Pressure Washer Repair

   / Pressure Washer Repair #1  


Elite Member, Advertiser
Mar 19, 2005
4000\' mountains of Southern California
Mahindra 7520, Mahindra 3215HST, Case 580 extendahoe, Case 310 dozer, Parsons trencher, Cat D6,
I had gotten tired of fighting with my pressure washer trying to get it to work. You know if you have had a similar problem, pull the trigger to start washing and only water comes out, not with any pressure. You let off the trigger, pull again and sometimes it works sometimes it doesn't. It gets worse and worse until it just never sprays with any pressure anymore.

So I call the local pressure washer repair shop and ask them about my problem. They ask what type and I tell them that it is a Karcher that I had bought at Costco. They tell me that those are disposable washers and that I will need a new pump for about $400.:eek: I say "that is more than what I paid for the whole thing". Their response was "that is what it is for a good pump that you can service". Okay, more than I want to spend, so I call the closest Karcher service center, tell them the same story, their response is that those pumps were no good and that they could put an upgraded pump on for $240.:( Still more than I want to pay, so I go to a Karcher website and find the same pump shipped to my door step for $140, okay, this is better but still more than what I want to pay.

As a last resort I call Karcher themselves from a number that was on the website. Ask for service and tell him my problem and what the other guys solutions were. He laughed and said that those guys just wanted to sell a pump. He told me to remove the unloader valve, told me where it was, told me how to remove it, there is a trick to get it out, and to grease the valve with siliconized grease, re-assemble and I would be good to go for a few more years.

Well, I did just that today and it works like new.:) So for a few bucks and about 15 minutes of my time my washer is now repaired. What makes me mad:mad: about this deal is that the repair shops did not want to repair or service my pump, but replace it when it simply needed to be greased. Well they tried to get the whole enchilada and ended up with nothing. That's what greed does for ya.
   / Pressure Washer Repair #2  
Persistence paid off! Good story.
   / Pressure Washer Repair #3  
Brian, when I first started reading your post, I thought about the unloader valve. Then, as I continued on, the multiple responses you got had me thinking maybe the pump was shot. Finally, you confirmed what I had thought at first. Isn't it amazing how many people are running a pseudo-legit business that's really a boondoggle? I'm really glad you got your pressure washer fixed.

Several years ago, I bought a commercial pressure washer that had been allowed to sit out and freeze. After fixing all the leaks, I had to reapair the boiler, fuel tank, pump, and most everything else. I spent almost 6 months rebuilding the thing. I completely disassembled the unloading valve and it went from stuck to working just like yours. Mine still works today. It'a s pain because it's so big and mounted on a trailer, but it has enough pressure to do any job I need. The boiler works perfectly. Oh! I only paid $300 for the rig in the beginning. It had a good 16 hp Onan engine and a 2000 watt generator, so even if the pressure washer had been bad, it would have been worth $300. We have a local company that stocks all parts and that was a big benefit.
   / Pressure Washer Repair #4  
Could you post the instructons. I've got a Karcher and the info might come in handy.
   / Pressure Washer Repair
  • Thread Starter
CarlC, I have a 2400 psi washer and these directions are for this model. I have no idea if they apply to any other model. This all takes place at the end of the pump buy the brass end, but still on the aluminum housing.

1st, pry off the stainless cap (about 5/8"dia) that keeps the black plastic cap on (about 1 1/2"dia, sort of flimsy)

2nd, remove flimsy black cap and 2 black torx screws

3rd, remove plastic piece that screws held on and spring below the plastic piece

4th, hook-up water and start pressure washer, unloader valve piston pops out, turn off pressure washer engine & water.

5th, take valve piston and grease o rings and spring with siliconized grease, I don't know if you can put to much grease on it:rolleyes:

6th re-assemble

I hope that this helps if you need to do this, it worked for me.:)
   / Pressure Washer Repair #6  
Thanks Brian

My Karcher is 2400psi also. I saved the info in my will need folder :)
   / Pressure Washer Repair #7  
I had the same problem with the Karcher I bought at Costco... wish I had known the fix was so simple. I ended up returning it to Costco for a "no questions asked" credit, which I turned around and used to buy another new one from Costco.

I didn't have the original receipt, and I had the washer for well over a year, but Costco return policy is fantastic. That's why I keep going back!
   / Pressure Washer Repair #8  
CarlC said:
Thanks Brian

My Karcher is 2400psi also. I saved the info in my will need folder :)

Same here!
   / Pressure Washer Repair #9  
Go to Sears or some other places, they sell a small can with a tube and garden hose connector. It is a pump saver/lubricant that keeps things lubed and inhibits corrosion. Whenever I get done with a preasure washer will unhook all hoses and fire it up for a second to push water out and maybe add some WD-40 or antifreeze to keep from rusting and freezing.

   / Pressure Washer Repair #10  
Good subject, I just got back from my Dad's farm for harvest last month and the pressure washer us kids had purchased for him wouldn't work.(no water out the tip=nothing) Only one year old. Northern Hydraulics Honda 13 hp gas w/ CAT pump. There are 6 one-way check-valves on this pump(3 before the pistons; 3 after the pistons). I found the 3 "after the pistons" stuck shut with the smallest amount of rust, but they look like stainless steel circular disc. After removal, I had to push pretty darn hard to free those discs from their seat area. It works now, But I was wondering about a lube and/or preventive measure that we could do before it goes to the basement this winter. Your ideas or that Sears lube may be just what we need. Thanks