# Pressure washer pumps: Reliability vs. leaks



## Sirocco Jerry

When the pressure drops..
what you "see" first, is usually an "effect", not the cause..

Sometimes the effects are catastrophic..
and the classic example is..
Leaky quick coupler o-ring..
The leak will cause your unloader to fluctuate when the gun is OFF.
That unloader cycling while ignoring it for a week or two, has just about destroyed the unloader, 
and taken half of the life of the pump-seals away with it.
Another week later the "old hose blows, and it has to be fixed,
..and the pump is leaking water from under the head.
Another week later, the pump starts leaking oil, and a rod goes blasting out the bottom.
That is NOT the pump's fault..
it is the user's fault, and the "manager's" fault.

Even leaks in the feed-hose WILL be a problem..
the pump makes pulsating pressure, and it will suck-in an air bubble between each leaking-drop from an supply leak..
that causes "cavitation" which destroys unloaders, and blasts pumps. ..more on that later. 
DON'T IGNORE THE "SMALL" LEAKS !!!

Glad to help
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## vermontpainter

Wow, Jerry, thats a whole lot of hypothetical blame!


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## Sirocco Jerry

Hmm..
I guess a negative attitude could misunderstand a bit of that,

..I was simply saying try to take care of your equipment, and it will serve you well.
train your employees to help the equipment last, and it can.

I can share a wealth of information that can help you troubleshoot problems that are extremely common in pressure washers.


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## RH

Sirocco Jerry said:


> Hmm..
> I guess a negative attitude could misunderstand a bit of that,
> 
> ..I was simply saying try to take care of your equipment, and it will serve you well.
> train your employees to help the equipment last, and it can.
> 
> I can share a wealth of information that can help you troubleshoot problems that are extremely common in pressure washers.


Clearly you've been on the receiving end of these type of complaints and must be sick of it but can you not see who has the negative attitude in this thread?


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## bobmax8

*pump broke after half hour*

I bought a chore master 3000psi today so I could have two pressure washers on the job, my other one is a four year old pacific hydrostar 2600psi. In a rush I added oil and started it up, after about a half hour it lost constant pressure, I think I over filled the oil so I drained some out and checked to make sure that the oil level was correct. But it still didnt keep pressure so I returned it. Do you think I caused the problem? or might it have just been a defective pump.


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## SouthFloridaPainter

I have a 3500 psi belt driven PW.

The pump had an oil leak for a while, I would fill before every use. Only once did it get too low on me and it started smoking a bit. Used machine twice afterwards and worked.

A friend borrows and I believe he used it with no oil.

Machine starts fine, but zero pressure now. Belt is fine and everything is turning.

What do you think?


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## Sirocco Jerry

*Pump overheated from the wrong oil..*



bobmax8 said:


> I bought a chore master 3000psi today so I could have two pressure washers on the job, my other one is a four year old pacific hydrostar 2600psi. In a rush I added oil and started it up, after about a half hour it lost constant pressure, I think I over filled the oil so I drained some out and checked to make sure that the oil level was correct. But it still didnt keep pressure so I returned it. Do you think I caused the problem? or might it have just been a defective pump.


The overfill might have blown a seal on a hotter day,
but, if the back-end overheated from the wrong oil..
Cheap water seals will blow under pressure faster than cheep oil-seals will blow under low-pressure... so without actually having an oil leak, the back-end could allow the front-end to overheat faster than usual, while the gun was off, between spraying.
Those "all-in-one" pumps are SO easy to overheat in bypass, you probably just didn't realize you layed the wand down a minute too long.


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## Sirocco Jerry

*Pump "smokes"*



SouthFloridaPainter said:


> I have a 3500 psi belt driven PW.
> 
> The pump had an oil leak for a while, I would fill before every use.
> Only once did it get too low on me and it started smoking a bit.
> Used machine twice afterwards and worked.
> 
> A friend borrows and I believe he used it with no oil.
> Machine starts fine, but zero pressure now.
> Belt is fine and everything is turning.
> 
> What do you think?


call me on this one, we need more symptoms before we can do the troubleshooting..
does the pump leak oil, or water ??
Maybe the pump-shaft turns, but the rods are all shattered.
We saw one of those in our service dept. just last week.
..If your pump has aluminum-alloy riods, instead of forged-bronze rods,
..they are surely laying in pieces. ..small and medium size pieces.


