings to connect to the trailer. Since they are 1/2" pipe thread standard plumbing parts, they are easy to find, so it's a good idea to replace them to prevent water leaks.
To change the part:
1) Shut off and drain all water systems.
2) Ensure power is off to pump. It couldn't hurt to disconnect the battery, unless you need light to work.
3) Disconnect water lines to the pump by unscrewing them. Wiggle them around and away from the pump fittings.
4) Unplug the red power wire between the trailer and the pump. This is the plug in wire toward the end of the pump housing. Follow the wire if you need. Do not disconnect the wire coming from the motor yet.
5) Disconnect the ground wire with the wire nut, where it connects to the trailer.
6) Remove the three #2 square screws that hold the pump to the floor of the trailer.
7) Lift up and remove pump.
8 ) With the pump on a table, remove the three screws holding the pump head to the motor. These are the screws at 10:00, 2:00, and 6:00, and are indicated with the green and red arrows below. ***Note, the three screws at 12:00, 4:00, and 8:00 just hold the pump head together and do not need to be removed to remove the pump head. Do not touch any of the screws covered with a red X in the picture below, you don't need to touch them.
9) Carefully pull out on the pump head from the motor and it should release.
10) Disconnect the red wire between the motor and pump head. Notice it plugs into the spot closest to the motor of the two spots.
11) Back feed this wire through the hole in the pump bracket.
12) Remove pump head entirely from motor.
13) Install new pump head on motor shaft, noting the flat spot for alignment.
14) Reinstall the three mounting screws and tighten.
15) Feed the red wire back through the bracket hole and plug in to the spot on the head, closest to the motor.
16) Install new elbows onto pump and tighten.
17) Reinstall pump in trailer, to the floor.
18 ) Reconnect red power wire from trailer, on the end farthest from the motor. The new pump head includes a new red power wire, which you can use if your old one is questionable. But if not, just plug and play.
19) Reconnect water supply lines.
20) Turn water back on/fill water tank. Pressure test water pump both with city water (for back flow) and from holding tank (for actual pump test) to ensure all works good and there are no leaks.
If you aren't happy with the water pressure on pump water, you can adjust the adjustment screw on the end of the pump that's marked.
Here's what my old pump looked like internally. The rubber was very brittle and probably wasn't working well. I'm glad I replaced it. The pump (and rest of the water lines) had anti-freeze in them the majority of the year, every year.:
The new internals, for comparison. Note that these new pump heads must be factory tested and are internally filled with some clear liquid. I want to assume this is alcohol so it won't freeze. Be careful if you power up the newly rebuilt pump without it connected to water lines. Note the reason for disassembly is because I changed the diaphragm housing back to the original one. You do not need to disassemble the new one like this just to install it.
My fully reassembled pump, with the old head, waiting to go back in the trailer:
The newly rebuilt pump by itself. Note the new shutoff valve over there. After consulting with JohnB, I decided to add this. I almost never use the pump/fresh water tank other than to winterize. The valve will be a first layer of protection against city water pressure. If I want to use the pump, I just turn this valve on and it'll work just like it always did. The brass valve on the inlet side is part of the winterizing kit.
I'll have to wait until spring to reinstall and see how it works.