ROOT CAUSE FOUND FOR MOST RECENT FAILURE TO CYCLE: For those of you who may have had steps binding and staying out or staying retracted...here is yet another thing that may be causing your symptom.
I had the steps fail to extend yesterday and no amount of tapping on the motor helped at all. If you have ever done any work on this step assembly you know how little room there is to get to the linkage when the steps are retracted. It took me about a half hour to pull the cotter pin and clevis from the crank arm to free up the steps so they could swing down and expose the motor and gearbox. You can see a bit of the layout of the parts I am describing in the manufacturer's information on page 7 -- the Tour Master uses the type "A" linkage arm layout:
http://support.powergearus.com/techdocs/82-ST0501.pdf
I first pulled the three bolts out of the motor assemble hoping to separate it from the gearbox -- but it was so jammed that I could not get it to come off even with the bolts completely out. Ended up pulling the four nuts off the gearbox mounting plate and getting the whole assembly out from under the coach so I could muscle it more...
Once the motor popped off the gearbox everything seemed free to move, so I looked more closely at the pinion gear that is driven by the flatted shaft on the motor to see how it was getting bound up. In the pinion gear there is a short shaft that locates/pilots the gear in the floor of the gear housing (the other side of the pinion gear is located/supported by the flatted motor assembly shaft and bearing.) All of this is clearly visible in the drawing on page 7 as noted above...
Note that in the mounted position, the 'floor' of the gear housing is up and the motor side is down, causing the pilot shaft to fall almost entirely out of engagement until it rests on the end of the flatted motor shaft
YES, it turns out that the loose pilot shaft is TOO SHORT to guarantee that it stays engaged in the mating bushing in the main gear housing. It is getting enough out of mesh with the larger gear that drives the crank arm that it binds up and stalls everything. I did not need to get a longer pilot shaft, although that would certainly have worked, because I found a simpler (local hardware store) solution. My observations and measurements indicated that I needed about a 1/4 inch of added spacer between the end of the motor flatted shaft and the pilot shaft to keep the pilot shaft up against gravity and well engaged in the bushing. The easy solution was to get a large set screw of 1/4 inch length to put down in the pinion gear before assembling the motor to the gear housing -- I used a 5/16 threaded setscrew, but even a small plastic spacer would have worked as no mechanical load is on this added spacer part. Now I am sure that the pinion gear is properly aligned with the larger gear and not riding up to be tooth on tooth and binding.
To make the job of disengaging the crank arm from the step frame easier if I ever had to take that clevis pin out with the steps retracted in the future -- I replaced the clevis/cotter pin combination with a wire loop self retaining style like you see here:
http://www.summitracing.com/parts/aa...FQqCfgodjKAAVA
Hope this is of some help to other members here -- I feel like this fix addresses the jamming I was getting from time to time and had been erroneously blaming on motor brush intermittent contact... Time will tell.
Chuck