M8560 High Pressure Supply Pump Replacement or Rebuild? $$$

[markjm]

Hi all,
I have a 2014 Kubota M8560-HDC12. I love this tractor but recently it wouldn't start. Tracked it down to a fuel issue and eventually pulled the High Pressure (Injection) Supply Pump. It appears debris got into the pump via dirty/bad fuel. The parts appear damaged but the diesel injection outfit didn't pull it apart and give any more details than that to my mechanic. So we don't know what parts are damage.

They also said that Kubota won't sell parts?

This pump part number: 1J500-50504 and they are around $2400 new!

I have been told that no-one rebuilds these and everyone just wants to sell me a new pump which is about worth its weight in gold Before I mortgage one or more of my children I was hoping someone on this forum has a direct line to the diesel gods and can give me hope?

So the options are:
1) replace the pump.
2) find someone who DOES rebuild these pumps.
3) find an alternate pump (Denso?). This is unlikely.

Any and all help and input would be appreciated.

Mark

 

[diesel85]

It's a Denso and it crosses with: 9729400-172

Do more research.

 

[markjm]

Thank you Diesel85, I figured it was a Denso and I appreciate the confirmation and part number!

 

[markjm]

Also, do you know if the injectors are also available under the Denso or another brand? At $1000 a pop these things are pricey!

 

[diesel85]

KPN: 1J500-53050 crosses with Denso Part #: 095000-9690

Good luck.........

 

[number two]

Try contacting thepumpguysc on this forum.
He's a rebuilder.
Good Luck!

 

[MHarryE]

As you probably know, a heavy duty hydrostatic pump is good for about 6500 psi and a Denso common rail pump can hit relief at 30,000 psi. So we’re talking super close clearances and tight tolerances. That’s why filtration has become more important. Our old 1939 TD6 International injection pressure was 1650 psi, my old L5740 max injection pressure was 2130 psi, and the relief valve on the fuel rail of my M135GX was 31,200 psi. We ran a wear test between Denso, Bosch, and a third supplier and learned Denso was far better than the rest (about 10 years ago). It some explanation as to why parts are hard to rebuild to the quality needed. And in testing common rail equipped engines, I ended up with a half dozen worn injectors sitting on my failed part display in my office. During testing I’d hear from a test user their machine wouldn’t build enough pressure to start so I’d send them a new injector set and warned them about bad fuel. To me, our engine division kept sending me injectors and the cost didn’t come out of my budget. I didn’t know those little things were over $1,000 a pop. Those were the third party injectors by the way, not Denso.

 

[Like Tractors]

As you probably know, a heavy duty hydrostatic pump is good for about 6500 psi and a Denso common rail pump can hit relief at 30,000 psi. So we’re talking super close clearances and tight tolerances. That’s why filtration has become more important. Our old 1939 TD6 International injection pressure was 1650 psi, my old L5740 max injection pressure was 2130 psi, and the relief valve on the fuel rail of my M135GX was 31,200 psi. We ran a wear test between Denso, Bosch, and a third supplier and learned Denso was far better than the rest (about 10 years ago). It some explanation as to why parts are hard to rebuild to the quality needed. And in testing common rail equipped engines, I ended up with a half dozen worn injectors sitting on my failed part display in my office. During testing I’d hear from a test user their machine wouldn’t build enough pressure to start so I’d send them a new injector set and warned them about bad fuel. To me, our engine division kept sending me injectors and the cost didn’t come out of my budget. I didn’t know those little things were over $1,000 a pop. Those were the third party injectors by the way, not Denso.

During your testing of common rail diesel pumps, did you study the effect of low fuel supply pressure and fluid dynamic cavitation on the pumps? I test common rail diesel pick ups, the systems with no fuel supply pump do have more fuel system failures. I had a Kubota M7060 that had fuel system/low power and misfire problems that started at about 50 hours. As it turns out those tractors run with very little if any fuel supply pressure to the high pressure pump. My M7060 would measure a negative fuel pressure at the filter inlet under load. My friendly Kubota dealership replaced it with an M5-091.

 

[MHarryE]

During your testing of common rail diesel pumps, did you study the effect of low fuel supply pressure and fluid dynamic cavitation on the pumps? I test common rail diesel pick ups, the systems with no fuel supply pump do have more fuel system failures. I had a Kubota M7060 that had fuel system/low power and misfire problems that started at about 50 hours. As it turns out those tractors run with very little if any fuel supply pressure to the high pressure pump. My M7060 would measure a negative fuel pressure at the filter inlet under load. My friendly Kubota dealership replaced it with an M5-091.

No, my responsibility was validating the machine for production. Engine Division was expected to give us a proven product. During validation for common rail introduction at Tier 3, I opted to change from design to validation. I had a fleet of about 4 pre-production machines to run hours at our proving grounds and another 20 machines located with customers around the world. We just had to supply a line from the tank to the engine and engine division took it from there so preventing damage due to no fuel - line blockage or running out of fuel - we depended on engine division to handle that. The major problem I found, and my counterparts at other product groups, is that fuel really sucks no matter where in the world you might be. And venting a fuel tank - needs to be as fine as the system as working in a dusty environment can end up overloading the filter system quickly unless the vent is filtered.

My M7-171 spits out an error code and drops to an idle if the rail pressure drops. Chart says contact dealer. Dealer says, like I suspected, change filters. Filter replacement interval is 400 hours but I never reach that due to drop in rail pressure. Then it’s limp home as it work okay after a restart until you draw so much power it once again can’t maintain enough flow.

 

[Like Tractors]

No, my responsibility was validating the machine for production. Engine Division was expected to give us a proven product. During validation for common rail introduction at Tier 3, I opted to change from design to validation. I had a fleet of about 4 pre-production machines to run hours at our proving grounds and another 20 machines located with customers around the world. We just had to supply a line from the tank to the engine and engine division took it from there so preventing damage due to no fuel - line blockage or running out of fuel - we depended on engine division to handle that. The major problem I found, and my counterparts at other product groups, is that fuel really sucks no matter where in the world you might be. And venting a fuel tank - needs to be as fine as the system as working in a dusty environment can end up overloading the filter system quickly unless the vent is filtered.

My M7-171 spits out an error code and drops to an idle if the rail pressure drops. Chart says contact dealer. Dealer says, like I suspected, change filters. Filter replacement interval is 400 hours but I never reach that due to drop in rail pressure. Then it痴 limp home as it work okay after a restart until you draw so much power it once again can稚 maintain enough flow.

I suggest to anyone with a late model diesel engine equipped tractor, test fuel supply pressure to the high pressure pump and verify that there is positive pressure when running under full load to avoid fluid dynamic cavitation in the high pressure system. I believe the supply pressure for testing common rail pumps is in the 10 PSI area, a pre 2017 Duramax runs with around a negative 5.0" Hg fuel pressure and their systems suffer the most in the diesel pick up industry. The other manufacturers run with positive fuel pressure. The Kubota M7060 runs with a negative supply pressure under full load, the M5 runs with about 2 psi and an M6 is also running with about 2 psi under full load, they should all be above 5 psi to help avoid cavitation. Fuel lubrication is another important factor to avoid failure, ASTM specs call for a certain level of lubrication since we went to ultra low sulfur fuel for the 2007 compliant on highway diesel engines, but not all fuel suppliers are the same. Fuel filtration speaks for itself, common rail systems have filters in the 2-5 micron area, don't pour fuel down the center of the filter!

I suggest to the owner of the subject tractor, once the repair is done, test supply pressure and if it isn't above 5 psi at the filter inlet, make some corrections in order to get good service life out of the repair.