Kubota L245DT Loud Knock?

[metalic53]

I have an older 70's model 4x4 tractor. I was mowing the pasture the other day and the motor started knocking real bad, im new to diesels so i thought it was a rod bearing going out. Now i'm thinking it may be an injector.
I took all injectors out and left them connected to the high pressure pump to make sure they were all spraying and they are. The spray pattern looks good for each injector i think. I put them back in the tractor and the knock is still there. drained diesel and put new fuel filter in with new diesel and bled the lines, same knock. I then started cracking the high pressure line nuts to see if a certain injector was the problem. The first injector nut i loosened the knock got softer but still there. The second injector was about the same. When i loosened the last injector the tractor immediately dies.... Before i go buy 3 new injectors does anyone else have any suggestions?
Thanks

 

[North Idaho Wolfman]

Pull the injectors out and have them tested.
I would also do a compression test, if you have any knock on the compression test, your looking at a rebuild!

 

[btbaxter]

I had a similar problem and really thought it was a rod based on experience with gas engines. It turned out to simply be air in the system. My L3600 has a nut type of bleeder valve and when I loosened that with the tractor running I heard some air come out and the knocking went away. I think the air got in there because I ran the tank low and had in on some grades that probably caused the fuel to slosh around and introduce air. Hope that helps

 

[08k8]

I had a similar problem and really thought it was a rod based on experience with gas engines. It turned out to simply be air in the system. My L3600 has a nut type of bleeder valve and when I loosened that with the tractor running I heard some air come out and the knocking went away. I think the air got in there because I ran the tank low and had in on some grades that probably caused the fuel to slosh around and introduce air. Hope that helps

Today, I was working on a steep slope pulling some firewood out. I made about 4 pulls today and 3 yesterday. It's 19 deg F here and the tractor was running fine. I chained up a log and all of the sudden, it started knocking. The oil light was NOT on... Could this somehow be air?? Metalic53, did this work for you?

 

[North Idaho Wolfman]

Today, I was working on a steep slope pulling some firewood out. I made about 4 pulls today and 3 yesterday. It's 19 deg F here and the tractor was running fine. I chained up a log and all of the sudden, it started knocking. The oil light was NOT on... Could this somehow be air?? Metalic53, did this work for you?

When leveled out did the knock go away?

 

[08k8]

NO- I drove the tractor back to the shed and it knocked the whole way. I must say though that it was a short trip up-hill and straight to the shed.

It ran about 1 full minute knocking and my hope was to get it shut off ASAP to avoid / minimize any damage.

Thoughts?