B7100 Restore Project Has Begun

[NIdaho]

Hey guys,

Here is a link to my old B7100. The transmission went out in it several years ago and I sold it as a "mechanics Special" to a local diesel mechanic that was going to fix it and resell it. Unfortunately when he cracked the tranny open it was a lot worse than he thought and he is now parting it out. The engine ran great when I sold it to him.

He has the complete engine on Craigs List for $550.
kubota engine parts

here is the link to the rest of the tractor
B7100 kubota

 

[j t huskins]

Thanks to all of you who have given information and links to parts. I will keep them in mind if needed. As of now I have invested 665.00 in engine parts and will have a nearly new engine if all goes well with the rebuild. Thankfully the block and crank were both machinable. May need other parts for the machine as the restore progresses. 550.00 for a good running engine is a steel when you compare the cost of little orange parts. My small box of gold arrived today from Messicks. They were very prompt with shipping and everything came as ordered. Its hard to believe that 665.00 worth of engine parts can fit in such a small box. As you can see from the pic the orange tractor parts were disguised in a CNH parts box.

 

[Martian]

Thanks to all of you who have given information and links to parts. I will keep them in mind if needed. As of now I have invested 665.00 in engine parts and will have a nearly new engine if all goes well with the rebuild. Thankfully the block and crank were both machinable. May need other parts for the machine as the restore progresses. 550.00 for a good running engine is a steel when you compare the cost of little orange parts. My small box of gold arrived today from Messicks. They were very prompt with shipping and everything came as ordered. Its hard to believe that 665.00 worth of engine parts can fit in such a small box. As you can see from the pic the orange tractor parts were disguised in a CNH parts box.

One step closer. Do remember seeing Messicks sold New Hollands but it is kind of funny that they would send Kubota parts in a CNH box

 

[5030]

Got my head, block, and crank to the machine shop yesterday. Good news so far. The cylinders are good for a .5mm bore and the crank will just get a polish. Ordered 675.00 worth of parts from Messicks just to get the machine work going and put the bottom end back together. Thankfully I obtained this tractor very cheap on a NC sealed bid so I have a lot of room to spend before I exceed the value. Hopefully I will have a like new tractor for the same money that I would have paid retail for one then had to make repairs. As for the wheel weights, the tractor has front and rear factory weights. With the FEL being plenty of weight for the front I am considering not using the fronts if the restore continues. The tires have never been loaded with fluid so my wheels should be in good condition. Spent 4 hours washing engine parts spic and span to prepare for a restore paint job as I re assemble. Will have to get the engine going before I will know what else needs repair besides the charging system which was the reason for the tractor being taken out of service.

Couple interesting points here...

10 or 15 Kubota's ago, a B7100 was my very first Kubota tractor. I had turf tires and it was 4wd. Great little and very handy machine. I should have kept it...

I do, however, still have the Kubota full shop manual (in the orange 3 ring binder) on the shelf if you need one. It's in pristine condition.

Finally, the 7100's didn't have a charging system per 'se. They used a permanent magnet 'dynamo', belt driven in front of the water pump and a diode type voltage regulator. Enough to keep the battery up and power the (rather crude and dim) lights.

Mine had a translucent plastic fuel tank under the hood, behind the engine and it sprung a leak and had to be replaced, I believe that was the only defect.

 

[chrisjbell]

I ended up finding a D950 in an Onan marine diesel generator that was in fine shape for a good price, so swapped a few parts (heh heh) and how have a 20hp D950 (with a real waterpump!) powering my B7100. It's been a great tractor.

Those old Kubotas are rock solid. Its amazing how much abuse the Kubota diesels can take - a lot of golf course equipment uses them. I took an engine out of a triplex mower that was falling apart around it and put it in a utility cart... worked great, was a painless swap. Never did rebuild one - I'm curious to see how that goes...

 

[Leejohn]

I could find 2 of them. One is a 12 tooth, O.D. is 1.360 and the stub is 3.150 long. It has a I.D. of .700 with a 22 spline.
The other is a 22 tooth with a stub that is 1.450 long. It also has the 22 spline I.D. of .700.
I read on here that the 22 spline was hard to match up, I never tried. I was wanting to put a front PTO on my B7800, but the front pully isn't made to take the stub shaft. Sure wish I could find out for sure if another pully would work or not.

