Crank seized B7100D

IdahoNative

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Kubota B7100D 4x4, non-HST, FEL 1630
Jan 12, 2022
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I posted "flywheel seized" last week. Suggestions were made to check the crank, so I strapped the crank pully...it would not budge.

As I stated in my first post, I recently purchased a B7100D. I replaced every fluid, it did not burn oil and the radiator stays full. I put about 36 hours on it. I was back-dragging sand in low, just crawling along. Heard a loud "snap" that appeared to come from the front right side of the engine. But I had hearing protection on, so who knows. It instantly shut down. No other noises or smells. Turn the key, and "thunk". Removed the starter and tried to rotate flywheel with a prybar. It didn't move. I can push it forward and backwards in any gear (all have the same level of resistance, not much) and neither the crank or flywheel moves. Neither one of those sounds normal.

I have no idea where to start.

If anything behind the flywheel failed catastrophically, I think the crank would still turn over, right?

If so, the problem is ahead of the bellhousing, right?

I pulled the valve cover off. Nothing exciting with the rocker arm, springs, etc. They all feel and react "normal". Should I pull the rocker assembly and push rods ad see if one is bent?

If I was correct that something snapped near the front right, could something have snapped in the injection pump cam shaft system that would seize the engine components?

Or should I keep going on the top, remove the head next to check for bent valves?

Dropping the oil pan is obvious, until I looked below. Looks like the front diff needs removed and perhaps the loader cross member.

Input is greatly appreciated.
 

Chanceywd

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Many years ago I went out this time of year to start my truck. It ran for a second quit and then wouldn't turn over to start. I know it isn't the same but I tried jumping, I tried a bar on the crank nut but it wouldn't move. I could see some deflection in the serpentine belt so I loosened that and then it would turn. It then started. What I then found it was the power steering pump set up solid and i replaced that.
So i am wondering if it could be the injection pump or hydraulic pump has set up. Just a passing thought from someone who has engine experience but not strong on diesels. Don't know what is involved with pulling them free to see.

Bill
 
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Henro

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Are you keeping the clutch pedal depressed when you are trying to rotate the engine crankshaft?

Can't help but think if not, even if in neutral, if the transmission was locked up for some reason, perhaps that is what is preventing the rotation of the crank, IF you are not depressing the clutch pedal, to break the mechanical connection between the transmission and the crank.

Just a thought...

Edit: But I guess you would depress the clutch when trying to start the engine, so a locked up transmission is unlikely the issue...
 

GSD-Keegan

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yes, make sure any accessory running from fan belt is not seized. Best to remove any drive belts.

You might consider draining part, or all of the oil into a clean drain pan and examine the oil for particles? And/or thru a strainer or filter of some sort.
 
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85Hokie

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Drain the oil and see if you have chunks of metal.
A cheap refridge magnet will help with this too, drop it in the container and swish around - pull out and examine.
 
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IdahoNative

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Kubota B7100D 4x4, non-HST, FEL 1630
Jan 12, 2022
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Florida, central
Are you keeping the clutch pedal depressed when you are trying to rotate the engine crankshaft?

Can't help but think if not, even if in neutral, if the transmission was locked up for some reason, perhaps that is what is preventing the rotation of the crank, IF you are not depressing the clutch pedal, to break the mechanical connection between the transmission and the crank.

Just a thought...

Edit: But I guess you would depress the clutch when trying to start the engine, so a locked up transmission is unlikely the issue...
[/
Are you keeping the clutch pedal depressed when you are trying to rotate the engine crankshaft?

Can't help but think if not, even if in neutral, if the transmission was locked up for some reason, perhaps that is what is preventing the rotation of the crank, IF you are not depressing the clutch pedal, to break the mechanical connection between the transmission and the crank.

Just a thought...

Edit: But I guess you would depress the clutch when trying to start the engine, so a locked up transmission is unlikely the issue...
I did not depress the clutch while trying to turn the crank, but your edit makes sense. Regardless, I’m gonna try it with clutch depressed.
Thanks for your input.
 

85Hokie

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I did not depress the clutch while trying to turn the crank, but your edit makes sense. Regardless, I’m gonna try it with clutch depressed.
Thanks for your input.
Place a block UP under the pedal .......... no need to have another person ;)
2015-06-28 12.59.35.jpg
 
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IdahoNative

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Bill,
Thanks for the reply. I removed the belt, so nothing (ie water pump) else can influence the crank rotation.
I do have the shop service manual. I’m gonna see how the injector pump is activated. Not sure if it has a timing chain or gear to gear connection with the crank. As I am responding to you, I realized it acted just like a timing chain snapping on a gasser. A “snap”, sudden engine stop and starter thunking. I’ll check for metal in the oil then study the schematics of all the symptoms. Hopefully I can see a weak spot….
 

