General Pump lost pressure, rebuild or buy new?

Gentlemen, I purchased a since-discontinued Dewalt 3750 PSI 4GPM cold water pressure washer, it came with a Honda GX 390, which works great, and a General Pump TX1510A pump, which seems to have stopped working.

I’ve used her for about 100 hours so far this season, and she has worked great, I got to a job yesterday and the machine turned on, but the pressure was only about 75% of what it normally was, and the engine was running fine. After about an hour, the pressure just kicked back on to 100%. After running out of gas, I started her back up and have now lost pressure completely.

At first, I thought the problem was just the unloader, I removed it, there is no damage, I put it back on. The next step was to remove the pump itself. I have some pictures here.

I’m debating ordering parts to rebuild this (I believe an outdated model) General Pump or upgrading to either a CAT, or I know everyone here is more of a fan of UDOR pumps.

I bought the machine for $500, so spending $500 more on just a pump doesn’t sound too appealing right now.

As you can see here, the ceramic plunger in the center is damaged, though I don’t know that this damage could have caused the total loss of pressure?

I’m not sure if I should stop here and buy another pump, or continue taking it apart, looking for damage, and trying to rebuild it.

Upgrade to 5.5gpm gear drive.

Can find cheaper elsewhere.

So, here is the deal. You don’t need to take the unloader off to check it. Look at the spring when you squeeze the trigger and see if it is moving. If it isn’t. check the shutter valve, then replace. On the pump, easiest to check the check valves first if loss of pressure. If they are good, then you check the pistons. In all honesty, if it is a general pump and you got over a hundred hours on it, trash it. You can rebuild it but you will be doing the same thing in under a 4 or 5 hundred hours. If you don’t so a lot of washing and 4 or 5 hundred hours is a long time, maybe take the gamble. Want a pump that will go 4 or 5 thousand hours, go udor. General sells off of name recognition and because vendors know they have a constant revenue stream off selling rebuild kits and replacements on disposable pumps.

You can get them for $750 if you shop around, but then at the end of the day all you have is a general pump

Buy this and go make money.

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Really appreciate the quick replies guys, I ended up finishing the job I got started on with my old 2800 psi machine, and it was BRUTAL! I’m headed to the store tomorrow for the right socket to take off and check the valves, I’m going to price out rebuilding the pump while I have it, but am also going to shop around for a Udor pump.

I’m kindof a newbie, obviously… a 5.5 GPM pump that’s only putting out 3500 PSI is still more effective and powerful than a brand new GP that does 4.0 GPM at 4000 PSI? I totally get that Udor is way better quality, just worried about paying twice the price.

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You will only get about 2200-2500 psi with the 5.5gpm pump on that motor. That is plenty for residential.

I would not spend $400 on a 4gpm direct drive GP. You wont find a better price on that udor I linked to

Really appreciate it Joe, I keep going back and forth on all of this and looking at all the different models of pumps I could invest in. It seems like CATs are about the same price as Udor, so i’d rather go with Udor.

The link that you sent will definitely fit my Honda gx390, right? And will that pump actually give me more power than the GP I was running? It’s a Dewalt machine that claims 3750psi and 4 GPM. I’m 100% in agreement that I’d rather have a pump that lasts 4000 hours rather than 400. To that end, i’m not even sure its worth ordering the kits to rebuild the GP.

Lastly, its obviously everyone’s busy season! I need to order something this moring, I already resechduled the rest of this week’s jobs :frowning:

I soon as I hit send, I figured what the heck, I’m ordering the Udor :slight_smile:


I’m learning rather quickly, and at times the hard way. Don’t be penny pinching on the very equipment that is putting in work and cashing check. I’m wishing that I would have spent the extra $1500 and got 8gpm instead of my 5gpm. It’s definitely getting the job done but a faster rinse would be ideal. Lessons learned. Find somewhere else to save money


It should bolt up directly to your motor. You will gain gpm but lose psi. You don’t need 3000 psi for residential work

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Sorry to add to an old thread. I also have an old Dewalt GX390 (at least 12 years old) and the ceramic pistons have cracked. Rather than rebuild I would rather purchase a new pump. While I would like to purchase the above udor pump I use my washer maybe once a year for my house so I will never reach 500 hours of use. I would really appreciate advise on a more affordable easily swapped out pump (something that could be shipped fairly quickly would be nice).
Thank you

I was looking at this:


Any advise will be greatly appreciated.
BTW what do I do with my old pump…seems such a waste to throw it away.

You could certainly get that pump, I’m sure it would work fine for your purposes. The other guys might steer you to an actual pressure washing vendor however.

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If it’s just once a year use, sell the gx390 for a couple bucks, and just rent a pressure washer from Home Depot when you need it, or better yet, just hire a pro and sit back and relax.

It might be over kill but this is what I replace your old pump with. I did something similar about 8 years ago. I bought a Craftsman 2.8 gpm PWer with a bad pump for a song and added a solid Cat pump. Loved it. Good luck.,ss:67&prmd=snmiv&prds=epd:16001762938451758543,paur:ClkAsKraX1bvfhSzHF6lUFTJ_8eZqdg3rBalM9Vc3iYfR4jsN-zq2rsifmzzFP_uf-vMeSwrQwlcmXS9pk-qOm7x06s-spx8tQgFn0dmewYCQWzZhhPzNErHWRIZAFPVH72InmNwuZ98MUYuX42mdE1Lzkmjzg,cdl:1,prmr:1,cs:1

Thank you everyone for your quick responses!
BigJake your idea is not without merit!! It certainly would be one less tool to have to winterize and would free up some space in the garage. I will have to look into how much a pro would charge. Thanks for the link Sasquatch but link is to a general pump not a Cat pump.

Hi FATJOE! 2 years ago I took your advise and upgraded to the UDOR pump you linked here. A 5GPM MKC 18/24. It’s worked like a dream for 2 years. For the past few weeks oil began to “bubble” out of the oil dipstick on the top of the pump, I assumed the plastic dipstick/cap was broken. The machine had been working fine, until yesterday when it finally lost pressure. I changed the oil again, and the cap, but that didn’t work. Do I need to get a new seal kit? We’re the bubbles a result of water getting into the pump through a busted seal? Happy Memorial Day!! You’re the man btw, this pump has treated me very well!