M7500Dt bleeding

[Old Tractors]

Hello just joined up after randomly stumbling upon the page.

So we purchased a Kubota M7500DT back in fall. Everyone that dealt with it said it was hard to bleed, we found out the hard way. We ran it out of fuel once and took several hours to get anything for fuel up top to the injectors...and it still wouldn't fire. Manual was no use, couldn't find all the bleeders mentioned.. Took dragging the tractor down the road to get it going.

Now a couple weeks ago it died pushing snow...frozen lines were suspected. We managed to push it in the shop. Switched the filters got it all thawed out, filters bled and found the bleeders we couldn't find before. Got fuel flowing good to the bleeders on the inj. pump, but still can't get a good flow up to the injectors.

After cranking on the thing (hand pump doesn't seem to push fuel up past injector pump) for hours with the lines both loose and tightened down....we can't seem to get the lines to flow enough say its bled completely.

Any help would be nice. I was thinking of adding an electric pump for bleeding but not sure how (or where) to go about that either.

 

[North Idaho Wolfman]

If you pull the line on the output of the lift pump do you get good flow and strong pulses of fuel?

If you loosen the injector lines at the injectors and don't get pulses of fuel then you have either a feed issue to the injection pump, a linkage issue that is leaving the pump in shutdown/fuel cut off, or you have internal issue with the injection pump.

 

[thepumpguysc]

IF it has an electric shut off solenoid.. take it off..
Meaning, if the engine shuts off w/ the key switch, you have an electric shut off..
& put the throttle wide open when trying to bleed..
IF u did both of these & u have fuel UP TO the inj. pump & nothing OUT.. its gotta be the inj. pump, right? {stuck rack}

 

[Old Tractors]

If you loosen the injector lines at the injectors and don't get pulses of fuel then you have either a feed issue to the injection pump, a linkage issue that is leaving the pump in shutdown/fuel cut off, or you have internal issue with the injection pump.

When bleeding we get really good pulses of fuel out of the filter bleeders and the bleeders on top of the injector pump. We loosened a couple lines right behind the inj. pump and got fuel to drip out. tightened those back down and still had very little up top.
I doubt its linkage (from what we see its all set to "run" mode) or the pump itself. When it runs it run great with no hesitation or other random noises to make one believe the injector pump is going out. Could the lift pump be one going out? in that it can produce pressure to bleed the rest but not enough to push past the injector pump.

If you still think its the inj. pump.... How would one go about testing it with out removing it from the machine? and if one does have to remove it how hard is it to retime when reinstalling?

 

[Old Tractors]

IF it has an electric shut off solenoid.. take it off..
Meaning, if the engine shuts off w/ the key switch, you have an electric shut off..
& put the throttle wide open when trying to bleed..
IF u did both of these & u have fuel UP TO the inj. pump & nothing OUT.. its gotta be the inj. pump, right? {stuck rack}

I should of said it in the original post. its a manual pull knob kill, and we did have throttle set to wide open and knob pushed in. That it is the injector pump internally has crossed our minds, but refuse to accept it for as well as the tractor run when it runs....its just a pain to bleed to get it running again.

 

[JerryMT]

When bleeding we get really good pulses of fuel out of the filter bleeders and the bleeders on top of the injector pump. We loosened a couple lines right behind the inj. pump and got fuel to drip out. tightened those back down and still had very little up top.
I doubt its linkage (from what we see its all set to "run" mode) or the pump itself. When it runs it run great with no hesitation or other random noises to make one believe the injector pump is going out. Could the lift pump be one going out? in that it can produce pressure to bleed the rest but not enough to push past the injector pump.

If you still think its the inj. pump.... How would one go about testing it with out removing it from the machine? and if one does have to remove it how hard is it to retime when reinstalling?

"...we get really good pulses of fuel out of the filter bleeders and the bleeders on top of the injector pump. We loosened a couple lines right behind the inj. pump and got fuel to drip out. "

When you say "... behind the injector pump..." do you mean between the IP and the injectors? If so something is sticking inside the pump (the rack or the metering valve) as thepumpguysc says.

 

[JohnDB]

When you say "very little up top" I'm assuming you've loosened all the lines where they attach to the injectors and checked whether fuel is coming out?

 

[Old Tractors]

When you say "very little up top" I'm assuming you've loosened all the lines where they attach to the injectors and checked whether fuel is coming out?

That's the up top I'm talking about yes....up top of the head by the injectors. even pulled the lines completely off the injectors a time or two and got nothing. If we did get something it was only really small bubbles. If we had the lines loose and cranked it with the starter steady till the battery died then we'd eventually get the head faintly gleaming (light reflecting off) from a very fine layer of diesel.... tighten everything down, no start to finish off bleeding(like manual says to).

 

[Old Tractors]

ok so my brother got tired of it being in the shop. We hooked a chain pulled it out and down the road. Fired right off. Now it will start and run just fine till it needs to be bled again (the thing that is really bothering us). I'd hate to have to drag it each time it runs out of fuel. So I still need to figure out why it doesn't want to bleed.

Sorry if I sound like an idiot, I probably am. this is our first Kubota and compared to our other diesels (JD 2440 and IH 3588) this Kubota is a pain.(even with the manual). Those its bleed the filters a few pumps, 10 mins and your good to go.

Ok so Pumpguy and Jerry yous said something about a rack or something else possibly sticking, few questions. Why would they only stick when it runs out of fuel, and not every time the tractor is stopped? How can one find out for sure its sticking? How would one unstick them besides pulling the pump and tearing it down?

I'd hate to have to pull the injector pump if I don't have to (the old it works as is why tear it down). Beside the tractor has a heavy loader frame on it making any work on the engine a challenge. Thanks for the help so far.

