Repair and Modifications to My QA 42-A Snowthrower
Several weeks ago when doing a small snow removal job with my trusty 1250 Cub equipped with a QA 42-A snowthrower, I heard a loud pop – never a good sound. Shutting down and examining the tractor and snowthrower didn’t reveal anything abnormal. Thereafter, while attempting to move a small mound of snow, I noticed the left side of the snowthrower moving toward the tractor! Inspection showed that the left side hitch plate had become disengaged from the tractor hitch bolt. Normally this could not happen unless the front quick-disconnect pin had come loose from the tractor. Fortunately the snow removal job was essentially done so the machine was put into the garage and the snowthrower removed.
After removal, the problem was obvious – the left-side quick disconnect hitch pin had broken off flush with the hitch plate, thereby allowing no lateral support on the left side. This is what I saw:
The pin, which is actually a round head clevis pin, is welded in place on the outside of the hitch plate. All that was left was a .5” diameter hole where the pin used to reside:
It appears that the reasoning behind using two individual pins in this location is that it makes for easier adjustability of the hitch plates to fit both narrow and wide frame tractors. As I intend to use this snowthrower only on my wide frame 1250, modifying these hitch plates to use a through shaft in this location (similar to the mower deck lift linkage) seemed a good idea in that more strength would be obtained with a through shaft instead of individual, cantilevered pins.
Both hitch plates were then removed from the assembly. Using a milling machine, the heads of the original clevis pins were milled away with an end mill. The remaining pin on the right side plate was hammered out. Here is the left side hitch plate showing the results…a .5” diameter hole remains:
Then a length of 304 stainless steel shaft of .5” O.D. was obtained and cut to 15” length, with .125” diameter cotter pin holes drilled .375” from each end:
While apart, I’ll share the most unobtrusive and easiest modification to the belt adjuster screw to keep it from backing off. Using 2 each wave washers of .535 ID X .875 OD stacked together along with a backup flat washer, these are placed over the adjuster screw on the inside of the hitch plate.
Apply some grease, then tighten the retaining nut until some rotational resistance is felt. Insert the cotter pin and you’ll never experience a loosening drive belt again. The wave washers are available through McMaster-Carr.
With all parts cleaned of dirt and old grease, assembly could then proceed. This is what it now looks like:
The through shaft should provide much improved strength and rigidity to the mounting system, thereby eliminating a source of failure that I experienced. I feel it’s a good modification to the QA 42-A and wanted to share it. Now let’s all hope we don’t have to use our snowthrowers again until next Fall.
Dave