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## SouthFloridaPainter

I gave to a friend of friend about 4 days ago to see if he could diagnose the problem, I'm not sure he's qualified to do so though. I should get it back soon. Had a guy tell me yesterday, I can pick up a remanufactured one from a local repair shop here for around $250 - $300. I was told the new price was around $800.00.

The pump is MI-T-M. Now that I think about it, when it was returned, (over-filled with pump oil), there may have been aluminum shavings in it. Is that possible? Its not a cheap pump, should have the bronze I guess? The pump was leaking both oil and water by the way.

Anyways, thanks for taking the time on this.


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## Sirocco Jerry

slide a new pump on that motor, BUT..
this time, get one plumbed properly.

e-mail me for more details


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## SouthFloridaPainter

Sirocco Jerry,

I opened up the pump today ( AR4037 ) 1750 RPM Belt Driven

The ceramic plungers look solid, two have a very fine line crack, feels smooth under finger, but you can see a line on it. It looks more like a line drawn with pen. I'm assuming its a crack and not some kind of marking.

If those plungers are fine, could it have been something with the unloader?

My problem was zero pressure. Any ideas. 

I know all seals, oil rings, etc should be replaced, but none of those things would cause zero pressure, right?

Thanks


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## Sirocco Jerry

*Pump evaluation*

....


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## Sirocco Jerry

*Pump evaluation*

cracks in the ceramics are a dead-give-away the system has overheated in bypass,
then the gun was opened again, allowing cold water to rush-into the pump.
This reminds me of my older brother at 6 years old, boiling marbles and dropping them in ice-water..
(I guess this was my first science experiment.)
Aaaaanyway..
you MUST replace those ceramics with new, and plumb the pump so that can't happen... add a high-volume bypass.

Now, imagine the plungers are "that" hot, as the bypassing water is getting hotter, and hotter..
Can you see the seals surviving that trauma??
of course not.. replace them, AND the unloader.. It's not worth rebuilding.

And.. the oil in the crankcase is full, clean and perfect, right ??
so.. whilst you have the head off, inspect the crankcase seals behind the pistons..
..make sure they weren't overheated too.. they should not be seeping oil.

Also, before you order up those HP seals, and a new unloader valve,
look at the pump's 6 check valves.. they COULD BE HEAT-DAMAGED TOO.


I love the abuseability of AR pumps :{)


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## SouthFloridaPainter

Thanks for taking the time to respond, I'll be changing out the pump.


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## wills fresh coat

i would never buy a pw uless it is equiped with a "cat" pump,you pay a little more but it will be worth it in the end


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## Sirocco Jerry

It is difficult to get "Long-Term-Low-Cost"
out of a Cat pump for the same reasons as other "throw-away" pumps..

Cat uses aluminum alloy rods.. they fail easier when the oil is low or contaminated.
Cat has noticeably higher prices on parts that AR, Comet, General, Giant, and others.
Some of Cat's designs are more difficult to troubleshoot than others.
Some of their designs are more difficult to rebuild than others.
Plumbing them correctly can make them last a long time,
but repair bills are USUALLY better spent UPgrading to another pump,
with beefier rods, less expensive parts,
easier to rebuild, easier to troubleshoot,
easier to Long-Term-Low-Cost.

60% of our "dead-pump" room.. is the 2 shades of Cat blue.

One more thing.. you can buy "Cat-Oil" for 50% more than regular hydraulic oil.
Difference I believe, is just the added red color.

I'm simply trying to help.


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## wills fresh coat

thanks for the reply, i guess i've just had good luck with the one i've owened


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## Sirocco Jerry

Luck comes to those with a BMP program..
I'm sure you took care of it.. every time you used it.

Whatever pump you "like"..
Make sure it is plumbed for reliability, and there you have it.

Take care of it with reasonable Best Maintenance Practices..
and good luck will be yours too.
:{)


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