hi all. I have 2 cylinders to reseal in my ex60-3. I was just wondering has anyone tried rigging up something with a mechanical torque multiplier tool to remove the large piston nut on the end of the rod, as I know they are very tight to remove. Thanks
You'd have to have a substantial bench to mount it on, or a substantial concrete slab with the appropriate attachment points. Look up hydraulic cylinder bench for how the pros or some do it yourselfers do them. The usual way to do them on your own involves a guy jumping on the end of a very long beam attached to a plate wrench. The rod being attached to the machine, or a dozer drawbar, piston end supported with wood block. Another excavator works if the length of the beam x weight of the guy isn't enough.
An EX60 isn't that big. I think a 3/4 or 1" drive socket and snipe should loosen it or just have a shop loosen and tighten it.
If you decide to do it yourself and have no torque toolting to reliably tighten it, centre punch a mark on the rod and one on the nut before removing. that way you can tighten it to the same place as it was before it was removed with no other need for torquing.
Some people even suggest counting how many turns it takes to remove.
The best mechanical torque multiplier for this type of disassembly is a 20# sledge on a slugging wrench. Even an 8# is better than a long bar or a torque multiplier. As suggested, the wrench can be burned out of plate if not on hand.
the only problem with that, is i'm not as powerful or as ambitious with a 20lb as i used to be
Nige, wouldn't it be better if he put the punch mark on the barrel ?
I walked into a shop in New Hampshire, met a one man crew who speciaized in rebuilding hydraulic cylinders. He was proud of his operation, and gave me a tour. His home built equipment involved hand built wrenches none longer than 2'. The cylinders were laid out on a very heavy duty table, fastened down securely. A hydraulic cylinder rode above on a beam trolley with swivel. The rod end had a cup to accept the end of the wrench. It was only good for 1/6 of a turn each set up.
Just a couple of thoughts, I haven't looked what a 60 size cylinder nut is torqued to but on a bit larger size they're torqued to 5000 ft. lb. Even at 3000 ft. lb. using a torque multiplier that's a lot of wind up torque waiting to spring loose. So make sure you have both the rod and the multiplier securely fastened down. Also, most of the older Hitachi's I've seen do not use a standard 6 point nut on their rods, so a standard socket or hammer wrench will not work. And, believe it or not, it doesn't take that much to put a slight bend in the rod from doing this the wrong way.
Let me try to explain it. If you are not using torque tooling the next best (and TBH most people's preferred) way is a home-built slugging wrench and a 20lb hammer as Terex Herder mentioned above. So the idea is to put the nut back in exactly the same position relative to the cylinder rod that it was before it was removed. None of the hard parts have changed, you're only changing seals. The illustration below is a typical cylinder with the piston retained to the rod with a nyloc nut. So you centre punch two marks, one on the end of the rod close to the outside (the arrow pointing up) and the second on the outside of the nut (arrow pointing left). When it comes to reinstallation, all it needs is to flog up the nut until the two punch marks line up again - simples. Believe me it's impossible to be a whole turn off doing it this way, the last 90 degrees or so you'll be beating the Bejasus out of the flogging wrench.
I agree 100%. Torque Multipliers frighten the ***k out of me. Using a flogging wrench with the end of the rod well-supported is probably the best way unless one has access to a proper cylinder bench equipped with a hydraulic torque tool.
I think Tinkerer may have been thinking of the gland nut.
Left the cylinders installed on the dozer and used a pipe wrench and backhoe to break loose and retighten
That's the gland nut. OP was asking about the piston rod nut. There's some videos of guys using a pipe wrench on the rod nuts and it just chews them up.
I think you may be right. I was reading what the OP wanted to do which was tighten the piston retaining nut.
OK, but do remember the posting (I think saving 955 from paper clips) placed the rod end on the rear of the 955 with pin thru hitch, then used backhoe to break loose. Another guy made a wrench with cutting torch and used same way
There's a few ways to do it. Tom V's hyd. torque wrench was one of the easiest but also priciest for one or 2 cylinders. If you could rent a hyd. torque wrench would be ideal.
I was !!
So I happened to stop by a hydraulic shop today and they were repacking EX120-2 boom cylinders and the nuts on those were a standard 6 pt. hex nut. I was a bit surprised.
Why so..? They are relatively large nuts but 6 flats is all you need to get hold of however big the nut is, especially on a cylinder bench. 994 Tilt cylinders the nuts were 4-1/2" 12TPI thread. As well as the nut the piston was also screwed on to the rod. First the piston was tightened to 600 ft lb using a peg wrench attachment, then the nut was run up to 13,000.
The one's I've seen in the past were not a standard 6 point, all flats were not the same measurement.
Fair point. All I can comment on is Cat & Hitachi and all of the nuts I've ever come across were standard (albeit f'kin big) hex nuts, usually of the nyloc variety.
We had good success with a big pipe wrench ,a long snipe and another machine until the pipe wrench broke.I think the other end of that thing is still in orbit. Do as Nige said and mark the nut with a centre punch and check the nut for a set screw.Hitachi used an allen screw with a little chrome ball to keep the nut from coming loose.
Whenever anyone mentions the subject of using torque multiplers I always hark back to this case........ https://www.dmp.wa.gov.au/Documents/Safety/MSH_SIR_133.pdf
NONE of us are!!
God Grief! how sad and avoidable, Nige.
That's only one that I remember well, because it happened on a BHP property and BHP worldwide immediately stopped the use of TM's on all their job sites, be that for their own personnel or contractors. A lot of scrambling went on really quick to get hold of hydraulic or air-operated torque tooling as a replacement. It was also one of the final nails in the coffin that convinced us as a dealer to stop assembling machines on customers job sites and instead do it at our own facility. The completely assembled machine(s) were either thrown on a lowboy and delivered to site, or roaded there under their own steam. See posts 848 & 850, or 861 on the following page. HeavyEquipmentForums
Have watched the ones I have used wind up Tons of stored energy, much respect given at all times.
The things we do when try to save time, it only takes a second to kill somebody.The problem with most young apprentices is that they think they are bullet proof!
Similarities with the young and their imagined invulnerability to coronavirus spring to mind .......