“GP” Doesn’t Have To Mean “Great Problem”

At age 17, I started out with tractors with a real early 1938 John Deere “G.” Unfortunately, I sold it in 1979 to pay for the college education I had just finished at the time. Since then, I’ve had all the two-cylinder lettered series, but always wanted an early “GP” and “GP” wide tread. I had only seen pictures of wide treads that were operational. When I started out playing with tractors, JD had purged all its parts books and dealer info on the “GP” line. Routinely I would go into a dealership and they said JD did not make such a model and would tell me the “GP” were general purpose “As” or “Bs.” How times have changed. The big problem with a restoration in my case is parts procurement. I am not a machinist, but I am a pretty good assembler.

Over the past 20 years, I’ve worked on single cylinder hit and miss engines and most of the JDs from 1936 to 1960. The various units I had brought home plugged up the barn, friends’ barns, the backyard, etc. There was so much stuff around that most of the time was spent moving one unit to get to the other unit. I found out you can only drive them one at a time and figured either I would need a stadium for a barn or thin out the herd. Over the past few years, I’ve decided to obtain and work on the early two cylinder units, trying to go 1938 and under. Through buying, fixing and then selling, I’ve traded down to early unstyled units, for the most part, of the “AR,” “BR,” “G,” “D” and “GP.”

“GP” tractors were not among JD’s best thought out products. They have a lot of odd parts, are designed sort of mule-backwards and are unique as the only flathead of the horizontal two cylinders. Quite a few “GP” standards were sold in the northeast and a number of “GPWT” models went to Maine in potato country. I knew of a “GPWT” locally that a fellow collector, Mr. Prentiss Jenks, had obtained in central Maine and he was “going to get it done some day.” I always kept an eye out for how it was progressing. Unfortunately, he passed away before he got the unit really worked on. Several months later, at our annual plow day, his widow mentioned that if anyone was interested in any of his units to call her. Well, the next day, I was on the doorstep and a deal was soon consummated. The only thing they had really done was purchase a famous Van Zante hood with stenciled decals, which was covered with a bed sheet and carefully stored behind the family TV set in the living room. It had been safely protected there for several years.

The restoration work I shoot for is to bring a unit up to like new condition. I find an old picture from published JD file photos of the same model working the field, blow it up on the copier and post it in the garage for periodic inspiration. I take apart all components, cover critical faces of the castings and sandblast, then power wash the individual castings to get off the sand debris, replace all the bearings, felts, bore the block and put in NOS pistons and parts, etc. All parts are primed, then painted with JD green (JD paint has improved over the past five years; what a difference the new stuff is!). Usually units I like to get are kindly referred to as “Hail Marys,” ones that most people wouldn’t repair, but would part out.

I have noticed that on “GPWT” tractors, the main case often cracks where the quills bolt onto the main case pulley side, from the quill to the transmission cover; this is because the quills on the “WT” are so long and stresses at the case. Additionally, the head had a number of cracks in it. I had heard about a method of repair called “stitching” years ago and decided to use this. The fellow who does this in our area is Frank Casey of Millbury, Massachusetts.

According to Frank, stitching is a method developed in the 1920s, patented and used a lot until the 1950s. In early 1960, he purchased the remaining inventory of the company and has been doing this work ever since. Often times in cleaning off by sandblasting large cast pieces or various cast iron pieces, I have seen this stitching work and figured it was a pattern fault but the cast parts were actually stitched at the plant or foundry if they had casting cracks.

What he does is to “V” out the area with a sharp pitch, about 1/8th inch wide, and every inch or so run a literal stitch crossways to tie it together. Next he fits the nickel alloy stitch (which looks like a piece of welding rod with small round pieces every 1/4th inch on the rod), the metal is peened into the “V” and relieves the stress and strengthens the member by the cross stitch. It sounds complicated but is quite simple. The repair looks like a giant stitch you used to get when you cut yourself. I felt at ease about the repair work when I saw a pile of 1920s Chris-Craft motor boat engine pieces from a restorer in New Jersey there for repair. Those boats are easily worth 10 Hi-Crop tractors a piece. Although costly, the repairs have worked excellent; no problems occurred like I’ve had in the past with welding cast iron. It cost $160 for the case, $200 for the head (nine cracks) and $40 for the box.

