All 4 of my jacks have gotten stiffer through the years (much like my own joints) but one in particular now refuses to retract the last 6" or so. While it runs fairly smooth through most of its cycle, the last few inches of retraction deliver an unsettling grinding sound.
The grinding is evidenced by the galling of the rear washer shown in this pic:
Looking at how this infernal thing works, it's clear this washer, which is only in play during retraction, must have an unusual amount of strain on it (I know, rocket science right?). With the jack on my bench and some slop in the large jack screw, I should be able to flex the jack up and down slightly but it won't budge. Something is binding but the end bushings are good. (is this getting exciting yet?)
So I removed the jack screw:
At this point the jack should just collapse but it's so stiff it takes a 3lb mallet to make it move. I took out the top bolts and ultimately found that one of the bolts at the bottom has been torqued way too tight and is causing the whole jack to bind. This results in the galling which further restricts movement.
The bolt on the right was my nemesis:
After loosening it the jack worked freely. I replaced the galled washer and applied a thin layer of grease on the bolts after removing any rust with a wire brush on my grinder.
Ready to go back together: (old galled washer on right)
I tightened the pivot bolts by hand and stopped just as they became snug. Then I re-installed the jack screw with a new hardened washer and lightly lubricated the parts that move against each other. A simple spring loaded pin like the one that holds a draw bar pin in a hitch is all that keeps it together.
After installing the remaining upper bolts and tightening in the same manner as the lowers, the jack worked perfectly and I re-installed it on the TT.
I went around and checked the other jacks and found that many of their pivot bolts were tight enough that they caused binding and prevented the jacks from completely nesting. I loosened most of them 1/8 to 1/4 at which point they were immediately able to move freely enough to fully retract. I think this nesting part is very important because if they don't nest then road grit and grime gets to the threaded parts.
The other problem I found was with a jack that got slightly bent once. You can see the evidence of this in the scarring:
I used a clamp to gently bend the sides back together so that source of binding was eliminated. I also adjusted the pivot bolts.
All of my jacks fully nest now and lower with much less effort. They work better than new! I suspect the factory is jamming these things together with an impact wrench and just over doing it a bit.
Hope you enjoyed this as much as I enjoyed not buying 4 new jacks!
Cheers,
Scotty
Scott, Grace and Wesly
2003 Dodge 3500 4x4, 6 speed Cummins (lightly bombed),
2004 Forest River 25RKS many, many mods.
H0NDA eu2000i
Well I hope not. I don't really think so because when I pull them all the way up, they kinda bind as they nest. I have to give them a little extra torque to pop them free. That should be enough to hold them.
I had similar jacks on another TT that would migrate down unless I cinched them in the up position so these are probably just working the way their supposed to now.
Good job Scotty and nice find… I don’t think once they are snug in the up position they will give you a problem… I know you said you lightly lubed everything, but you may have to clean the lube off the friction washers (only maybe)… sometimes when they work freely they will back off very slowly after you stabilize the trailer…
I only say this because I have had it happen with 1 jack on 2 different trailers before after I lubed them…
Love my mass produced, entry level, built by Lazy American Workers, Hornet
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