M5400 hydraulic pump worth rebuilding? Available seal kits?

old_haidouk

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Kubota M5400
Feb 13, 2022
17
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Houston, TX
I took off the pump yesterday and upon disassembly and examination I can't see any metal parts damaged or heavily wore out. Thinking it might just be the seals that need replacing. Anyone has any experience with these pumps? Also I can't figure out the model number or new or old type, it only has a 332 3000 000 on the back cover.
 

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TheOldHokie

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I took off the pump yesterday and upon disassembly and examination I can't see any metal parts damaged or heavily wore out. Thinking it might just be the seals that need replacing. Anyone has any experience with these pumps? Also I can't figure out the model number or new or old type, it only has a 332 3000 000 on the back cover.
The only seals in a gear pump are shaft and case seals. If its not producing pressure the oil clearances are worn oversize and the pump is scrap metal.

Dan
 
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kubotafreak

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I would look over the suction line of the system well. Air ingress can cause similar issues.
 
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TheOldHokie

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I appreciate the input. Do you know of any specific, vulnerable points that I should check on the intake?
Looking at the parts diagram not much to go wrong there. Basically two lengths of steel tube and half a dozen orings. Unfortunately the easiest way to evaluate supply is flow at the output side of the pump and you pretty much burned your bridges when you took it apart.

New aftetmarket pump is $750. I am not a fan of shooting in the dark but given the symptoms and situation I'd say pull the trigger.

Dan
 
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kubotafreak

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35890-12970 seal kit for the pump(new)
pump.PNG


Any crack or seal in that lower hard line #70/#40 or around the filters.

Look for leaks...
 
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rbargeron

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The clearance in the pump gears is very small - and the velocity of the oil at the tips that's actually try to flow backward is high. ANYTHING suspended in the oil (microscopic particles) acts to wear the gear tips away. The M5400 is a gear tractor so you could try using heavier-weight oil but the difference is never dramatic. Replacing the pump is the only solution likely to make the difference you want. Give the new one new oil and filter so it starts its life in a good environment.
 
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TheOldHokie

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The clearance in the pump gears is very small - and the velocity of the oil at the tips that's actually try to flow backward is high. ANYTHING suspended in the oil (microscopic particles) acts to wear the gear tips away. The M5400 is a gear tractor so you could try using heavier-weight oil but the difference is never dramatic. Replacing the pump is the only solution likely to make the difference you want. Give the new one new oil and filter so it starts its life in a good environment.
Not just the gear tips - the housing is softer and wears as well. I came up with an inexpensive gear pump retrofit for old Ford tractors and have dozens of very happy customers that wasted many hours and lots of money trying to rebuild the OEM pumps with new gears, pistons, vanes and rotors. DFW because the housings are worn oversize.

About the only thing worse than particulate contamination for hydraulic pumps is oil starvation. Both are untreatable and usually fatal.

Dan

PumpConversionKit1.jpg
 
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old_haidouk

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Kubota M5400
Feb 13, 2022
17
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Houston, TX
Thank you all for replying. The Hydraulic oil was heavily contaminated with water which probably contributed to the pump wearing out. I ll get an after market pump.
 

North Idaho Wolfman

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Did you loose steering too?
Did the steering become hard when the hydraulics went out?
Contaminated fluid will do just what your explaining with out the pump having any issues.
I personally if seeing no obvious heavy wear on the pump would put seals in it with new filters and new fluid.
 
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TheOldHokie

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Did you loose steering too?
Did the steering become hard when the hydraulics went out?
Contaminated fluid will do just what your explaining with out the pump having any issues.
I personally if seeing no obvious heavy wear on the pump would put seals in it with new filters and new fluid.
I cant tell you how many times I have heard that story.

In any event if thats the old style pump Messicks says the seal kits are discontinued.

Dan
 

kubotafreak

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It would appear he has the newer style pump going off the pictures uploaded.
 

fried1765

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Not just the gear tips - the housing is softer and wears as well. I came up with an inexpensive gear pump retrofit for old Ford tractors and have dozens of very happy customers that wasted many hours and lots of money trying to rebuild the OEM pumps with new gears, pistons, vanes and rotors. DFW because the housings are worn oversize.

About the only thing worse than particulate contamination for hydraulic pumps is oil starvation. Both are untreatable and usually fatal.

Dan

View attachment 106203
Does your Ford aftermarket pump fix work for the Ford/Shibaura tractors?
 

TheOldHokie

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Does your Ford aftermarket pump fix work for the Ford/Shibaura tractors?
No. Its a replacement for 1953-1964 Ford NAA Hundred,, and early One/Two Thousand series tractors with the OEM vane or piston pumps. I did one for a later 3000 series tractor but the plumbing on it is a royal B to hook up. Interestingly that was a one off for a Kubota dealership and the owner got me interested in the L3901 which I eventually wound up buying.

Dan
 

fried1765

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No. Its a replacement for 1953-1964 Ford NAA Hundred,, and early One/Two Thousand series tractors with the OEM vane or piston pumps. I did one for a later 3000 series tractor but the plumbing on it is a royal B to hook up. Interestingly that was a one off for a Kubota dealership and the owner got me interested in the L3901 which I eventually wound up buying.

Dan
Thanks!
 

old_haidouk

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Equipment
Kubota M5400
Feb 13, 2022
17
6
3
Houston, TX
Did you loose steering too?
Did the steering become hard when the hydraulics went out?
Contaminated fluid will do just what your explaining with out the pump having any issues.
I personally if seeing no obvious heavy wear on the pump would put seals in it with new filters and new fluid.
Steering was partly lost. The wheel jerks when I steer more than 30 degrees from straight.
 

TheOldHokie

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Thing is an aftermarket pump on ebay is around $400. Made in China but beats the 2k plus on Messick.
You are preaching to the choir. I thought I had expressed my opinion pretty clearly.

New aftetmarket pump is $750. I am not a fan of shooting in the dark but given the symptoms and situation I'd say pull the trigger.

Dan
I would have had a new aftermarket pump ordered days ago.

Dan
 
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