I sold the 580K. Failing to take my own advice, I sold it to a friend. It is the 1988 version with Extend a hoe. These have a bolt on end cap at the end of the dipper holding the bucket pin. It's held in place by six bolts with 1-5/16" heads threaded into a welded steel bottom end of the dipper. A few years ago, I replaced the bolts, coated them with red Loctite, and torqued them down. I used it at least 2 years with no loosening. Chris has had it several months, it has seen a lot of use. I saw it yesterday, bolts have started to loosen again. I feel guilty, leaving him an ongoing problem. Anybody got a solution? I've thought of helicoils, Maybe a bigger bolt size, but width of the square the female threads are in may not be big enough. Bolt heads are too close together now, but maybe an Allen (female hex cap screw). Another suggestion, since they are in rows of three, maybe a piece of key stock across three heads & welded. It'd have to be cut if the wear the thread, but maybe worth a try.
No suggestions yet. Are there any miracle Loctite products?
Are the threads ok and the bolts are just loosening? If so drill the bolt heads and use safety wire.
I torqued them years ago, without them stripping. I replaced the bolts then thinking some unknown level of wear on female threads, I'll take up half the wear with new male threads. I used Loctite & felt it fixed the problem My father was mechanic Army Air Corps, worked on bombers, wiring them would have been his approach. I am worried too much force is applied for wire to do its job. If you think, I'll try it.
I have owned and operated a bunch of Case backhoes. I bought the factory parts and service manual for my 580 SK. I always thought it interesting that the VERY first page was the Loctite product list. I am sure someone will be along soon with more experience with this than I, but I know Loctite makes some really stout stuff. The machine is long gone. The manual did not go with it. I would sell that manual to a feller that needed it...
I would use red Loctite and safety wire. I have owned several jags over the years. They used safety wire everywhere. I got pretty good at it. I had a Snap-On kit but for the occasional use you can use vise grips
This was a common problem with the first series. The first upgrade we did at the dealership was drill the holes out bigger for 7/8" bolts retap the threads and use red loctite on bigger bolts. This works for a while but eventually comes loose. The second upgrade from case was a weld on version. The cap that unbolted made access to the extendahoe cylinder easy but the caps always came loose. The weld on cap was steel rather than cast. You just remove the cap, pin the weld on cap in place and use the extendahoe cylinder to pull it tight. Weld the cap on and no more worries. The kit was part# d103585, check machinery trader someone may still have these.
I have, in the past, welded key stock along a couple of the flats on the hex bolt (not welded to the bolt head, just the flat next to it) in order to keep it from backing out (did this for high stress gear box mounting). This will not work if your heads are recessed or the threads are bad.
I've looked into availability of these. No results yet. The retapping to bigger size seems promising, but I don't believe there's room for ordinary bolt heads. I've considered Allen head cap screws.
Would it be feasible to cut the cap off and put bolts in the holes, with the threads out, then weld the hexes to the inside of the cap ? Maybe double up thin nuts on them for locking strength ?? No room ? Weld the nuts on.
No nuts. This is a milled flat surface at the lower end of the extendable dipper with six threaded holes. A ductile iron cap fits on to provide the pivot pin for the bucket. Ductile is not readily welded. GGGraham mentions a part offered by Case in an earlier day one could weld to the end of the dipper, it was steel, so welding was practical. My present 580 Super N has a similar part from the factory.