L5030 injector pump leak

THATS BECAUSE your not supposed to be working on it..
BUT if u must..
The Delivery Valve Holder Oring # is>090139-0410
The Delivery Valve Gasket # is>090137-0130

Those P# are Denso part #'s.. the inj. pump manuf..
I suggest u do ALL of them.. 1 @ a time.. The Holders get Torqued to 30-35 FT lbs..
DO NOT even attempt without a torque wrench.!!! Good Luck.

What makes you think it is leaking diesel? Is it leaking externally or do you have milky oil?

If its milky oil I would confirm if the tractor does not have a cracked head, they usually crack on the #4 piston to coolant passage.

cwitherington said:

It is leaking externally. No milky oil thankfully. I know it’s diesel because it’s red. I’m using off-road. What typically causes the head to crack? Is it an hours thing, overheating or just general abuse?

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From overheating. Where is it leaking externally?

Can you take a photo?

If it is leaking at one of the 4 injector outlets, it would be pulsed. So when idling you would see it squirt and that cylinder would not run correctly.

Odds are you leaking from the banjo fuel inlet which has two copper gaskets that need to be replaced and torqued correctly.

TOM, go back & READ the 1st post..
He said he had a PUMP leak.. & u went straight to a cracked HEAD.. geesh..

Now come on, this isn't that other forum where guys love argue and put each other down.

Tom owns the same model tractor and was offering some ideas to check. Often times a poster says something that can be clarified with a few questions.

Just get as much stuff out of the way of the inj. pump & change the orings & gaskets.
Start at either end of the pump & remove all the injector lines & get them out of your way.. what I'm saying is> don't start at the middle & try to do that 1 first.. get all the lines out of the way..
Good luck.

cwitherington said:

Just a few more pictures

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Let's just ignore the pump guys suggestions for 5 minutes, because all he sees is a failed o-ring and it was really nice of him to find you the part numbers for those, but I have seen many low hour and high hour kubota's and I have never seen those fail. All they ever see is mechanical pump pressure (5-9psi) and they have a brass washer (second part number he quoted) that is torqued down to 30ish ft-lbs (and can't loosen as there is a holder in place) and a o-ring (first part number he quoted). Those are two points of failure that are highly unlikely to fail before anything else.

Here is what I can see.

Your injector "jet start cock assy" like kubota calls it PN "1431160504" or the only thing in your picture that is not painted grey like the engine looks like it had been replaced. Most likely got broken off or damaged at some point in its life. My question is, what happened there and why is the line clamp not installed. Was the assembly installed with teflon tape/sealant? or was it just put in there dry? (it does not have a copper washer).

When it was put in place were the lines removed? were the copper washers on the fuel banjo replaced? was it tightened or torqued.

Any one of these could easily cause your issue. When the engine is running at higher rpm it could be shooting towards the area that you see as leaking.

Here is what I would do with minimum time and expense, and without having to disassemble that side of the engine to access the injection pump to replace the oring and brass washer that are unlikely your problem.


1. Remove both fuel lines and inspect them for cracks.
2. remove the jet start cock assy, inspect and seal with teflon tape or preferably pipe sealant.
3. remove the banjo bolt and replace the pair of copper washers. PN: 1540196650 Kubota.
4. Reinstall fuel lines carefully and make sure both fuel line clamps are on correctly and tightened.


Maybe 30mins of work and $5.00 for the copper washers.... if it does not solve your problem you at least know it won't be a problem for quite some time.

cwitherington said:

Thank you both for the suggestions.

To answer some of your questions Tom, I am not sure what happened to the jet start cock assy. I bought this tractor about 40 hrs ago, it now has around 790hrs. The jet start cock was like that when I got it. I assume the line clamp you are talking about is on the over flow line from the injectors. If so, I was installing a new line when I took the picture. I have the rest of the fuel lines on hand, just have not installed them yet.

I will order the copper washers for the banjo bolt and replace them.

As for the sealant or teflon tape (I have both), where exactly are you saying it should be? on the threads of the jet start cock assy?

I assume the torque specs for these are in the WSM but if not, I would be interested in those as well.


Thanks again for the assitance.
CW

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The sealant should be between the jetcock assembly and the banjo bolt leading into the injection pump.

Not to hijack this thread, but I logged on to ask about the same leak I have on my L2550. Mine leaks (weeps) out of where the "holder delivery valve" (description from the parts manual I have) screws into the top plate. I was going to order the "o-ring" and the "gasket delivery valve".

And like the OP, mine weeps fuel and it runs down the block to the ground, red drops......

Do these two parts, o-ring and gasket sound like the proper items to fix the leak?

Great, I’ll stop by the dealer tomorrow and get them ordered.

U might be a few dollars ahead getting them online.??

CWitherington and Stob, both these areas (jet start cock and delivery valve holder) are what I went through to stop the leak on my pump. Initially I was convinced it was the jet start cock, and replaced that. Didn't work, got the whole area really clean and dried it off with air, started engine, and at idle over several minutes of really close inspection (with a torch to highlight the glistening diesel) it became obvious that diesel was very slowly welling up from the point where two of the delivery valve holders screwed into the top of the pump. I fixed it with the O ring and washers referred to above. The guys on this forum offered really good assistance for doing it right first time. If you are interested in more detail about the "how to" search for the thread "dreaded delivery valve holder".

May the Orange Force be with you

Could be jet start cock was replaced for the same reason I replaced mine - and unnecessarily as it turned out.

thepumpguysc said:

U might be a few dollars ahead getting them online.??

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What source are you using for on line parts? The reason I ask, the dealer I use is in the county where I work, not where I live. And at the end of this month, I retire and it won't be as convenient to get to.