Injection pump

brooster

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B5200, BX2360, L3940, Z781i KW
May 15, 2021
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I have received a replacement injection pump for my Kubota L3940, my question is if changing one pump for another is the only adjustment the shims? I am going to also order injectors and replace them at the same time, it appears that I am still getting fuel in the crankcase, I have been hesitant to run it for fear of damaging the engine, it only has 700 hrs on it.
 

rentthis

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I can't think of a route for fuel to get from the injector pump to the crankcase. Are you sure your fuel pump isn't the culprit?
 

brooster

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I have been told that fuel can get past the seals in it, I have replaced the lift pump, the first replacement pump was leaking from the bowl so replaced with a second one, but what little I have run the tractor the oil level still seems to be rising
 

Edke6bnl

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My old Ford tractor would fill the oil pan with diesel. I made a point of closing the valve from the fuel tank and it stopped. No sure how it got pass the injector pump and injector. Unless it leaked through the injector housing to oil pan
 

brooster

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B5200, BX2360, L3940, Z781i KW
May 15, 2021
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My old Ford tractor would fill the oil pan with diesel. I made a point of closing the valve from the fuel tank and it stopped. No sure how it got pass the injector pump and injector. Unless it leaked through the injector housing to oil pan
My tractor has been sitting for about two weeks now and oil level has remained the same, so this is happening while running
 

#40Fan

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Jul 21, 2022
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Not uncommon for a common rail high pressure pump to leak into the gear case through the front seal.
 
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brooster

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B5200, BX2360, L3940, Z781i KW
May 15, 2021
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Not uncommon for a common rail high pressure pump to leak into the gear case through the front seal.
So back to my original question about the pump, is there any other adjustments on the pump other than the shims between the pump and the block?
 

North Idaho Wolfman

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So back to my original question about the pump, is there any other adjustments on the pump other than the shims between the pump and the block?
No other adjustment necessary, just put back all the old shims and your good to go!

Oil in these will always smell like diesel, and it's more common for the hydraulic pump to leak at the seal and put hydraulic fluid into the crankcase than it is for diesel to get by the Injection pump.

Mark the dipstick on the hydraulics then run it a while and recheck, it will only drop a little to rise the engine level a lot.
 

North Idaho Wolfman

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Leaky injector very possible
No it's not, a leaky injector would not put fuel in the oil while running, at least not with it running properly, and it would be smoking like mad!

And injectors only have pressure and flow when the engine is running, not when it's shut down.
 

brooster

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May 15, 2021
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No it's not, a leaky injector would not put fuel in the oil while running, at least not with it running properly, and it would be smoking like mad!

And injectors only have pressure and flow when the engine is running, not when it's shut down.
Wolf man, I thank you, you have been most helpful, I will check the hydraulic fluid, where is the hydraulic pump on this tractor?
 

North Idaho Wolfman

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Wolf man, I thank you, you have been most helpful, I will check the hydraulic fluid, where is the hydraulic pump on this tractor?
The hydraulic pump is directly behind the injection pump.
 

brooster

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Is there anyway to determine whether it’s diesel or hydraulic that’s leeching into my oil? I did take and save a sample of the oil when I changed it after my runaway.
 

brooster

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Is there anyway to determine whether it’s diesel or hydraulic that’s leeching into my oil? I did take and save a sample of the oil when I changed it after my runaway.
Also and I don’t know if this will help, all I run in my tractor is off road fuel so it has the red dye in it, would this show up in the oil?
 

North Idaho Wolfman

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Also and I don’t know if this will help, all I run in my tractor is off road fuel so it has the red dye in it, would this show up in the oil?
You would have to have a sample tested, even then it's hard to determine if it's a normal residual level of diesel, oil and diesel mix really well.
Nope the off road dye won't help you.

Really the only way to determine what it's doing is to monitor levels.

How much is the dip stick gaining, in lets say 8hours of run time?
 

brooster

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You would have to have a sample tested, even then it's hard to determine if it's a normal residual level of diesel, oil and diesel mix really well.
Nope the off road dye won't help you.

Really the only way to determine what it's doing is to monitor levels.

How much is the dip stick gaining, in lets say 8hours of run time?
I have been hesitant to run it much, I check the oil and twice have drained enough to keep it from being over-full, the last time I got it about 1/4” below the full mark. I’ll try and run it some tomorrow and check levels and time and let you know. Thx again!
 

ferguson

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I have received a replacement injection pump for my Kubota L3940, my question is if changing one pump for another is the only adjustment the shims? I am going to also order injectors and replace them at the same time, it appears that I am still getting fuel in the crankcase, I have been hesitant to run it for fear of damaging the engine, it only has 700 hrs on it.
Fuel pump also & understand this quiet common
 

Russell King

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Is there anyway to determine whether it’s diesel or hydraulic that’s leeching into my oil? I did take and save a sample of the oil when I changed it after my runaway.
Replace the seal in the hydraulic pump and see if the engine oil level stops rising is probably the easiest way to know.
 
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