 

[RobertN]

I noticed that too Hehehe...

As a previous Kubota guy, now NH guy, thought that was funny! Course, I still like Kubota's...

One step closer. Do remember seeing Messicks sold New Hollands but it is kind of funny that they would send Kubota parts in a CNH box

 

[6mmbr]

I have my "new to me" B7100 arriving tomorrow so I am following this thread with interest. It does have an oil leak at head gasket but I'm afraid that implies a cracked head. (I will be looking for bubbles in the radiator as soon as I can get it unloaded). Will be doing some investigating and following your rebuild.

My question is: What other Kubota engines will fit in the B7100hst frame without severe modification? I read above a 950 will fit, others?

Thank you

 

[petes]

I have my "new to me" B7100 arriving tomorrow so I am following this thread with interest. It does have an oil leak at head gasket but I'm afraid that implies a cracked head. (I will be looking for bubbles in the radiator as soon as I can get it unloaded). Will be doing some investigating and following your rebuild.

My question is: What other Kubota engines will fit in the B7100hst frame without severe modification? I read above a 950 will fit, others?
Thank you

D750, D850 and D950 all have the same block and should drop in/bolt up. I can't remember if a D650 is the same or not. The Kubota/Onan marine generator D950 I used had a larger diameter flywheel, different starter motor, deeper oil pan and pickup tube, different front cover (oil filter on the opposite side, requiring fabricating a remote filter mount) and as I stated above, a waterpump instead of the "percolator" in the original B7100 D750. The waterpump had different size and location for the hose connections requiring some plumbing creativitity. Flywheel and oil pan swapped for my old ones, and I decided to live with the front cover... couldn't come up with an easy way to swap that due to the waterpump differences. Oh, and I had to make a front PTO shaft to bolt to the front pulley (and went with a 5/8" key'ed shaft instead of spline). From what I'd been able to determine, all other Kubota blocks are different.

Sources for D750/850/950 engines: Marine propulsion engines: Universal M25XP = Kubota D950. Whatever Onan marine diesel generator gave mine up. Some trailer mounted highway construction lights use D750's.

Good luck!

 

[j t huskins]

Waiting patiently on my machine shop to do their thing. Trying to design a way to install a temp gauge since the head does not have any ports. Thinking of maybe making an aluminum sleeve that can be inserted into the top radiator hose with a 1/8 PT fitting welded in it. Will be placing a tee at the oil pressure light port to install a oil pressure gauge.

 

[j t huskins]

I have my "new to me" B7100 arriving tomorrow so I am following this thread with interest. It does have an oil leak at head gasket but I'm afraid that implies a cracked head. (I will be looking for bubbles in the radiator as soon as I can get it unloaded). Will be doing some investigating and following your rebuild.

My question is: What other Kubota engines will fit in the B7100hst frame without severe modification? I read above a 950 will fit, others?

Thank you

What area of the head is the oil coming from? The pressure port for head lubrication is located just above the oil pressure light sending unit on the left rear of the engine. This port is sealed with a O ring that is seperate from the head gasket.

 

[6mmbr]

Yes it is coming from the area around the sender unit. It was replaced by the previous owner to no avail. The concern is though the amount of JB Weld smeared around this area! I suspect bad things! ha!.

Anyway, have another engine being delivered on tuesday so I will do some investigating and put best one in. Separated the back end of the tractor today (working from back to front). Found bad U-joint for 4x4 shaft I will replace. Hydrostat linkage was misaligned preventing it from returning to neutral position (been that way for years obviously) which I will fix and improve on the original design. Tomorrow will separate the bell housing from engine and see what exciting things I can find there.

I saw another forum post here where water temp gauge is placed in radiator hose. Query on eBAy: "Water temp Gauge Radiator Hose Sensor Adaptor" and you will find the key component. I don't know the diameter of the hose yet (working back to front).

thanks
jeff

 

[Tachdriver]

Plenty of places for a Temperature sender. Since you are in rebuild, maybe a freeze plug is available to weld a coupling onto


later

 

[j t huskins]

Yes it is coming from the area around the sender unit. It was replaced by the previous owner to no avail. The concern is though the amount of JB Weld smeared around this area! I suspect bad things! ha!.

