Re: [A/S] Malfunctioning electric jack 1974 Excella

[Jim Dunmyer <jdunmyer@xxxxxxxxxxx>]

Tony,
 Your jack sounds like mine. Instead of limit switches to stop travel at
the ends of the stroke, it incorporates a slip clutch of sorts, what we
used to call a "chatter clutch" on corn pickers. It makes a clattering
sound when it's overloaded or at the end of travel.

Unfortunately, that isn't going to be easy to repair, from what I've
seen of mine. I took the unit all apart to lube it, wanting to get at
the jack screw, and never did figure out exactly how that part is put
together. I just dumped a bunch of 90 weight gear oil down the tube and
ran it up and down a few times. Naturally, it dripped for several days
afterwards.

The clutch is in the piece that I couldn't get apart; I could see it,
but not disassemble it. It's entirely possible that yours is different
and/or you can decipher the puzzle, but the problem is probably either a
weak spring or (more likely) worn parts in the chatter clutch. I THINK
it consists of 2 "races" with indentations, several hardened balls, and
a stiff spring to mash it all together. It'll drive the jack screw until
overloaded, upon which the balls will ride up out of the indentations,
compressing the spring, stopping the travel and causing the loud
clicking that you hear.

I'm always very careful to not let the clutch chatter unnecessarily,
usually stopping a bit shy of all the way "up". Every time that clutch
slips, it's wearing; yours may simply be worn out. You may be able to
get replacement parts (and instructions!) from the manufacturer, or it
might be easier to simply replace the thing. Camping World carries
electric jacks for under $250.00, IIRC.; I think the bolt pattern is
universal.

                                       <<Jim>>