Serial #: RKG01630 D5G LGP I was working the dozer today pushing some fire lanes in around my timber. I started smelling hydraulic fluid and hearing some noise from the pumps. I stopped the dozer, checked the oil level and found that the reservoir was empty. The machine was idling and would not move (parking brake on- low fluid?), so I shut it down where I was working at, the machine didn't run empty for more than a couple minutes- and that was at idle. All fluids were full when I started and I backtracked my path and it had only been leaking for about 200' of ground travel. Question 1: Should I be concerned with any pump damage? When I pulled the rear inspection cover off, the rear pan where the drive motors are was filled with fluid. I didn't have enough on hand to fill the reservoir back up, so I put some drain pans under it to catch as much fluid as possible and decided to leave it where it is at to drain overnight. My plan is to get some more fluid tomorrow to add to it so I can crank it up and try to see where it is leaking from. Question 2: Would I be better off filling it with cheap fluid and limping it back to my shop, or should I drop the rear belly plate and repair it where it sits? My main concern is damaging the drive system by running it low on fluid or using the incorrect fluid. Question 3: Any recommendations on cheap fluids and tips for diagnosing leaking lines? I'm thinking it is one of the drive lines since the blade was operating without issue and the only lines that were wet from leaking fluid are in the rear end of the dozer below the bottom of the hydraulic tank. My sight glass is also not functional- so depending on where the leak is I may pull the tank and repair the sight glass. I'm a decent mechanic, but I've never been one to ignore good advice so any help is appreciated!
Yes you should be concerned about pump damage with a hydrostat machine. I'd put some oil in it and try to see where it's leaking before moving it. If it's gushing out I wouldn't risk driving it very far. Is there any way to clean where the leak is coming from to make it easier to see where the leak is? I think you'd be OK with a cheaper oil than Cat but from a reputable supplier. If it's a drive hose you might be able to feel where it's damaged/ruptured but wear a glove so you don't cut your hands on the wire braid. I had a drive motor changed in my skid steer and whoever put the new filter on didn't tighten it enough. I did about half an hour of work. Idled it to check my work. Got back in and it moved about 10' and stopped. I saw oil so shut it off. I think it was good it was idling just before. Couldn't find the source of the leak and just happened to grab the filter and it turned easily in my hand. They also didn't tighten the drive chain and ground off the screws holding the heater on. I purposely used tight screws so they wouldn't vibrate loose. I guess they've never heard of an impact driver. They also charged me almost 3 times their estimate. Idiots I won't let touch anything after that.
I ended up picking up 10 gallons of the Mobil equivalent to the CAT spec oil, I figured there’s no reason to cheap out at this point. I drained out the fluid in the back side of the machine’s belly pan. Unfortunately a thunderstorm rolled up so I did not get to add new fluid and crank it up to check for leaks. Most of the hoses are new that I can see, so I’m suspecting it’s going to be one of the fun ones to get to. In terms of access, there is a small plate under the drive motors, but that’s about it besides the access plate near where the winch would mount. I was hoping someone would have some pointers on access, but I’ll try to figure out which hose is bad tomorrow. That’s a bad deal on the skiddy, I’ve gotten to where I don’t trust some of the dealer mechanics much less the smaller guys. If this is more than I can handle I can always call a service tech from the dealer. We are fortunate to have good dealer support. But I’d rather do it myself if I can. I’ll keep the thread updated in case it helps anyone in the future.
Hopefully it will be pretty obvious where the leak is coming from. Hope it's not too hard to get to.
I found the culprit. I think I can access it through the right side panel where the battery master switch is and where the access panel is under the floor mat. Interestingly enough, there’s some ductwork running under the floor that looks to be connected to a condenser of some sort. Did they put duct work and condensers in every machine as it was built to save time? Also, is there an access panel under the seat? It looks to be sitting right over that condenser setup. I’m thinking about replacing a couple more lines while I’m in there but the access for some of them is kinda tight. If I could remove the seat and condenser it would simply things a lot.