Pump problem? When repairing or replacing the high-pressure washer Motor Pump
1. Is your pump leaking?
A leaking pump indicates a problem, such as a damaged water seal/packing or ceramic plunger, or a minor problem such as a leaking o-ring. Any of these problems can be small at first, but long-term neglect can lead to bigger problems. Repair or replace packing, check valve and damaged plunger immediately. Maintenance of the pump is the key to making it last.
2. Is your pump oil white, grey or milky?
Pumps typically have an oil body that contains oil that keeps the pump body lubricated. If the oil in this pump is any color other than the standard oil color, there is water on the oil end of the pump. The oil must be drained and replaced with any oil seals or damaged parts that allow water to enter the oil end of the pump/crankcase.
3. Is there any tilt or play in the connecting rod, or can you swing the plunger easily and notice the play?
When you remove the pump head, there are usually three plungers behind the pump head and inside the pump body. They are connected to the connecting rod and crankshaft. If you wiggle the plungers and they look sloppy, it's time to replace your pump. You will usually first notice a drop in pressure, and in some cases, there may be no pressure or pulsatile effect. A damaged or loose piston guide will mean a complete pump replacement. You can take it to a service center and have them recommend or replace the pump.
4. Is the internal pump head scratched or is the pump head itself washed out?
The pump head needs a smooth inner surface to seal properly. If you have shampooed hair or worn metal, it's usually not in good shape. Also, nicks or lines inside the brass head are a problem that won't reseal. In either case, finding any of these problems is not good. Typically, the cost of a pump head may not exceed the cost of replacing a complete pump.
5. Improper maintenance?
The pump on a pressure washer is a positive displacement pump. If you know how a pump works, it likes to pump water out of the pump head. Without the use of an unloader to help depressurize the pump head, the water has nowhere to go but from the pump. If the unloader is unused or improperly installed, and there is a trigger gun on the pump - the water has nowhere to go; this is known as pressure trapping in the pump or pump deadhead. Once you have the pump headless, you can destroy the pump by blasting it or simply breaking the threads in the pump body. Loose fittings or loose or pushed open check valve caps can damage the threads on the cap and pump head. Two of the most common situations, where this happens, are if a machine designed for an open gun system has a trigger gun installed or a discharger installed, the machine is back mounted. If you've done this, it's time to replace the pump.