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It's ALIVE!! Nothing sounded better than that thump thump thump sound resonating from the belly of the 720 beast!! After nearly 4 months of repair, sweat, some blood, and maybe even cursing the tractor is running a driving. About the only major problem I encountered after firing it up was a steady stream of oil from underneath the platform. I discovered a very bad leak on the high pressure hydraulic supply line. I had a repair shop patch it with some more modern materials...but it's discreet and you cannot see it underneath the platform. Other than a few fuel leaks the tractor seems to run great! I got a nice wide front axle under it and some new 7.50x16" Firestone 3-rib tires and it looks much better...although it doesn't turn nearly as short as the roll-a-matic.

I used it with a rear bale carrier to move about 10 bales of hay just to give it a try and it worked great! Hopefully I'll get time to swap the rear tires with some better treaded ones.

Most recent photos added 9-6-06 (hover your cursor over the picture to see a text message)

I'm sure glad that I decided to check the seal on the pony motor water pump!! It turned out that it had been leaking quite badly into the pony crankcase. A couple of new seals and a bunch of silicone sealer and we're ready to go. I tested the thermostat and it works just like it should. We now have the pony motor on the tractor, all fluids have been topped off. I ran one tank of fuel through the pony motor but it didn't seem to run quite right. Well, come to find out it was running on only 3 cylinders. I'm going to bite the bullet and buy a pony ignition tune up kit. There are several pictures of the pony motor fuel shut-off assembly along with the cut out switch for the ignition power when the oil pressure drops below 5-p.s.i. I looked all over for a suitable valve for the manual fuel shut-off from the dash but found none worth using. JD still has the part available but the valve has a turn handle so it would require a decent amount of modification plus it costs $25 or so. I kept thinking that I've seen a similar valve somewhere before....but where and what. Well, as I was looking through the plumbing isle at the hardware store, I remembered that the little saddle valve which you would use to tap into the water pipe for an icemaker just might work. Sure enough, the valve would work with very little modification. I just had to remove the needle and handle cross and lengthen the control rod about 3/4" of an inch. It's installed and works like it should...and all for only $4.99! Once we get the pony motor running right again I'll go ahead and install the diesel fuel tank and see what happens. I'm hoping that bleeding the system isn't as difficult as I've heard it is. I've still got to get a few parts like a pony motor starter switch (you might notice the toggle switch in the dash panel...ugly!! but only temporary)

I have been slacking some on the 720 as we are nearing completion. The head, block, pistons, fuel injection pump, governor, fan shaft, timing gears, timing cover, new used reduction cover, and the clutch are all back in the tractor. I got some spark plugs for the pony motor today so that I'll have a fresh start. I checked the coils last week and both of them throw a nice blue spark! I'm just keeping my fingers crossed that it will run good enough not to have to pull it apart and that there won't be any oil leaks. I've got a new tachometer and temp gauge to install along with making sure the lights work. The rest is just timing and putting on the flywheel. I'm sure that Teresa's dad will kindly oblige my need to plow with some of his best 'GUMBO' Mississippi river bottom soil when the time is here to seat those rings.

Great news as we got the pony motor running!! It ran quite good so we're going to put some seals on it and set her on the 720. The flywheel is back on and tight with .006 endplay. We replaced the load control shaft oil seal and inspected the bushings/shaft...everything was super clean and very little wear was visible. We filled the transmission/reduction cover/rear end with 90wt mineral oil. The clutch is properly adjusted with those pesky little stop adjusters on the late 20 series and 30 series being the major time consuming process there. I brushed the battery box with rust converter and dad fabricated a reinforcement at the top of the box using 1/8" x 3" flat stock steel. Things are going along good and we hope to get it running soon.

I got back to work on the 720 after taking a short float/camping trip over the weekend. Alex and Teresa were there helping me this time. Alex and I removed and cleaned the oil pump. We got all of the dirt and crud out of the crankcase and put it all back together. New gaskets and plenty of that nasty 'orange' permatex will hopefully keep the oil were it needs to be. I reinstalled the R.H. main bearing housing and then heated up the PTO drive gear and slid it on the crankshaft. Teresa wanted to help out so I got the air powered die grinder with the sanding/cleaning disc attachment. The timing gear cover was covered with dirt and the gasket mating surfaces were rusty. She put on the saftey glasses and went to town working on it and after about 1 hour it would be ready to go on the tractor....now all I have to do is get the rest of the stuff behind the cover ready to go. I rebuilt the water pump with the help of Marvin's press and now it has a nice thick coat of JD green paint and turns over really nice. We were going to install the engine block...but realized that we had no block to main case gasket. Oh well, maybe I'll get the other 2 camshaft lifters that I need so that the cam, cam followers, and fuel injection pump followers can go in before the block.

Things are still going on strong with reassembly. Alex and I worked until midnight in the air conditioned shop while it was 80 deg and muggy outside. The pistons are back in the block and all ready to go. It took some time, but we got all of the governor parts cleaned up and ready to be set up. It took a new 1st reduction cover to help me sleep at night as the old one had a pretty bad crack which was repaired quite sometime ago, but was again broken. My mom and dad took off last week on a garage sale / antique shop expedition taking them through NE Indiana. I gave in and paid Polk's price to have a good part...besides I was having no luck finding one otherwise. I am hoping to tackle the pony motor very soon and I realize that I can't just keep putting it off. I used the rebuilt water pump on a 720lp standard which needed one and just complete the rebuild on the LP's pump so with a coat of paint it will be ready to go on the diesel.

