Hello All. This is my first post here but I have been checking these forums out for a bit. So far I have found the forums to be very helpful and have come across some smart cookies on here. I tried searching around for the problem I'm having w/mixed results, so I felt like I can possible get some better information from people if I post about my specific issue. The backhoe is a 1989 JD 310c with 3540hrs on it. I just purchased it from an older guy that used it around his property for doing firewood and other small things. The machine as a whole is in very good shape, no rust, everything works with the exception of the overhead work lights, and it seems to be well maintained. The previous owner stated that he had previously had a weird issue where the machine was "running rough/not right" and therefore he replaced the lift pump, injection pump, and all the injectors to fix the issue. At the time, it fixed his issue. Fast forward... I went to look at it recently. The engine ran great when I looked at it, so I bought it. Now: It has been a couple of weeks since I bought the machine and it has been sitting in my driveway, with out being used. I had some time today to go check it out and do some maintenance. Before I started the engine, I decided to check the oil. To my surprise, a geyser of diesel fuel came out of the dipstick and continued to drain. I wound up draining about 8-10 gallons of fuel mixed with oil out of the drain plug. I proceeded to try to investigate where the fuel could be coming from. What I checked so far: I pulled the brand new lift pump off while keeping it piped from the tank and proceeded to pump it to see if it was leaking past the seal into the engine, but it isn't leaking. From what I've found out, the injection pumps can leak out of the front into the engine, or it can be an injector that won't seat shut. So, before I deal with timing the motor/injection pump, I was advised to pull the oil pan and see if I can locate where on the inside of the engine the fuel is coming from; ie. down a cylinder -> injector, or, in the front of the motor -> injection pump. I'm posting this here to hopefully get some insight to my plan and get some educated discussion of the situation. Thanks for all the help!! I appreciate it.
Check the diagram in the lift pump may be a start. I can't think of any other way that much diesel could get in the oil with it just sitting. Some good mechanics here I'm sure they can give much better advice then me.
If that's the injector pump I think it is you have a failed umbrella seal on the pump shaft.
I wouldn't bother taking the oil pan off, if you have the transfer pump loose on the engine, pull it out enough that the arm is clear and not dripping into the engine, the pour some of that fuel oil mix back into the fuel tank, if it doesn't leak there, but does drain back into the oil pan, then it's the injector pump. The transfer pump won't leak if there's no fuel in it though. If it ran smooth then the injectors are fine.
That pump is easy to check.. Remove the return line and ALL THE FITTINGS off the top of the pump.. Now pull the small plate IN FRONT of the pump.. Next apply about 3-5 psi into the hole in the top cover and look/hear for the fuel leaking.. Good luck
The thing about THAT PUMPis, when he replaced the pump, the drive shaft stays in the engine.. U change the seal on the old shaft and slide the pump up on it.. It’s VERY EASY to roll the first seal, & I’ll bet that’s what happened, taking into account how much fuel u drained out.. U can limit the amount before you get it fixed by shutting off the fuel at the tank..or pinching a rubber line closest to the pump inlet.
I have gotten a lot of responses. Thank you all very much for the information provided. It is appreciated. I will begin by troubleshooting the injection pump as thepumpguysc stated. I will post back with my findings and results. Thank you all very much again.
Welcome to HEF, Clunkahollic !
PumpGuy thank you for the solid insight, before I start turning any wrenches, I just want to confirm what it is I am to do and what the problem could be. I sourced the Pump manual online and was able to get some exploded views. I just want to confirm these are the seals in question. And also, for the top of the pump, I see the return line right on top and only a set screw with a jamb nut on it. Are these the only 2 things to remove before applying 3-5psi to the return hole? And the front cover I believe you are talking about is the one I photographed. Thanks again for all the help, I need to get this machine up and running.
View attachment 256756 Unless you are talking about the electrical connections/studs as well? Sorry for the misunderstanding on my end.
No, #27 is the return fitting, the one with the bare steel line that returns fuel to the tank. If TPG said the return HOLE, then he meant to remove that fitting because it's a check valve, sometimes. Do not remove the circled bolt and lock nut unless TPG said so.
Ok, yes this makes much more sense, again it is my misunderstanding. I will go check this and post my results. Thank you all again.
Thank you for all the help here! I finally had time to remove the injection pump Sunday and confirm that the first driveshaft seal was indeed folded over. I replaced the seal and used the seal tool to install the pump. My only concern at this point is, how do I monitor any fuel leakage from here on out? Before the oil pan was drained and I would leave the drain plug in and just remove the plug after some time and see if any diesel accumulated. Now that the oil is in the engine, what is suggested to monitor leakage? I know the fuel should pool on top of the oil if the engine isn't started, so maybe let it sit for a couple days then I'll check on the dipstick and see if it shows anything. Other ideas are welcomed. Thanks again for the help.
Just watch the level on the dipstick.
Hello Clunkaholic, I will be re-installing the injection pump on my 310C soon and would be interested buying/renting/borrowing your seal clamp tool to not fold the umbrella seal over. My 310C is also an '89 and has 3590 hours on it. I've owned it for 20 years and it is just a farm machine so gets sporadic use. I've had to fix other things on it before so it has been a fun learning experience. The only thing that doesn't work on mine is also the lights, so it looks like you bought the twin of my machine! While I wait for injection pump to come back, I'll work on the lights...
I'm sure Pumpguy will provide you with detailed instructions so you have painless installation, don't know how much room you've got in between block and pump to work but I have used a piece of rolled up beer can (several available in my shop) to compress and protect the seals on at least 5 pump installs with great success. Of course you can buy one, was just using what I had available.
I’ve heard of people using beer cans, a/c line tools, small Allen wrench, piece of a zipper plastic bag to slide the seals on the shaft.. and I think my all time favorite is a: feeler gauge to ease the first seal into the pilot tube, w/o rolling it.. ALL THIS in lieu of not having the proper tools.
Newbie007.. if u still need the tools, lemme know..