Hi all. I'm new to this so please bare with me. I have a 2012 hitachi zaxis 60usb-3f Thai I've been fighting with, going on 3 months now. Somehow over the winter water got into my hydraulic fluid and contaminated it. I was using it over the winter and blew a line. I didn't change the line for almost a week because of the weather and I belive that's where the water got in. After changing it I didn't use it again until spring. I started the machine and let it warm up when all of a sudden there was hydraulic fluid everywhere. I opened up the machine and found that the top of the swing joint was cracked all the way across and the deal was hanging out. I bought a new top and seal and replaced them. I started using the machine and it was working okay when I started hearing a whining sound on both travel motors. I started trouble shooting. I lifted one side and ran the track back and forward and heard a crunching sound and knew that wasn't good. I then tried the other side and it was doing the same but it immediately locked up. I took the final drive off that side and opened it up to find catastrophic damage to the pistons, so knowing that the other side sounded bad I figured it was the same and removed it as well and yes found the same damage. I replaced them both with Hitachi rebuilt final drives. After getting rid of all the old fluid in the system and changing at the filters and putting premium fluid back in, I started the machine. There were no leaks or noises so I slowly moved the machine around and everything was good. I got out of the machine to find that one of the drives had started leaking slowly so I moved the machine and then suddenly the left track locked up. I shut it down and took another look the side that was leaking works fine. I tried to move it the other day and the track is still locked but now the seal is slowly leaking on that side now too. Can anyone on here help me figure out what's wrong. Could the center swing joint be creating all these issues?
Welcome to HEF hh . Quoting you, “I opened up the machine and found that the top of the swing joint was cracked all the way across and the deal was hanging out.” . Are you referring to the swing motor as the “swing joint “ ?
If you're talking about the rotary manifold is there a chance you got some lines mixed up and have the two speed line hooked to case drain? Possibly pinched a seal during reassembly? Have you verified that travel motor case drain line runs back to the tank with minimal restriction/backpressure?
Never mind , 92U 3406 figured it out . You are referring to the rotary manifold aka the center joint. Sounds like the case drain from the 2 propel motors are being pressurized due to leaking seals in the rotary manifold. The case drain fitting is in the center of the rotary manifold top cover that you replaced , that cover being cracked I believe is the smoking gun.
I marked all of the lines with colored ties and took alot of pictures from different angles to make sure I didn't mix up any lines. So my thoughts were that because it froze up the contaminated fluid and cracked the top that it froze inside the rotary manifold and cracked or broke something else in it? I marked all of the lines with colored ties and took alot of pictures from different angles to make sure I didn't mix up any lines. So my thoughts were that because it froze up the contaminated fluid and cracked the top that it froze inside the rotary manifold and cracked or broke something else in it?
I didn’t think of frozen moisture that caused the cover to crack, makes sense tho. At the same time the rotary manifold seals could have been damaged. You sound quite confident that there are no hoses incorrectly connected. Verify the case drain line as 92U 3406 suggests above. If everything proves ok, sounds like a reseal is next step. That style of rotary manifold is straight forward to reseal.
Thanks