The Lister Tractor Project
Page 5
After more than 5 and a 1/2 years of sitting, the spider webs and dust were recently removed from the Lister tractor project and assessments were made as to what the next step should be. First priority is to upgrade and repair the rear end in order to get a rolling chassis again. WAY back in 2003, the unprotected rear axle got into trouble and was bent, and with other projects and priorities pending at the time, the whole project became sidelined, collecting dust and occupying valuable floor space in the shop. In that period of time, I acquired a full size modern tractor for the property which now leaves this project a bit less needed for real work. With the recent fuel prices and the apparent waning interest in old equipment by the general public, the future of this tractor is a little uncertain. But, for now, the torch of fabrication will once again burn...
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First order of business is to replace the bent rear axle which means acquiring new (better) material and remachining a whole new shaft. This rear end has the unusual configuration in that a solid axle shaft extends from the left hub, through the differential, and almost out to the right hub. The right hub is actually attached to a length of heavy mechanical tubing which has bushings inside that ride on the solid shaft from the left side. One side of the differential has a gear pressed onto the middle of the long solid shaft to drive the left wheel, while the tube driving the right wheel has the other differential gear pressed onto it. It was the solid shaft that was bent a few years ago, so that has now been replaced. In order to pick up where the project was left several years ago, the rear end housing halves will undergo some modifications to strengthen and enclose the axles. This will require fabrication of two torque tubes containing seals and bushings, and modifying the housing to accept these tubes.
Some thick wall mechanical tubing is turned to size and the end I.D. turned to accept a bushing and seal at one end. Since the actual axles are different O.D.'s, the tube for the smaller axle also has to have a bushing carrier turned, pressed and welded into the tubing end. The rear end housings have to be machined to mate with the torque tubes, one tube pressed inside a housing half, the other tube pressed over the outside of the extension of the second housing half.
This shows the larger mechanical tubing axle with its associated torque tube. The torque tube will be pressed into the rear end housing. There are bronze bushings at both the outer end of the torque tube and also in the housing which carries the right side of the differential. A seal will be placed in the end of the torque tube to hold back the lubrication oil. The ground sleeves seen on the axle were added to provide a surface for the seal to ride on and provide the bearing surface which will run in the bronze bushings. The keyway had to be welded up to seal the oil in.
Once the torque tube is pressed into the housing, it is brazed in place.
Here, the three main components of the rear axle, the long solid left axle, the differential assembly, and the right side axle tube. You'll note that unlike most automotive differentials, this unit is driven by a 3-row chain.
Here, all the pieces except the input shaft are shown in mock up form. Taking into account the gear ratio between the input shaft and large gear, and the chain ratio from the small to large sprocket, the full reduction from the input shaft to the axles is a little over 31:1.
A final fitting of the drive train in the now modified case is done prior to assembling the case halves for a final fitting under the tractor frame.
With the rear end now fully modified and repaired, it is placed back under the tractor frame where additional horizontal struts are added to further strengthen the wheel bearings to the frame. This should relieve the rear end housing from any fore and aft lateral stress.
Vertical struts are also added to carry any weight changes while towing away from the rear end housing.
Started June 25, 2001 - Updated July 12, 2008
Some thick wall mechanical tubing is turned to size and the end I.D. turned to accept a bushing and seal at one end. Since the actual axles are different O.D.'s, the tube for the smaller axle also has to have a bushing carrier turned, pressed and welded into the tubing end. The rear end housings have to be machined to mate with the torque tubes, one tube pressed inside a housing half, the other tube pressed over the outside of the extension of the second housing half.
This shows the larger mechanical tubing axle with its associated torque tube. The torque tube will be pressed into the rear end housing. There are bronze bushings at both the outer end of the torque tube and also in the housing which carries the right side of the differential. A seal will be placed in the end of the torque tube to hold back the lubrication oil. The ground sleeves seen on the axle were added to provide a surface for the seal to ride on and provide the bearing surface which will run in the bronze bushings. The keyway had to be welded up to seal the oil in.
Once the torque tube is pressed into the housing, it is brazed in place.
Here, the three main components of the rear axle, the long solid left axle, the differential assembly, and the right side axle tube. You'll note that unlike most automotive differentials, this unit is driven by a 3-row chain.
Here, all the pieces except the input shaft are shown in mock up form. Taking into account the gear ratio between the input shaft and large gear, and the chain ratio from the small to large sprocket, the full reduction from the input shaft to the axles is a little over 31:1.
A final fitting of the drive train in the now modified case is done prior to assembling the case halves for a final fitting under the tractor frame.
With the rear end now fully modified and repaired, it is placed back under the tractor frame where additional horizontal struts are added to further strengthen the wheel bearings to the frame. This should relieve the rear end housing from any fore and aft lateral stress.
Vertical struts are also added to carry any weight changes while towing away from the rear end housing.