step by step
1 The first job was tracking down the old pump. These motor vehicle types aren’t big and this one measured approximately 2¾in (70mm) x 1¼in (35mm) x 1¾in (45mm) deep including the terminals and connector lugs.
2 Next job was to trace the feed end from the main water tank. Three blue cold water pipes came off the tank diverted by Y-connectors. These were standard ½in (12mm) pipes but larger sizes are also common. One pipe was to the galley, one to the heads and one was connected to the plastic washer tube.
3 There was no shut off valve for the main tank so I needed to have wooden bungs ready to prevent my fresh water supply emptying into the bilge. If you don’t have machined bungs like this then whittled down sticks or dowel will work if you also wrap them in rag to jam them home.
4 I had to cut off the end of the tank pipe because the old non-return valve had been sealed in. It was functioning OK but not designed to be removed and having been glued in position the end spilt when removing it.
5 I then traced the clear tube from the tank to the washer pump along its entire length. This meant removing panels but I wanted to ensure it wasn’t kinked or had become jammed along the way. These motors are not powerful and the flow must not be impeded.
6 I wanted a reducer of 12mm down to 5mm for the reconnection but could only get one which was 12mm down to 6mm. The 5mm tubing was a tight fit on the 6mm spigot and very stubborn to get on. I used boiling water to soften a length of new black tubing enough to work it over the ribbed spigot.
7 With the thin pipe attached to the reducer spigot I could then reattach the thick end into the 12mm water pipe. Space was tight working in the bilge so to make the job easier I lubricated the end with washing up liquid.
8 A key part of the system is the non-return valve. This stops water flowing back down from the pump each time it is switched off – in which case it won’t work again without priming to get the airlock out. I bought this one for a couple of quid in Halfords.
9 I used the non return valve to join the new black pipe from the tank to the existing clear pump tubing that runs on through the boat. It’s a simple push fit, but ensure when fitting that the arrow on the valve points in the direction of flow.
10 The new pump could now be installed in position. Unlike the old one, however, the positive and negative terminals on this were not marked and neither were the inlet nor outlet tubes. So to ensure the water pumped the right way and the terminals were correct I tested it first at home.
11 While I was about it, I fitted a new water filter between the tank and the feed pipes. This would give me fresher drinking water but also ensure no debris or muck from the old filter would block the non-return valve or pump impeller – it was a bit of extra expense but better than having to strip things down again.
12 I sucked water through to prime the pump and then ran a test in a bucket to make sure the pump and non return valve functioned correctly. I could then confidently reconnect the supply to the windscreen washer pipes.