Parts chasing included many NOS parts and reproduction parts and many used parts, including a compete PTO/power lift assembly. Surprisingly, I went to the NY Expo for one of these and it was sitting next to a tree; the friend I went with to the show had to pick me up off the ground when I saw it—I was so surprised to find one. At the same show was a “GPWT” that had the metal members that form the arm and the push rod. These were measured up and reproduced to look similar to originals. I use Timken bearing like the originals and supplied locally; the unit needed the JD7544 pulley bearing (a roller bearing), an out of production Hyatt bearing which is now made by Rollway of Rochester, New York, bearing number WS212.

During assembly, valve guides, governor shaft, most felt seals and almost all gaskets were obtained from Kevin Stober and Greg Stephen. Kevin and Greg have specialized in “GP” parts and have made restoration a whole lot easier for these units. Both know a lot about the model.

Other parts were obtained to make it like new. It is costly, but I do them over a couple years so I get whacked a little bit at a time.

I built a drawbar platform and put it on, using old ad copy for an idea on how it ought to look.

The swinging drawbar and support were an item I had seen in the parts book, but had never actually observed one. The drawbar goes from rear final to rear final and is about five feet long. A supplier for our family drilling company in Pennsylvania made this and even made it out of the specified steel. I can see from the design that if it was pulled hard, the finals were torn apart by literally pulling the finals together. That is probably why few, if any, still exist. Maybe it ended many “GPWT” tractors.


The unit was completed in late 1997—two turns and it was running. For the first time on an engine rebuild, I used break in oil. The previous restorations I had put in 30 weight and broken them in. These units have been real tight, almost too tight actually. The 10 weight break in oil was run for 15 hours at light load and getting the unit up to about 180 to 200 degrees. I drained the oil out and replaced with 30 weight HD oil. The break in oil was turbid and you could see the very fine signs of metal wearing in. When you use this, you will have weeping from the crankshaft but it stops when you replace it with the heavier oil. What a difference using this makes. The unit has great compression but rolls over easily. I am now a believer in break in oil; the product used was JD break in oil available from our local dealer. If you’ve never tried this, I highly recommend it. Probably most of the senior repair guys already know this, but I wanted to pass this on. Additionally, I used the block sealant that pours out like rabbit droppings and is dark brown in color. It comes in a one-half pint bottle from NAPA. On a previous unit I had done, an “AR,” I had a weeping area on the head. At the same time, our business had a new Cummings KT 525 horsepower six cylinder unit delivered that has individual heads; the engine is a 1,150 cubic inch motor and has about a six inch bore. In talking to the factory rep about my weeping problem, he said they used this product on new engines to seal them at break in at the factory as it does not plug up the radiator and just plugs the weep from evaporation at the weep spot. He mentioned I should not confuse this with the radiator sealant (silver or gold stuff) that does plug up the radiator.

While doing the unit, my eye was on the next project (isn’t every one of us like this!). I put in an ad under wanted for a restorable early 1928 “GP” but I did not get any response until one evening about six months after the ad was published. A fellow in Minnesota called one night and had a rough one and he needed to move it fast; the price was fair and so I secured the same. It is number 200250, the 39th built; what a lucky find. That unit is now under repair, the transmission and engine are done and am now working of the finals. The second one goes a lot faster as you know which parts are which, plus with “GPs,” you can find a lot of parts units around. I think I have four carcasses now in the back hedgerow.

Regarding the completed “GPWT,” unfortunately the welded block repair done on the side of the block before I got the unit weeps a little from weld pin holes and heat cracking during welding and will have to be fixed. I wish it would have been stitched. I’m now at the third try with another type of metal based epoxy. After welding, stitching becomes much more difficult so hopefully the super goop will work. Purists will note the 36 inch spoked wheels on the rear are from an F-20 Farmall. I balked and passed on the quoted price of $2,000 for a restorable F&H correct pair last year. However, my seating position on the tractor is more comfortable on the steel seat as I have more padding in my wallet given the $100 cost of the F-20 wheels, even though they aren’t correct. However, it’s a decision I will probably regret if history repeats itself.

The real test for my projects is to field test them and this will be done at our annual plow day in North Haverhill, New Hampshire. Only then will I know if the work done was really up to factory specs. Previous years have seen me in the middle of a freshly plowed field with my toolbox for a field repair. Maybe not this time.

Submitted by,

Bart C. Cushing

Keene, New Hampshire