Notes from Windward: #57

Return of the backhoe

The backhoe returns!
I'm very pleased to relate the story of the return of the backhoe to service. It's been a long convalesence, but it's running and starting to make a real difference. For those new to the Notes, I'll sketch a bit of background on the saga of the backhoe.

Some years ago, the sale of a real estate contract provided a modest windfall and the decision was made to invest the money into a backhoe. There are lots of things around here that are just to large and demanding to try to do with hand labor; life is afterall a timed event. After some searching around, we located a medium size John Deere hoe and worked out an agreeable price.

One advantage of this unit is that it has a gasoline engine instead of the more customary diesel. While diesel has a lot to recommend itself, it is a whole different game from gas engines. Since gas is what I understand and have tools for, I wanted a machine I was confident I could keep running. Used gear is cheaper than new, so long as you can do the refurbishing and maintenance yourself.

Hauling rocks from the garden
a ton at a time
The key thing about this unit was that the bearings were in good shape, the cylinders didn't leak and there weren't any major body repairs. The concept is that if the body and gears are in good shape, everything else can be rebuilt. That isn't to say that there wasn't a learning experience in store. There was.

Big, slow units like this don't have a rear axle like a car or truck. Instead they have something called a final drive. Two of these bolt onto the main body of the tractor and create the appearance of a rear axle. Within the final drive, a small gear eminating from the body of the tractor turns a large, 24" diameter bull gear. The axle is mounted into the hub of the bull gear, and that's how motive force is delivered to the wheels.

What I didn't know to look for, and probably wouldn't have understood if I'd seen it, was that the backhoe had been used improperly, and the end caps on both of the final drives were broken. The mechanics I've talked with explained to me that sometimes people use the bucket on the hoe to "slap" stumps out of the ground. The right way is to dig on each side of the stump, move the backhoe 90 degrees around the stump, and finish digging all the way around before trying to pull it out.

The shattered end of the final drive
In order to save time, some people will dig on each side of the stump, then slam it with the bucket to break it loose. This imparts great stress to the bearing hubs on the ends of the final drive. They're located inside where the tire bolts onto the final drive, so they're really hard to see. I'd never worked with a piece of equipment big enough to use final drives, so I didn't know to reach inside and check it out manually. Now I do.

We used the hoe the first winter we had it to move snow and do some light digging, but next spring when I was using it to clear some space, I hit an oak stump and was sickened by the sound of a large chrunch and the resultant leaning of the tractor. The impact on the stump had been transmitted to the final drive, and since the bearing cap wasn't in place, the axle shifted and broke through the cast-iron housing. With all the weight resting on the hub of the bull gear, the hub snapped right out of the gear.

We lifted the back of the hoe up, and chained one of our spare axels in place. That enabled us to tow the hoe back to the landing. It was only there that we learned the extent ot the damage. It was a sad day indeed. This was in an entirely different category than a blown water pump or a stuck float valve. In order to repair this, I was obviously going to have to learn things I didn't want to learn.

The broken bull gear
Just getting the old final drive off the frame proved to be a long term project. First of all, the backhoe consists of a front-loading bucket and the backhoe attachment, both of which had to be removed so we could get at the final drive. Then there was the matter of how to lift and support the final drive as it was slid out of place. It couldn't be lifted or lowered until it was first moved outward for some six inches in order to clear the power shaft coming out of the main body.

In time, I was able to track down a used military engine crane, rebuild it's hydraulic cylinder and rig it to do the job. It wasn't until we had it out that we could get a good enough look at the bull gear in order to be able to see that it wasn't repairable. The only realistic solution was to track down a replacement final drive.

Final drive remounted
attachments back in place
After considerable searching, and more than a bit of luck, I found one at a parts yard in Riverside, CA. Not only did they have it, they were willing to sell it for under a $1,000 dollars because the disk brake was defective. Since I had a good brake on our old unit, I jumped at the price. To sweeten the deal, they added in the two tires, which were almost new, for $100 each. We were now "over the hump."

The reassembly of the tractor, the frontloader assembly and the backhoe attachment went forward without much incidence. It was tricky work, the sort of thing that can crush a finger if you're not careful, but in due time, everything was safely bolted back into place. After sitting for so long, the engine didn't want to fire, but that was addressed by removing each of the spark plugs and squirting a mixture of half gas and half oil into each cylinder. When the piston rings sit for a long time, they lose their oil film which 1) makes them drag and 2) lessens their ability to compress. The gas/oil mixture cuts the friction between the rings and the cylinder wall, thereby allowing the engine to turn over faster, thereby increasing the compression.

The hoe lifts a cooling unit
onto the roof of Joyce's trailer
Once the final drive was back on and the attachments reassembled, there were a list of maintenance items to address. A couple of hydraulic hoses need replacing, rust had formed in the gas tank and all the joints needed greasing. After coping with the final drive, that sort of stuff was no sweat.

After a bit of driving it around to check things out, the backhoe was off to the garden to start it's first notable project - installing 180' of water lines in the new garden area.

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