Skoffer Variation
We only use our third row seats once in a blue moon, but the left one failed about two weeks ago. Naturally, this is the first place I came for a solution. When I saw the $250 price for the part, I thought screw that! I figured I could replace the worm & worm gear instead of buying that assembly. Well, the worm & worm gear are pretty expensive themselves, and no guarantee I could even get them to work. I carefully removed the motor and gearbox from the assembly... How? Took a little time to do it carefully:
Remove the bolts marked with red arrows
Carefully pry out the plastic retainers. The whole plastic cover and door will come out as a unit. Seats don't need to come out.
Remove clip and pin. Chisel and/ or grind off four rivets and punch them out. Will not separate easily. Rivets completely fill holes and are TIGHT! The motor and gearbox did not easily separate from the acme screw shaft. Can't remember how I wrangled it out, but that's irrelevant. I was trying to save the gearbox so I could install a new worm & worm gear. Found out when I had it on the bench, that ain't gonna happen.
The gearbox is sealed completely. No way to get inside, and probably not worth the trouble anyway. When you're removing the bracket with the motor from the frame, just crush the gearbox and yank it out. Nothing worth saving. You can then spin the shaft out of the nut that runs the seat up and down. Take that to your bench and grind the spring loaded bearing off the end. That leaves a nice center to drill and tap it. I used a 1/4-28 tap, which requires a #3 or 7/32" drill. Suit yourself on the size.
As I said, I bailed on repairing the gearbox. I considered using a window motor and gearbox instead, but ultimately decided to use the "Skoffer" method. Added a few refinements. Again, suit yourself. The following is what I did.
Drilled and tapped the end of the shaft. At that point you could screw a bolt and jam nut into it, throw it back in the frame with four nuts and bolts, and call it a day. I didn't like it flopping around, so I added a 3/16" "U" bolt from a wire rope clip:
The holes have to be drilled while it's on the bench. Punch the locations carefully from the outside, and use a small drill for pilot holes. You'll be right up against an edge on both sides. Not easy, but doable if you plan the position well, and take your time. Also, you need to grind a little clearance for the bolt or shaft to protrude from the bracket.
I used a 1/4-28 threaded rod, about 2" long, and piece of 7/16" hex stock, which I drilled and tapped. You could buy a coupling nut instead:
I prefer the longer coupling nut, so the socket can't slip off. A bolt head isn't much to grab on. Skoffer used a socket to drive it with the speeder handle. Suit yourself. I wanted this unit to be able to be driven with good hand clearance and the cover flopped down:
When I knew it was all functioning correctly, I used Locktite 609 to permanently (it can be released with a torch) lock the nuts and 1/4-28 stud in place. Invested in a few tools from Harbor Freight:
Don't mind having a few extra sockets and extensions around
The whole thing fits like a glove, and doesn't rattle around. If the other side goes, I've got plenty of spare stock to duplicate it for the right side:
A couple details to help clarify:
Sorry, no pics of the process, since I didn't really know where I was going with it at the time. Just kind of fumbled around until it was functional.
Thanks to Skoffer for the original idea. There's probably 101 way to get the the same point. Whatever floats your boat!