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330C hydraulic pump whining

Danfromcomo

Danfromcomo

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Sep 11, 2020
Messages
65
Location
Texas
Hey guys. I have a situation going on here and was looking for some insights. Did some searching and couldn't find an answer.
My 2002 330C SN DKY624 has 14k hours on it, I just got in a couple months ago from a 1 owner company in MO. The guy who sold it to me said that the pump would make a noise when it got warm and you were doing several functions at once. Sure enough it make a whining sound but then after operating temps get up to about 3/4 on the guage if working it hard it will start a jerking movement and making a creaking noise.
I did notice that there were some air bubbles in the sight glass.
Here's what I have done.
Shortly after I got it the "return hyd filter is plugged" message came on.
I replaced the return filter, pilot and case drain filters. No noticeable shavings in the return filter, I did not cut open the other 2.
The problem still occurred.
After reading up on it I cleaned the screen in the tank and the one near the pilot filter.
Neither had a lot of metal shavings, it wasn't much but more rubber and silicone type debris.
After cleaning both , I ran for 30 min and it did the same thing.
The "return filter is plugged " message has came on again.
I feel like the pump may be starting to fail but really figure I would have more metal in the filters.
Any ideas on what to do next?
Should I rebuild/replace the pump before it craters and trashes the entire system?
Thanks in advance, you guys are always great.

Danny
 
Universal Parts

Universal Parts

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china
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I believe it's due to bearing wear or a loose impeller.
 
John C.

John C.

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It might be likely that the pump is original and if so it is on borrowed time anyway. It basically just unplugs from the flywheel housing like a transmission after you pull all the hoses and connections. It would be a good idea to replace the hydraulic oil although many people put a vacuum on the tank and then cap off the connections and not lose much if any oil at all. I don't know if you Cat dealer rebuilds them, most do factory exchanges and they are big money. We have some rebuilders around here and that's a big risk. There is a flexible coupling between the pump and the flywheel that will most likely need to be replaced.
Good Luck
 
Universal Parts

Universal Parts

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china
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John C. said:
It might be likely that the pump is original and if so it is on borrowed time anyway. It basically just unplugs from the flywheel housing like a transmission after you pull all the hoses and connections. It would be a good idea to replace the hydraulic oil although many people put a vacuum on the tank and then cap off the connections and not lose much if any oil at all. I don't know if you Cat dealer rebuilds them, most do factory exchanges and they are big money. We have some rebuilders around here and that's a big risk. There is a flexible coupling between the pump and the flywheel that will most likely need to be replaced.
Good Luck
Click to expand...
The Caterpillar 330C flexible coupling uses a buffer rubber with aftermarket code 140H. This model is unique in that while other models use a single, integrated buffer rubber, 140H consists of four separate rubber components.
 
Danfromcomo

Danfromcomo

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Sep 11, 2020
Messages
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Location
Texas
Well, I checked on some rebuilt pumps and they are going to run around 20k. Since I only paid 35k for the machine and supposedly it has been making this noise for quite a while. Im going to keep working it till the pump quits.
The only other thing that I can think of is to replace the cap on the hyd tank. Since there was no pressure when I opened it, I guess it could be bad and that may affect the hydraulic operations.
 
Universal Parts

Universal Parts

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Location
china
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Small-scale engineering parts distributor
Danfromcomo said:
Well, I checked on some rebuilt pumps and they are going to run around 20k. Since I only paid 35k for the machine and supposedly it has been making this noise for quite a while. Im going to keep working it till the pump quits.
The only other thing that I can think of is to replace the cap on the hyd tank. Since there was no pressure when I opened it, I guess it could be bad and that may affect the hydraulic operations.
Click to expand...
Is your refurbished pump assembly part number 1539185? In the Chinese aftermarket, a brand new one would cost approximately USD 3529.
 
Tones

Tones

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Mar 15, 2009
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A word of caution. Running pumps to destruction make a big job bigger because the debris can go throughout the hydraulic system. The entire system then has to be cleaned.
 
C

couesaddict

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Jan 30, 2023
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107
Location
Arizona
I had the pump set on our 330c rebuilt at a shop in Phoenix last year for $9,000. They used cat parts and bench tested it after. Machine had similar hours and symptoms. Was down on flow and making noise. You’ll definitely want to change the hub and coupler while you’re there. More than likely at those hours it’s about ready to spin through.
 
Danfromcomo

Danfromcomo

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Messages
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Texas
couesaddict said:
I had the pump set on our 330c rebuilt at a shop in Phoenix last year for $9,000. They used cat parts and bench tested it after. Machine had similar hours and symptoms. Was down on flow and making noise. You’ll definitely want to change the hub and coupler while you’re there. More than likely at those hours it’s about ready to spin through.
Click to expand...
Thanks man, thats a whole lot easier to do than a 20k reman unit. I have a couple of good Hydraulic shops around that I will check with.
 
C

couesaddict

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Make sure to give them the part number off of your actual pump when you talk to them so they can check on parts availability for it. Sometimes there’s updated part numbers on sis that may or may not have the same internals. Also, when you go back together with it, fill the tank then loosen the big suction inlet where it bolts to the pump to burp the air out of the line. I also like to flip the toggle kill switch that should be at the base of the seat and crank it several times without allowing it to start to get the rest of the air out. Starting a piston pump dry is terrible for it.
 
E

earthscratcher

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iowa
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excavating contractor
did u replace hydraulic cap, should have pressure on it if not its sucking air, not good on pump won't last long, also tighten clamps on suction hose, can suck air there to
 
S

Shimmy1

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North Dakota
Danfromcomo said:
Well, I checked on some rebuilt pumps and they are going to run around 20k. Since I only paid 35k for the machine and supposedly it has been making this noise for quite a while. Im going to keep working it till the pump quits.
Click to expand...

If you do this, you may as well figure on selling the machine for scrap price, because it will be worth less than that if you run those pumps to destruction.
 
Danfromcomo

Danfromcomo

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Messages
65
Location
Texas
earthscratcher said:
did u replace hydraulic cap, should have pressure on it if not its sucking air, not good on pump won't last long, also tighten clamps on suction hose, can suck air there to
Click to expand...
I haven't yet but I just ordered one. This cap has no pressure so im sure its sucking air.
The previous owner said it's been making the sound for a while. Hopefully too much damage was not done.
Thank you for the information.
 
Danfromcomo

Danfromcomo

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Sep 11, 2020
Messages
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Location
Texas
Hopefully the cap is the problem and it won't get to that point. But if the cap doesn't fix it, I will look to have it rebuilt as i dont need another pile off scrap iron around the house.
Thanks
 
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