Anyway, have another engine being delivered on tuesday so I will do some investigating and put best one in. Separated the back end of the tractor today (working from back to front). Found bad U-joint for 4x4 shaft I will replace. Hydrostat linkage was misaligned preventing it from returning to neutral position (been that way for years obviously) which I will fix and improve on the original design. Tomorrow will separate the bell housing from engine and see what exciting things I can find there.

I saw another forum post here where water temp gauge is placed in radiator hose. Query on eBAy: "Water temp Gauge Radiator Hose Sensor Adaptor" and you will find the key component. I don't know the diameter of the hose yet (working back to front).

thanks
jeff

Thanks, found them. Mine is 34mm. Didn't realize that my idea was already in production.

 

[bigdad]

Thanks to all of you who have given information and links to parts. I will keep them in mind if needed. As of now I have invested 665.00 in engine parts and will have a nearly new engine if all goes well with the rebuild. Thankfully the block and crank were both machinable. May need other parts for the machine as the restore progresses. 550.00 for a good running engine is a steel when you compare the cost of little orange parts. My small box of gold arrived today from Messicks. They were very prompt with shipping and everything came as ordered. Its hard to believe that 665.00 worth of engine parts can fit in such a small box. As you can see from the pic the orange tractor parts were disguised in a CNH parts box.

I pucker up any time I see those orange and blue boxes. Even the ones that have the filters in them.

 

[j t huskins]

Finished ordering the gaskets from my local dealer yesterday. Still waiting on the machine shop. Wanted to get it together during the Christmas holiday but its not looking good. Bought an automotive choke cable and made a compression release cable to replace the factory one that was stuck. Have all the plumbing to hook up a OP gauge and will be ordering one of the radiator hose adapters to hook up a temp. gauge. Painting my front frame and axle while it is apart and cleaned. The radiator is going to the shop to be cleaned, pressure tested, and repaired if needed.

 

[j t huskins]

Picked up my pieces from the machine shop on Wed. and got to work. Checked piston skirt and ring end gaps and got the pistons installed. Bearing clearances all checked good. Got the bottom end together by Wed. night. Started early Thur. morning and finished the reassembly and painting. Bolted it up Thur. night. Rolled the front axle and frame into place Fri. morning and made all of the hookups. Fired it up Fri. night. Posted video of the fire up after bleeding the fuel system but the audio did not load so there is no sound. It purrs like a kitten. 40 PSI oil pressure reading on the manual gauge that I installed. Took it out on Saturday to begin the break-in. Now I can find out what kind of shape the tractor is in. Gear noise is more than I like to hear in 4th and 5th gears and is worse in 4wd. Lift works good but leaks down if left up for an extended time. Rear hubs are worn which I already was aware of but didn't know how it would affect the tractors performance.













View attachment 244394

 

[j t huskins]

Now comes the rest of the restore. Going to break it apart and inspect the gears to try and locate the source of the noise.

 

[General Lee]

That is coming along nicely. Last year I bought a 1978 B7100 in operating condition and planned on doing *some* restoration on it. The urge faded and I got rid of it. Kinda wished I still had it.

 

[6mmbr]

WOW! that is a gorgeous engine. There is no greater satisfaction than rebuilding an engine and having it fire right up and "purr like a kitten". Not everybody can do that and you've got to give yourself a lot of credit. I like the pictures. I can almost smell the oil and feel the plastigauge! I hope I am as lucky as you are skilled when I get to heating up the glow plugs for the 1st time!

Ugh. Sorry about the gear noise. The rear is a little more daunting for me because I know its all about replacing not rebuilding. A full line of bearing separators and a little hydraulic press can be worth their weight. Hopefully you can find a simple "junkyard problem" = "one bad dog with a broken tooth".

Did you have any metal on the sump screens?

- saw your note on the pipe thread - glad you have good resources.

Good luck. I will be watching with interest.