North Idaho Wolfman

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Drop the front frame/ axle/ and propeller shaft and drop the pan.
Sounds like you might have a broken rod, or maybe just a seized bearing.

The timing is all done with gears, in all my years of working on these I haven't seen the gears ever fail.

There is one other remote possibility, and that it the hydraulic pump is seized, it's attached onto the back of the fuel cam.
 
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Jim6100

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It’s a longshot but if your front and loader is operated by a front PTO pump possibly it has locked up try uncoupling it and see if it will rotate
 

IdahoNative

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Kubota B7100D 4x4, non-HST, FEL 1630
Jan 12, 2022
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Florida, central
Northern Idaho Wolfman,

Thank you for your reply.

My son and I just took the head off, and carefully pulled the injector pump along with the front plate at the end of the fuel cam shaft. Like you indicated, it looked great. No metal pieces, no marks on the gears…clean as a whistle. Valves and push rods good too. I drained the oil and no shavings were found. We are going to pull the motor and drop the pan.

I looked at the piston position. The front piston top was 2.75” from the deck, middle piston was 0.75” and the rear at 1.125. I would think they should be proportional to each other. Am I overthinking it? If so, it’s U of I’s College of Engineering fault.

Interesting you mentioned the hydraulic pump. My son thought there was a possibility of it being the culprit. If it is locked up, should the motor turn over if we unbolt it from the fuel cam assembly?
 

IdahoNative

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Kubota B7100D 4x4, non-HST, FEL 1630
Jan 12, 2022
114
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Florida, central
Jim,,
My loader is controlled by the fuel cam. But Northern Idaho Wolfman mentioned there’s a slight possibility it is locked up.
 

IdahoNative

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Kubota B7100D 4x4, non-HST, FEL 1630
Jan 12, 2022
114
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Florida, central
Yes unbolt it and see if it or the motor turns.
Well, I finally split my tractor tonight…and found at least one pressure plate finger snapped and bound up the flywheel, which locked up the crank. The crank turns now. Whew! Gonna replace the clutch, P plate, TO bearing, pilot bushing, and perhaps have the flywheel turned. Wish me luck!
 
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North Idaho Wolfman

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Well, I finally split my tractor tonight…and found at least one pressure plate finger snapped and bound up the flywheel, which locked up the crank. The crank turns now. Whew! Gonna replace the clutch, P plate, TO bearing, pilot bushing, and perhaps have the flywheel turned. Wish me luck!
Good to hear you found out what stopped it.
Not a real expensive fix.
 
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IdahoNative

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Kubota B7100D 4x4, non-HST, FEL 1630
Jan 12, 2022
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Florida, central
Good to hear you found out what stopped it.
Not a real expensive fix.
Thx!
And I split it without removing the loader. I lowered the bucket and placed jack stands under the loader frame (near the foot pads). Removed the required stuff, slid a floor jack under the rear “cross member”, removed the frame bolts, and pushed/wiggled the rear half backwards….took about an hour.

The input shaft feels a bit loose, gonna check it tomorrow.

Any advice on the install? I read about indexing the crank/flywheel. Otherwise, it looks similar to replacing the clutch on a ‘60s car.
 

North Idaho Wolfman

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Easier than a 60's car!
Replace the pressure plate, clutch disk, throw-out bearing, and pilot bushing.
Pull the input shaft off of the front of the transmission and check that coupling to make sure it's good.
 
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Chanceywd

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Easier than a 60's car!
Replace the pressure plate, clutch disk, throw-out bearing, and pilot bushing.
Pull the input shaft off of the front of the transmission and check that coupling to make sure it's good.
On the 60's car you could have dropped a metal shield and possibly seen the clutch damage early on. These tractors need some kind of inspection hole or access. It could have saved the OP a ton of time.
Bill
 
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North Idaho Wolfman

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On the 60's car you could have dropped a metal shield and possibly seen the clutch damage early on. These tractors need some kind of inspection hole or access. It could have saved the OP a ton of time.
Bill
These tractors were designed to work in rice paddies so access holes, plates and ports would have just leaked.
 
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