how hot should the hydraulic tank get on a backhoe? after i run mine for an hour or so it get so hot you cannot touch it with your bare hand? is this normal?
Welome to HEF caseman1! That does sound pretty normal, I would not be too concerned. If you wanted to be really sure check the actual temp of it. If the oil cooler cores were blocked in any way it would usually affect the engine temperature as well.
any time oil gets above 230*f it starts looseing it ability to protect against wear. So keep this in mind
With the above said, it gets pretty hard to touch something with your bare hand and hold it there that is over 130 degrees F. Get a non contact IR temp gun if you really want accurate temps. They are made by Raytech and others, and run about $20 - $50.
Your main relief or one of your system relief valves are probally bleeding by. If you can get your hands on all the piping in the back and the valve under the seat you might be able to find 1 hose that is way hotter than the others. If it is a return line from front or rear valve it will be the main relief.
I'd suggest the IR gun route. They're super useful and not much of an investment. Just a general heads up, when checking if somethings hot the touchy-feely way use the back of your hand.
I second what JeremiahSr said. I just went through a similar problem on my Deere. I could start the machine cold, operate the hydraulics for 5 minutes, and there would be steam coming off the lines cause they got so hot. It ended up being "1" O-ring inside my load sense relief valve. It was blown out (Gone to, Never, never land). Fixed that, put the valve assembly back together, and it was good as new. Took me 1 week to track that little $0.10 sucker down since it was an internal leak , what a nightmare. Now I can dig for hours, and still am able to touch the hydraulic tank with my bare hand. Now, all that being said, I don't know your machine, and maybe thats how yours operates normally. Just wanted to share my experience. Good luck with your machine