1986 John Deere 650 Tractor - New Loader Mounting Pins

Here's a quick post about the pins I made for the loader. I had to drill out the old pins, as they were purt-near welded in place, it seemed. I found a two-foot chunk of 1-1/4" diameter round bar in the basement that I cut two 7-1/2" chunks from.

1940s Homemade Garden Tractor Gets an Engine and Clutch

I've been busy working on the John Deere 650 lately so I haven't posted much on this homemade tractor. As I'd mentioned previously, I crudely mounted a 1947 Onan BH twin cylinder engine. Since then I permanently attached the engine and made a belt tensioning clutch assembly and belt guard. This first photo is with a trial belt that is too long.

1986 John Deere 650 Tractor Engine Reassembly

Parts for my engine rebuild came in so it's now a simple matter of putting everything back together, right? First up was to press the new main bearings into the engine block. The front bearing presses directly into the block and the back bearing presses into a flanged casting that then bolts to the back of the block after the crankshaft is installed through the rear of the block. There is a funky center bearing on the crankshaft that is held in place by a large circular split casting. The crankshaft is installed into the block, then the center split casting is bolted to the block with one bolt. The rear bearing and seal flange is then bolted to the block. Here's a photo of the flange when I was removing the bearing:

1986 John Deere 650 Tractor Engine Disassembly

This is a Yanmar 2T80UJ two-cylinder diesel engine. Yanmar made the engine (and the tractor) to JD specifications, and I understand it's not identical to any Yanmar-branded engine. Fortunately there are still some aftermarket parts available for these things.

The first step in this engine's disassembly process was to get the engine moved from the motorcycle jack to the engine stand. I took the plastic fan off first, as it already had chunks missing and I didn't want to cause any further damage. I then took the engine stand's main bracket (the black thing that bolts to the engine) off the stand (the red thing) and bolted the bracket onto the back of the engine, then jacked the MC jack all the way up to get the engine as close to the height of the engine stand as possible. I put a blanket over the engine so I didn't get covered in oil when giving it a bear hug to move it, then manhandled the engine from the jack to the stand, fitting the bracket's rear stub pipe into the pipe of the stand. It's one heavy little engine, let me tell you. I'm guessing 200+ pounds. And you may be wondering why I didn't use the engine hoist? It's got the loader hanging from it.

1986 John Deere 650 Tractor Engine Removal

With the loader out of the way, I moved forward with taking out the engine. The first step in engine removal is to remove the front frame and axle. Of course it is. Ok, so the reason is because the engine block is an integral part of the tractor frame. The front frame bolts directly to the engine block, and the engine block is bolted to the clutch housing.

To get the frame disconnected, I first needed to remove the rear support for the loader (another "of course"). The steering arm drag link needed to come free of the front steering knuckle, and wiring for lights (of which there currently aren't any) also needed to be fished out, then seven bolts are removed. I supported the rear half of the tractor with a jack stand, then used a floor jack to balance the front end and roll it away.

1986 John Deere 650 Tractor Front Loader Removal - 10-hour Job

Yes, I caved and decided to remove the loader (like the service manual says to do, and frankly is required since the front axle and frame come off for engine removal) before going further on engine removal. Removing a loader isn't usually something worthy of writing a blog posting about. It's usually a fairly simple task of removing four pins, unhooking four hydraulic lines, and hoisting the loader off with an engine hoist or something similar. My tractor unfortunately is not simple. Nope. Removing this loader is about as far from simple as you can get without falling off the edge of the earth. The reason? Someone must have lost the two rear bottom pins and decided to make some. Problem was, the pins were made too large for the bushing bores and Big Bubba knocked them in with a 12-pound sledge hammer, I'm guessing. This first photo below is one of the pins. After about an hour of trying to beat one of them out with a 3lb sledge hammer, judicious application of heat from an acetylene torch, and an 18-inch pipe wrench with 2-foot pipe on the end (and getting absolutely nowhere), I decided something drastic was necessary.