Alex and I have the transmission back together not and the tractor is in one rolling unit once again. We tightened the castlated nuts for the axles as the endplay was a little too much before bolting it back together. I've got the power steering, hydraulic, and diesel fuel transfer pumps rebuilt with new bushings, seals, ect. I got a set of 4 smaller seals from 2-Cylinder Plus in MO for the transfer pump. The idea is that 4 seals running on different spots in the drive shaft is better than 2 from JD running on the same 2 worn places on the shaft. We'll see how well it works hopefully soon. The head is ready to go on as well as the block. It took a lot of grinding, but I ended up using 830 valves in the 720 head to hopefully help the engine breathe better. The exhaust ports are polished for better air flow as well. The injectors & pump should be back soon from Roy Ritter in MO. The camshaft is back from Roberts Carburetor after being ground. UPS is still supposed to compensate me for the 3 cam followers that never made it to Iowa for surfacing. I replaced the oil seal on the crankshaft and still have to put in all back together. I got a nice used matching 15.5-38" Goodyear wavvy tread tire at an auction for $100 so I'll have to get that changed out sometime. I keep my fingers crossed that the pony motor will just fire right up and need nothing more than a tune-up. We'll have to see about that. More pictures above.

6-18-06

Well, things are really moving along. I've got the tractor split apart and have the transmission completely disassembled. I managed to do this without completely disassembling the shifter shafts (except for the 6th gear)! All of the pawls and springs felt good before I tore into the beast so it's going to stay that way. I managed to find a few bad bearings. The ball and roller bearing in the main housing for the PTO need replaced, but it would appear that the PTO quill assembly is tight and maybe it was rebuilt? The LH outer race for the differential has a bad spot as you can see in the photo gallery. The infamous New Departure 1213-S upper shaft LH bearing at first appeared shot. But after some cleaning and spinning out it turns great and it is tight so thank goodness! All of the gears are in excellent condition so no problems there. I removed the RH main bearing housing and there is some wear on the crankshaft and main bearing insert, but it was within specs when I put the dial indicator on it. There are grooves where the oil seal was running on the crank so hopefully I can position the new oil seal where it won't ride in the same spot as the old one. I'm tempted to replace the PTO input shaft seals while I'm right there but will have to see about that one.

Click HERE to see photos from 6-18-06

The cylinder block and cylinder head are at the machine shop. The block cleaned up for .045 oversize pistons. The head checked out okay and it's going to get a valve job with the help of my friend Marvin. I cringed at the thought of spending $600 on a new aftermarket set of diesel pistons...but then I found a good set of used .045 oversize original JD pistons out of a 70 diesel parts tractor.

The camshaft looks quite worn and shows some nasty wear on the #2 fuel injector lobe. I have the camshaft out of the 70 parts tractor and it looks much better. I'm considering having it ground by Roberts Carburetor repair. The fuel injection pump cam rollers are in bad shape and will be replaced....ouch....those JD prices hurt!

The governor looks okay but will need at least one new lead weight as the other one was found in 2 parts. Luckily, the fan shaft bevel gears look almost new...I'll be they were replaced. The drive gear is fairly worn though so I'm going to try and find a better used gear. I'm going to put new bearings and tachometer drive gears in the governor area.

Here is a 720 Diesel Row-Crop with a pony start. I just bought it from a fellow in Bennett, Colorado on eBay. Mom and Dad went out to get it as well as to take in some sight seeing in the Rockies. It's a real late 1958 model which is nice to have many of the improved features in the injection department.

The tractor last ran 4 years ago. The story goes that the father of the fellow that sold the tractor was using it to rake hay and it just quit. Well, apparently some gear teeth on the camshaft/ governor idler gear stripped off causing the camshaft to stop turning. It's been sitting outside since then, but there is very little damage ( I think) with the help of super low humidity in CO.

I've got the engine pretty much torn apart with the head & block at the machine shop. I'm 90% sure that it will need bored out .045 from the standard size. There was some rust and definitely ring grooves in both cylinders.

I found part of one of the governor lead weights so I'll need one of those. The crankshaft appears in fair shape with the rods checking in at .004-.005 with plasti-gauge (.007 is acceptable so I'm ok there). I'm going to replace the crankshaft oil seal and probably install oversized wrist pins.

The clutch looked decent when I removed it from the tractor. The drive disc looks new and was very tight on the crankshaft....so thank goodness that there's no problem there. The operating sleeve has some considerable wear on the drive pin and on the sleeve itself so I'll consider having the machine shop make it like new.

I drained a bunch of curdled oil out of the power steering unit....ugggghhhhh! I decided on only disassembling the power steering pump and installing new seals for now. If need by later I can always rebuild the power steering unit without worrying about anything behind the radiator.

I drained a fair amount of nice clean H2O out of the transmission and 1st reduction areas along with lots of nasty old gear oil so it will be interesting to see how the gears look. Hopefully there wasn't enough to ruin the PTO bearings in the belly of the beast!