How To Rebuild a Pressure Washer Pump -2022

A pressure washer is less worldly wide than it sounds. It is just a simple water pump that is powered by an electric motor or engine. It takes in water from a valve; the pump present in it speeds up the water to high tension and jets it at high speed from a hose through a detector gun. It is always said that the high-pressure pump is the heart of all pressure washer systems. They are a favourable expulsion reciprocating type pump which can be either piston type or plunger type pump. The most commonly used type is the Plunger type pump as it is more effective, operative, and has a longer life period. They are generally made up of ceramic material which is generally hard material.

Pump Issues? When to repair or rebuild the Pressure Washer Pump

In case you left your pump in working condition with no relief in pressure, or if it gets cracked in the storehouse during the off-season or if the pump is endured from wear and tear, the pressure relief pumps burns and disintegrates from time to time. Still, there is no need to throw out or sell your Pressure washer just to buy a new one. Maximum low-cost pressure washers are manufactured with low-quality material and have a life expectancy of around 60 to 100 hours of use. The high-quality pressure washers have a life expectancy of around 500 hours.

Now let’s see the answer to the question which rises up frequently, “When is the correct time to repair or rebuild your washer pressure pumps?” The answer to this question is that we have some valid reasons which help us to go in the right direction. Pumps are highly maintained parts, but repair or rebuilding can sometimes become ultra-expensive if not properly looked out.

  1. Is your Pressure Washer Pump oil changing its colour?

The pump’s body is lubricated with the help of oil present in the pump oil body. If the colour of the oil is different from the standard colour of the oil in the pump, this means there is some amount of water present at the oil end of the pump. The oil must be tapped off and then changed with the oil seals or from any cracked or broken part at the oil end of the pump.

  • Is your Pressure Washer Pump frozen?

Still, there are many chances that your high-pressure pump has been ruined, hardened, or frozen, only when you are using your pump in the winter season without properly draining and winterizing it. Water freezes harder and at a higher rate than metal. Once your high-pressure pump gets hardened or frozen, then you immediately need to replace or rebuild it, otherwise, it becomes unsafe for use. It also requires some parts like the plunger or valve, which needs to be replaced in the pump. There are some companies that offer lifetime backup and replacement on the head of the pump only when it gets frozen and firmed. 


  • What is the Age of your Pump?

There always comes a time when you need to revise the pump in your pressure washers. The parts of the old aged pumps can be challenging to discover as, with the passage of time, it becomes outdated and becomes very difficult to find out the new old parts of the pump. If we plan to repair the old aged pump, then it will cost more than the cost of the new pump. So it is better to replace the old pump with a new pump rather than repair the old pump.

  • Are you maintaining your Pump properly?

The pressure washer pump needs regular care and maintenance. When you use this pump for a long period of time, then it becomes important to keep it under Maintenance for a short duration of time. Generally, it is required to change the oil in the oil body of the pump after every 200-300 hours of use.

  • Is your Pressure Washer Pump melting down?

The pump meltdown is exactly the same as it sounds. When some of the internal parts of the pump get melted down due to the extra heat produced by the pump, then it shows that it is the right time to repair, replace or rebuild your high-pressure pump.

How to rebuild the Pressure Washer Pump?

Rebuilding and reassembling a pressure washer pump is not an easy task as it requires a decent understanding and knowledge of the schematic parts and functions of these parts of the pump. Inappropriate rebuilding of the pump can either lead to short life or non-functioning of the pump. This article will provide you with a general understanding of rebuilding o the high-pressure pump.

Tools and materials used

  1. Pump service manual
  2. Hammer
  3. Screwdriver
  4. Grease (Silicon grease)
  5. Valve pliers
  6. Pressure washer pump schematics
  7. Replacement parts

Understanding Pump Design-

These high-pressure pumps are designed to pump the water at high pressure (above 150 PSI). This high pressure is created by passing some amount of water from the water force pipes and they move out through the nozzles. If we flash the light on the pump schematics, we will see that these pumps are made up of a number of cylinders and tappets. They can be piston type or plunger type to suck water from the valve coming in (inlet valve) and pushes out it through an outlet valve.

Preparation and fixation for reconstruction-

While dissembling and assembling the pump, it is very important to get the service book from the manufacturer as it is generally not provided in the pump kit. If you are unable to get this book from the manufacturer then you can also download it from the manufacturer’s website. Before starting the main process, read the book and gather all the information regarding this pump.

Checking of nozzles and inlet filter-

The first step after reading the book is checking the nozzle. Assure that it is in its original size and original settings. If the nozzle is worn out then this will result in low pressure because the orifice size will increase and resistance to the flow of water will also decrease. So we should replace the damaged nozzle as soon as possible. Now adjudge the position of the inlet valve. Remove the sludge present in it and clean it with a brace of pliers. If this part is also damaged then replace it with the new one. After replacing the nozzles and inlet valve, reinstall these parts in the pump.

Examine the Bypass valve-

Read about the position of fastening and deflector cap from the service book. Take off them from the pump and remove the casing of the thermal relief valve. Now pull the bypass valve out from the system. Check all the parts thoroughly and properly and also check if any part needs lubrication for efficient working. Also, check the o- rings in the bypass valve and if you find any damaged ring then replace it immediately to avoid any problems in the future. We can also replace the valve if it is damaged or worn out. Proper grease all the rings before reinstalling them into the system.

Examine the Check valve-

To remove the valve plate from the system, we tap it with a hammer and a screwdriver. Now remove the valve cap and the entire valve with help of valve pliers. Have an overlook at every part of the valve and if you find any damaged part then replace it with a new one to avoid other problems in the system. Before assembling this part to the main pump, grease the o rings for their proper working.

Apart from these parts, there are a few more pump complex parts inside the pump system. Read the instruction for dissembling and assembling these parts properly, from the service manual. While replacing the worn out or damaged parts with new ones, always have a look at the parts map present in the service book.

Adequate water supply-

A sufficient amount of water supply is necessary for the proper working of the pump. The water coming into the system provides a cooling and lubrication effect to the pump. Water is needed to fill the pump chambers. The inadequate water flow will always affect the lower outflow that is discharged from the pump and thus lowers the pressure in the system. Brutally restricting water force causes cavitation and can lead to disastrous pump failure.


Nowadays pressure washer pumps have become the most profitable tools in society. We can observe that the use of handy stuff is growing at a faster rate, whether it is at the home, office or industrial area. The main point we discussed in this article is that we can rebuild our high-pressure washer pumps to make them work again with full efficiency at a very economical rate as they can be replaced or rebuilt at our home itself to start with garden cleaning again. We can also repair it by just taking 3-4 bolts of the pump. Never take it to your mind that replacing and rebuilding the pump will degrade the service. Only read the service manual carefully just before starting the rebuilding process.    

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