So I've been working on the old 580c trying to get it working properly. I starting tackling some of the more serious cylinder leaks. The first one I did was the dipper cylinder. It took almost 4 grueling hours (including a trip to Tractor Supply) but I got it done. The bolt that holds the piston on was crazy tight and had red theadlock on it. It took a 3/4 breaker bar with a 6 foot cheater, and lots of heat to get it off. When I reinstall the bolt, I mounted the piston rod back on the hoe, put some blue threadlock on and wrenched it on there with all my body weight using my 3/4 breaker bar. After resealing 2 cylinders I learned that the bolt should have been tightened to 1200ft. Lb!! Is that right? I can't imagine I tightened it even half of hat much. Should I be concerned? This thing is not going to get used much and I really don't want to take that cylinder apart again. Is 1200ft lb really necessary?
I personally wouldn't take it back apart to retorque it. BUT I am just a DIYER so my opinion is worth every penny you paid for it. I have used blue lock tight and a 1" impact on a couple of mine. Before I bought that I would use the same 3/4" pull handle with the same pipe extension I used to remove it. Never measured the torque on any of them.
I have run into the same problem you are having. Had to bolt and re-enforce my work bench, then broke my vise, then broke the harbor freight 3/4 drive breaker bar. I have gotten them all loose except two. Those I had to take to a shop were they had a 1 inch impact and it took them right off. Like you, I tightened them back up as good as I could with a cheater bar, and haven't had any problems so far. I redid all the cylinders on the rear part of the hoe. The harder ones are the swing cylinders. They have a cushion pin that sticks out of the piston and prevents you from using a socket. I use a large pipe wrench on the nut with a very long cheater bar on those.
Thanks for the reply. I actually did one of the swing cylinders also. I was able to do it with a regular socket. I did have to apply some pressure to compress the spring on the pin. I'm just worried that I didn't tighten them enough. Didn't use the cheater bar to tighten it. Just the 3/4 breaker bar..
I’m sure it’s fine. With thread locker on there you made up for it.
I've done a doz. or so with no ill results after many hrs. The only one I made sure to really torch was the boom piston as I had one come down with a bang when the wrong bolt some one had used broke.
Before installing the bolt holding the piston, I like to heat it up with a Mapp gas torch, till it’s to hot to grab and I use red thread locker and I use my 1/2” impact at the highest psi on my compressor. I also put in a bit of oil in the impact because I will get a few more pounds of torque, with the oil. Because heat will expand the threads and get it on that extra little bit.
With the intended use (cycles), I would not take it back apart. If it were to be cycled at a higher rate, such as professional use, I would consider it. My advice....move on and forget about it .
I calculate my body weight at the correct distance on cheater bar. I wouldn't worry about it. Did you have 1pc piston or 2pc piston?
It's an earlier model (1975?) with the 2 piece pistons.