Revenge of the Kwikee PRE-IMGR Series 40 Step

Question

This is the one that was deploying and retracting at random and we found the ground from the Magnetic Door Switch was flaky and finally failed. Worked OK for the next trip.
Started engine and Step did a lurching Retract/Extend operation. That was for a couple cycles. Now it acts like something is mechanically loose, like a stripped gear, damaged shaft, etc. NOT the external linkage.

I found that Manual #875 relates to this Step. Here's the nomenclature:
Step: "40 Series" S/N 39398 - Probably made in 2002
Motor: "High Torque" P/N 9551 - Replacement seems to be 909502000
Control: 909508000 - Does NOT have the L O N G mounting tab on the wiring side - Seems to be called "Pre-IMGR"

Pre-IMGR seems to mean that there is a Motor (with a worm drive in it like a power window motor) PLUS another gearbox that drives the bellcrank which operates the steps.

What's my troubleshooting on this? The Motor DOES run, but it sounds like it's bearing load, then unloading (slowing down and speeding up) as the Step moves and stops.

I think I can take some screws out of the round gear cover and see the Motor part of the gear train.

SAFETY NOTE: I've disconnected both the 4-way main connector and the 2-wire motor connector.

Put me in, Coach! Give me a play and I'll make it!

j-d · Answer

UPDATE: Motor is held by three "long" (about 1-1/2") #10x24 screws. Two screw blind into the Gearcase, but the Third... Nearest where the actual motor mounts to its part of the gear train... passes through the Gearcase, has been exposed to 15 years of corrosion, and is STUCK. Tapping on the area, heating it, spraying Blaster, so far no joy. Nuclear Option is to remove the two screws that DO come out, and grind the head off that third one. Enables me to work on the stuck screw with a 1" grabbing surface but the Motor out of the way. Being aluminum, all this is soaking up the heat from my propane torch.

j-d · Answer

SITREP TWO AND FINAL:Spraying Blaster, WD40, and trying the Melted Candle Wax trick, heating with a torch, tapping on the casting the third screw threads into...Still Broke It. Less than 1/4" sticking out where I could grab it with ViseGrips. I was able to finally remove it, took about two hours, but I was able to reassemble with the two original screws and one with same thread, even hex head size. Dismantled the Motor part of the Gear Train. Center of the plastic gear that the motor worm turns, was a mass of plastic chips. Cleaned it out and filled with parts I had on hand. Lubed and reassembled. Motor went back on easily, thanks to the way the motor gear shaft pilots into the upper part of the gear train. Clevis pin went in easily, and I noticed the steps move freely. Plugged in and OP tested. Smooth and quiet. Total time 4.0 hours, Expenditure $0.00, and for those tracking my adventures, Yes, I slid around on Cardboard.Case Closed. I ache.

fluffo2 · Answer

As an after battle review; long ago while I was in uncle sam's canoe club, we got three pairs of microscope slides (flat to within 0.0005") and positioned the pairs upward at a 45 degree angle. On the bottom of the first pair we applied one drop of generic penetrating oil, the second pair got a drop of "WD40" and the last pair got a drop of "Kroil". We let them sit overnight, and in the morning, the Kroil had wicked more the twice the height of the others. That made a believer out of me. Kroil is hard to find, but a 8oz can will last you a lifetime.. I'm not selling a product, not employed by them, but rather just sharing my experience. Over the last 20 years, it has saved my bacon plenty of times.

Bob

j-d · Answer

I've heard good things about Kroil before. Of course, here it is, right on Amazon...

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Revenge of the Kwikee PRE-IMGR Series 40 Step

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