Farm Equipment Repair: How I repaired my old Simplicity Rototiller
I've mentioned several times on our web pages that I use a rear mounted tiller on the Simplicity 7116 for preparing planting beds. A picture of it in action is on our Planting Raspberries page.
This old tiller was on the tractor when I bought it from a guy in Ohio through eBay. I have used it for several years but had to modify it some to help it combat our rocky soil. The sheet metal guards over the tines were always shaking loose and falling off. The threads in the mounting bolt holes had reamed out completely on one side so I just tack welded the guard in place.
I also mounted a piece of 2" square metal tubing (the same heavy walled stuff I used for the legs of my Rock Picker ) across the bottom of the guards to stiffen them. On each side of the drive and tine shafts, there are bearing blocks bolted onto the outside of the case. The mounting bolt holes on one side of the tine shaft had also reamed out and would not stay tight. This allowed the tine shaft bearing on that side to loosen and the tine would hit the guards. When I heard that noise,I knew it was time to go back to the shop and retighten the bolts. I tried everything I could think of to keep the bolts tight, but nothing worked for long.
This old tiller was always very noisy but kept on tilling so I didn't worry about it. Just like any other problem in life, if you ignore it long enough it will force you to deal with it. Last spring (April 08) I was tilling a new garden bed when I heard a real nasty sound from the main casing of the tiller. The noise suddenly went away and the tiller quit. The drive pulley was still turning but the tines were not. I didn't have a clue how these things worked inside the case but when you use old equipment like this, you really have little choice but learn to repair it yourself or trash it and try to find another old one somewhere.
I visited the Simple Tractors web site to see if there was any help there. I found some diagrams for Simplicity tillers which showed a system of drive chains on sprocket gears inside the case. Not knowing if I could repair it, but having nothing to lose, I tore into it. I found that my tiller has 3 roller chains instead of 2 like the diagrams I had found. The chains and the sprockets had worn enough over the years that the slop in the chains had allowed one of them to come off it's sprocket.
This picture shows the inside of the case after the chains were removed and the old grease was cleaned out. The small shaft at the top is the drive shaft and the large shaft at the bottom is where the tines mount. I don't know how new tillers are built, but this old thing is pretty impressive. I'm not at all surprised it lasted as long as it did.
I knew I would never find replacement sprockets, but maybe I could fix the chains. I thought I could possibly shorten each chain by one link and remove the slop. I have never dealt with roller chain before so I 'd a little learning curve. It turned out that 1 whole link was too much to remove but there are offset links available which allow you to shorten a roller chain by 1/2 link. After learning how to measure the chain to size them, the smaller chains measure 1/2 inch between pins which corresponds to 4/8th of an inch so is designated as a #40 chain. The larger chain measures 5/8 inch so it is a #50 chain.
While trying to find the offset links I discovered that
Northern Tools
carries these chains as go-cart parts. The chains
come in ten foot lengths and include a master link.
The #40 chains were about $10.00 each and
the #50 was about $20.00. I wasn't sure that the chains from
Northern were the right ones and if they were, would new
chains remove enough of the slop. If it worked ,
for $40.00 I could replace the chains and forget about the offset
links in the old chains.
Here are the roller chains I purchased. There are listed in the Northern catalogue as including a master link. As my luck would have it, someone had removed the master link from every #50 chain the local store had in stock and they had marked out the text on the boxes mentioning the master link. I, of course, didn't notice and had to return it.
So if you need one these chains, check the box! I had to order a # 50 chain from the catalogue. Also please note that 1 ten foot section of #40 chain is more than enough to replace the two smaller chains. You will just need one extra master link which Northern usually carries in their stores.
As you have probably guessed, the chains worked great! This picture shows them installed on the sprockets. The little bit of slop you see in the top chain is because the drive shaft is leaning but will straighten up when the other half of the case and the other bearing block are installed.
Here the chains and sprockets have been completely covered with grease; the assemble with the mounting bolts for the drive shaft bearing block has been slip over the drive shaft; the top plate containing the bolt holes for the tine shaft bearing block has been placed over the shaft. There is a matching plate which is visible in the picture above.
These plates are separated by the spacers also visible above. Bolts go through the casings, plates and spacers. One of these bolts also holds the bottom hitch frame to the tiller. The 3 smaller holes around the shaft are the ones mentioned above where the tine shaft bearing block bolts. The threads in these holes were reamed out so I drilled and tapped them for 7/16" bolts instead of the original 5/16" bolts. I also messed up the gasket when I took the case apart so I used a heavy bead of Permatex.
Here is the case back together with the bearing blocks and lock collars in place. When the hitch frames, tines and tine guards are installed, it is ready to go again. It's amazing how much quieter the tiller runs with new chains. Maybe it will last another 20 years!