Not sure if this is the correct place to put this but here it goes: I just acquired an older DH4B, Mitsubishi diesel, runs fantastic, backhoe works, but the trenching chain does not. If I pull the lever to move the chain forward or backwards, it will move JUST SLIGHTLY. Maybe one tooth, then stop. You can hear the hydraulic pump working, but nothing is happening. The linkage on the pump is free and you can see it move no problem. On top and on bottom of the pump looks to be two compression style clamps that turn a rod that passes all the way through the pump. They look like they can be adjusted, but I am afraid there is something more going on here. I have plenty of hydraulic fluid and the engine revs up just fine when more RPMs are needed. I should also note that the push blade in the front does not move at all. It is almost like there is no hydraulic pressure going to the valve body. I am wondering if I am missing a hydraulic line altogether. Any ideas would be great. *Update, I disconnected the hydraulic pressure line to the trencher hydraulic drive motor, when I did that I can turn the digging chain around a whole lot more. When I pulled the hose, water came out of the hydraulic motor, it is January up here in the north and I was wondering if the motor was full of ice. Gonna let it thaw out in the shop. The thing that I am wondering, is that I am seeing on the parts diagrams a 'selector valve' for the hydraulics. With the trencher not working AND the back fill blade not working, could there be a selector valve that I am missing? Is the hydraulic system split 50/50?*
These did have a selector valve for the trencher and backhoe
What's odd, is that I have three pumps. One for the backhoe, one for the steering and drive and one for the trencher and blade.
I also have a DH4.It had the same problem. It was left uncovered and water got into the trencher pump and gearbox. I had to take it off clean it out. Make sure you cover the pump if you leave the trencher outside.
I have a dh4 that has sat outside for 10 years motor is stuck Wondering if anyone has some pictures of what the levers do as all the stickers are gone it has trencher and blade and digger bucket at back Not sure if it's in gear or anything