1. Remove the small screw and grease sert that holds the plastic cover in place on the bottom of the Jack and pry the cover off.
2. In the Jack cavity you will see a beveled gear on the crank shaft that runs thru the Jack base. Clean some of grease from the beveled gear and you will see a pin that locks the gear to the shaft. One end of the pin is larger than the other end. With a hammer and punch hit on the smaller end and knock the pin about half out. Rotate the shaft to bring the large end of the pin to the top. Grab it with pliers and extract it. Be careful to not let the pin fall into the Jack cavity. Tap gently to avoid breaking the beveled gear.
3. Remove the crank shaft and beveled gear.
Parts needed (Ace Hardware): 1/2" (actually 12MM) X 12" eye bolt ($5.49) , 3/16 X 1" tension pin ($.30) , 3/8" all thread pipe nipple ($1.50), 2 pipe nuts ($.30), 2 large washers ($.80), drill with 1/2" chuck (prices vary).
4. Cut threaded end off of the eye bolt and dress with a file. Drill 3/16" hole in the eye bolt shaft about mid way. I chose the eye bolt to replace the crank shaft because it gives a way to rotate the shaft manually as well as connect to a drill. Also, the 1/2" eye bolt is actually 12MM, the same size as the orginal crank.
7. Put beveled gear in place. Push eye bolt through all threaded nipple and beveled gear. Line up 3/16" hole on axle with hole in beveled gear. Tap tension pin into place. I replaced the old pin with a new tension pin.
8. Add grease, replace cap, screw and grease sert.
Notes and Observations: Be very careful when knocking the pin out and back in of the beveled gear because if you break the gear, you will probably have to buy another Jack. The beveled gears are not precision gears and not designed to run at high speeds. I recommend using the slowest speed possible on your electric drill. Also, set the torque setting very low so as not to jam the upper and lower limits of the Jack. CAUTION: This inexpensive Jack was designed to be hand cranked and not raised and lowered at high speeds. It helps to mark red limit lines on the inner jack tube.
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Disclaimer: This is the method I used to attach an electric drill to my JUMP. I am in no way responsible or liable for anyone else's procedures or operations concerning the JUMP.
How I Motorized the Monkhouse JUMP
5. Enlarge the hole opposite the bushing hole big enough so that the 3/8" all thread nipple will fit into it.I used a small rotary grinder and round file to accomplish this.
6. Install 3/8" all thread nipple and tighten securely.
Copyright 2012 Walter and Jackie Monkhouse