Since working on Bolens equipment in my Dad’s dealership as early as 1964, I have had a growing admiration for the design engineering of the equipment. In addition to being on the leading edge of innovation, the execution of the designs was first rate. As an example, you should look at the rear half (engine, transmission, etc) of an Estate Keeper. There is a lot of stuff packaged in a really constrained space. And it all works reliably, is serviceable, and has few deficiencies.
We sold only a few large frame tractors out of my Dad’s dealership, so I don’t have a lot of experience with them. When I found a tired 1250 for a reasonable price, I decided to restore it. In the process, I found a rare design error that had resulted in a major failure.
The steering of my tired 1250 was very loose. There was play in the normal places: spindle pivot bushings, steering gears, tie rod ends, axle pivot, etc. But only after disassembling the tractor did I learn that the majority of the play was coming from an unexpected failure of the axle support casting 1718572. This support basically connects the main structural channels of the frame to the front axle, as well as providing the structure for the PTO drive. The casting is a vertical box section and had split down the left hand rear corner. In looking over the failure, the inside corner of the casting was made at a sharp right angle, without any appreciable radius, ribs, or webs between the left and rear sections. The right angle corner served as a stress concentration point and resulted in the failure. As a result, the front axle wasn’t completely connected to the tractor frame, resulting in really sloppy steering and excessive front axle movement.
I contemplated different ways to repair the casting, but found a similar casting from an HT-20 (1722832) for sale on ebay. The pictures on ebay were detailed enough to see that this casting had added webs and a rib in the area where the 1250 casting had failed. I’m sure the design change was due to numerous failures similar to the one in my 1250. I made a study of the parts around the casting, comparing the 1250 parts catalog to the HT-20. There weren’t many differences, so I took a chance and bought the HT-20 casting. It turned out to be a drop-in replacement I will have to extend the hood hinge mounts on the front of the casting). Engineering problem fixed. My faith in Bolens’ engineering restored.