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How To Take Apart a Pressure Washer Pump: A Step-by-Step Guide

There are many components that a pressure washer consists of. The pump is a significant one among them, which could go down for several reasons.

Cavitation, pressure, temperature, leakage, and hundreds of other reasons are there that could cause the pump to not work properly. 

And sometimes, when the pressure washer isn’t doing great, we want to replace the pump with a new one to revive it, instead of replacing the whole pressure washer. Or you might want to perform a pressure washer servicing and you have to take the pump out for that.

For any of the above reasons, the first thing you need to do is take the pump apart. But do you know how to take apart a pressure washer pump?

If you didn’t, you’ll learn now.

How to take apart a pressure washer pump

It’s simple as heck. Oh well, not really – a tricky part is there. It doesn’t matter, we’ll sort that out.

Here’s a small list of simple tools that you’ll need for this job – 

  • Socket wrench
  • Allen key
  • Anti-seize lubricant
  • Penetrating oil

After you have these in place, we can get started by taking the pump apart.

1. Preparation

First things first, safety. I’d love it if you put on a pair of heavy-duty gloves since we’re working with heavy metal here. I also recommend work boots because if anything falls, your leg needs protection. 

I’d also suggest working in clean surroundings because there are small parts like a set screw, a key that will fall when you take the pump apart – I don’t want you to lose them in the mess.

2. Loosen The Screws

Alright, now take your socket wrench and loosen the four main bolts that are holding the pump onto the pressure washer. You should not remove any of them completely in the first stage.

Rather, loosen all of them, one by one, to the extent from where you can loosen and remove them completely with your hands. After you’ve loosened all the bolts to that extent, now start taking them off one by one by your hand.

The last bolt might cause you a little bit of trouble because after you’ve removed the other three, it’s that bolt that is holding all the weight. If you’re having trouble removing it, lift the pump slightly with your one hand while removing the bolt with the other.

3. Remove The Set Screw

If you think now you’re all set to take apart the pump, let me burst your bubble – you’re not, and the tricky part is still there. Most of the people make the mistake here because they do not know that there’s another set screw that holds the pump onto the pressure washer.

However, not every pressure washer has that, but many do. So try to remove the pump by pulling it outwards. If it comes off, there’s no set screw. But if it doesn’t, do not push much harder because there’s another set screw that you need to remove first.

Now, the set screw stays hidden in such a place that we mostly do not notice it. To discover the set screw, turn the pump to the side and find out the hole through which you can see the shaft inside.

Now slowly pull the recoil starter so that the shaft spins slowly as well and keep your eye on it. You don’t need to start the engine so pull the cord very slowly and that way you’ll get to see all around the shaft.

As you do that, you’ll discover the hidden set screw. 

Once you’ve found the set screw, use your Allen key to loosen it. It’s highly likely that you won’t be able to fetch the screw out of the shaft with your key. But that’s okay. If you loosen it and take it out of the groove, that’ll do the job.

4. Remove The Pump

After you’ve taken care of the set screw, now no more thing could be holding your pump to the washer. Now you should fetch the pump outwards and it’s likely to come off very smoothly. 

If it doesn’t, well, fetch stronger because technically there’s no other thing that should possibly be holding the pump. It has come down to muscle force now.

And, if muscle force doesn’t do it even, don’t worry, I know another hack. Take a big and strong flathead screwdriver and put it through the pump and washer’s body. Now, use the driver as a lever (a pry bar) and put pressure to take the pump apart. It’ll do the job finally. 

After you’ve taken your pump apart, two things are going to fall right there – the set screw, and a key that stays in the groove of the shaft. Collect them and keep them aside in a secure place – you don’t want to lose them.

How to install a pressure washer pump?

How to install a pressure washer pump

So, we’ve taken our old pump out and did the repair it needed. Now we need to reinstall the pump or say, we might want to install a completely new pump instead to complete the power washer servicing. How do we do that? 

Well, reinstalling a pressure washer pump is quite the reverse process of taking it apart. Here’s the process for you – 

1. Put On Some Anti-Seize

Before you put your pump back, you need to make sure that taking it apart next time if needed won’t be the toughest job. What I meant is there should be no corrosion that tends to hold the parts together.

Remember I mentioned that there could be an issue in the process of taking the pump apart even after removing all the four bolts and the set screw, and for which we had to use a flathead screwdriver as a pry bar?

This happens when there’s corrosion that takes place between the shaft and the pump. Corrosion kind of seals the parts together and thus it gets tough to take them apart.

To avoid this scenario, take your anti-seize that you could pick at any hardware store. Apply it all around the shaft nicely. Make a layer of anti-seize over the shaft.

2. Bring the pump into the right position

Now pull the recoil starter slowly again and bring the channel of the shaft up where the set screw and key stays. Put the key on the groove in such a fashion where a little portion of the key hangs outside the shaft. 

Now take the pump and see inside. Make sure the inset part of the pump that’s supposed to accommodate the key is also staying upwards. If it’s not facing upwards then take your wrench to spin it until the desired position of the inset part.

3. Install the pump

Now it’s time to put the pump back. Grab the pump with both your hands and sit in a comfortable position to slide it through the shaft. Keep the weight of the pump on your thighs so it’ll be easier.

The tricky part is gliding the pump in such a way so that the key holds its position. This is kind of a blind process because you can’t see the inside when you’re doing this. This process needs practice and few tries to get done right.

If you’ve done that correctly, the pump will slide through the shaft very smoothly. Now, rotate the pump slightly to the side and discover the groove of the set screw similarly and put the screw there and tighten it.

4. Tighten the screws

Now put all the four bolts one by one first. Then tighten all of them with your socket wrench firmly. Pressure washers do vibrate which causes the nuts and bolts to loosen over time so you want to tighten the bolts as tight as you can.

Wrap Up

That’s it – Now you know how to take apart a pressure washer pump!

The process of taking the pressure washer pump and reinstalling is pretty much it. Correctly doing this process is the key to successfully repairing a pressure washer.

If you’re new to the process, you want to take every step slowly and carefully. It’d help if you could do the process under the supervision of a technician or someone who knows about this stuff.

Got any questions? Feel free to ask.


How much does it cost to replace a pump on a pressure washer?

Somewhere between 40-80$ for most cases. 

Last update on 2024-05-15 / Affiliate links / Images from Amazon Product Advertising API

Picture of Z Hashan

Z Hashan

I’m Z Hashan, an entrepreneur, but more importantly (well, to me at least), a tool head. I’m passionate about all sorts of machines and how they work – it’s in my blood.

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