 

[JerryMT]

ok so my brother got tired of it being in the shop. We hooked a chain pulled it out and down the road. Fired right off. Now it will start and run just fine till it needs to be bled again (the thing that is really bothering us). I'd hate to have to drag it each time it runs out of fuel. So I still need to figure out why it doesn't want to bleed.

Sorry if I sound like an idiot, I probably am. this is our first Kubota and compared to our other diesels (JD 2440 and IH 3588) this Kubota is a pain.(even with the manual). Those its bleed the filters a few pumps, 10 mins and your good to go.

Ok so Pumpguy and Jerry yous said something about a rack or something else possibly sticking, few questions. Why would they only stick when it runs out of fuel, and not every time the tractor is stopped? How can one find out for sure its sticking? How would one unstick them besides pulling the pump and tearing it down?

I'd hate to have to pull the injector pump if I don't have to (the old it works as is why tear it down). Beside the tractor has a heavy loader frame on it making any work on the engine a challenge. Thanks for the help so far.

You are not an idiot and we are trying to help you. It's kinda' hard to do that from 2000 miles away.

"I'd hate to have to drag it each time it runs out of fuel."

I'm confused. Is it difficult to start with fuel in the tank or are you running it out of fuel and having difficulty bleeding it?

As I understand your problem is once you shutdown, you can't restart and you do not have fuel beyond the injection pump with the throttle control wide open. I assume that your throttle linkage is moving the fuel lever from the stop cock position to the run position (you have fuel at the pump) and the fact that you can get it to run by pull starting could mean that that when pulling, the injector pump speed is faster and it becomes unstuck. I'll defer to the pumpguysc on that possibility.

Then you say:
"I'd hate to have to pull the injector pump if I don't have to (the old it works as is why tear it down). "

If you can't start the tractor with fuel in the tank and you have fuel to the injection pump, my conclusion is that your pump is not working. You have to accept that unless you want to continue pull starting it.

 

[Old Tractors]

You are not an idiot and we are trying to help you. It's kinda' hard to do that from 2000 miles away.

"I'd hate to have to drag it each time it runs out of fuel."

I'm confused. Is it difficult to start with fuel in the tank or are you running it out of fuel and having difficulty bleeding it?

As I understand your problem is once you shutdown, you can't restart and you do not have fuel beyond the injection pump with the throttle control wide open. I assume that your throttle linkage is moving the fuel lever from the stop cock position to the run position (you have fuel at the pump) and the fact that you can get it to run by pull starting could mean that that when pulling, the injector pump speed is faster and it becomes unstuck. I'll defer to the pumpguysc on that possibility.

I understand the difficulties of trying to solve problems with out being there. And I'm having a hard time explaining whats happening here (why I said I'm sounding like an idiot).

Yes, the trouble is bleeding and getting it to start after running out of fuel (or freezing lines, or changing filters), where system needs the air bled off. Yes (to ward off smart remarks) we check and add fuel as needed before trying to bleed.

If the machine is shut down with the knob or snubbed under load...it will fire right off no issue.

Speaking of the injector pump spinning faster pull starting it. The starter might be dragging down some too (unnoticed under normal starting conditions), giving us the trouble. Meaning that it don't get the engine up to the needed speed (to bleed and start), where as dragging the tractor down the road does.

Am I making some sense or still talking jibberish.

 

[Fordtech86]

I understand the difficulties of trying to solve problems with out being there. And I'm having a hard time explaining whats happening here (why I said I'm sounding like an idiot).

Yes, the trouble is bleeding and getting it to start after running out of fuel (or freezing lines, or changing filters), where system needs the air bled off.

If the machine is shut down with the knob or snubbed under load...it will fire right off no issue.

Speaking of the injector pump spinning faster pull starting it. The starter might be dragging down some too (unnoticed under normal starting conditions), giving us the trouble. Meaning that it don't get the engine up to the needed speed (to bleed and start), where as dragging the tractor down the road does.

Am I making some sense or still talking jibberish.

Hate to sound like an a hole, but if it only happens when you run it out of fuel, well then stop running it out of fuel!

 

[Old Tractors]

Hate to sound like an a hole, but if it only happens when you run it out of fuel, well then stop running it out of fuel!

Easier said then done...sometimes the fuel runs out before you notice.....yeah just do this quick (it'll last that long) then fuel up, or runs out on way to fuel up....duh....

Then since it also needs to be bled (and give us trouble) when the lines before the injector freeze unexpected (like this last time) or routine maintenance (filter change).

All the more time wasted and swearing at the thing

 

[D2Cat]

I have to agree with Fordtech86, don't let it run out!!

It has a 19 gallon fuel tank. If the fuel gauge does not work, or it doesn't have one, use a dip stick...but when it gets down a 1/4 tank dump in 5 gallons of fuel.

You'll never run out, and you'll always have fresh fuel.

 

[sheepfarmer]

Yeah but don't discourage him from changing fuel filter.

 

[JohnDB]

Old Tractors - did you get the problem solved -are you able to bleed the system and get the tractor started without dragging it down the road? If so what was the issue or what did you do to fix it?

 

[Old Tractors]

Old Tractors - did you get the problem solved -are you able to bleed the system and get the tractor started without dragging it down the road? If so what was the issue or what did you do to fix it?

Now that we dragged it down the road it starts with starter no problem. Haven't needed to bleed it again.... yet.

However we still didn't figure out why it don't bleed yet (when run out of fuel) either. As you can read above didn't get any more leads as to what to look into or ways to test things for issues.

I could possibly pull the injector pump and send it out to get tested ect....but the way the tractor runs (when it doesn't need to be bled), I don't want to if it can be avoided.