I have the above titled dozer and it just suddenly won't move. The engine runs fine, the blade goes in all directions, but the nothing happens with the traveling joystick. It was a bit low on hydraulic fluid which I topped off, so the only thing that makes any sense to me is that it might need to be bled, but I don't know how to do that. Anyone have any ideas or suggestions?
Fuses? Safety switch somewhere? Probably a bad relay. Solenoid valve not working? Are you getting any lights or buzzers for charge pressure? Since the blade pump is working that means at least one pump stack is turning, the pilot pump is piggybacked on the other hydrostat I think. I'd check pilot pressure first, then electrics. Should not need to be bled, unless you were hearing horrible growly noises when it decided to stop working.
I checked the fuses. All ok. It wasn't making the noises you referred to, it was down about a gallon or so of hydro fluid. It did have a light on for that. It went out when I put juice in. So, I guess we can eliminate that. As for other switches, relays or solenoids, that's probably the issue, I just don't know where to look or how to eliminate. Behaviorally, it sat for about a couple weeks, I came out and fired it up and it was just a no-go. It's kind of like the parking brake is on, however, even with that, I think it tries to nudge ever so slightly before it totally locks up. The brake is definitely off and as I read in another post about that switch possibly being bad, it appears mine is a hydraulic line valve that is opened/closed via the parking brake lever. I don't think that's the problem. I appreciate the information...
LOL, you are the third guy posting here in a week with a hydrostatic dozer that's locked up. I'm # 2. Yes, I'm number two. Number two of course is a polite way to reference something...well,you know. I have deduced that my problem on a D5G is probably electrical and will be getting some parts tomorrow. On the other hand, the lead CAT mechanic said something about a blown pump motor will cause a solenoid to cause the tracks to lock up. Sumpin' like that. Good luck.
Well, great news. I finally got to the bottom of this a couple of months ago. I hadn't gotten around to posting the solution here, but I am now. I hope this helps someone. I couldn't find a mechanic to work on the dozer, so I got in touch with a maintenance mechanic at a golf course who keeps all their mowing, etc equipment running. This guy is unreal. Anyway, he came out and helped me go through the dozer. We found several rat-damaged wires that we repaired. This didn't help. He took my shop manual home and studied it. When I got back in touch with him, he gave me a couple of things to check. It turns out that under the floor plate, there is a hydraulic ball valve he wanted me to check. It was indeed closed and as soon as I opened it, the dozer operated normally and away I went. Now the only question that remains is how did the valve close? I only have 2 working theories on this. 1 is that my hydraulic fluid got a gallon or two low and maybe it closed as a "fail-safe" of some sort to make me put in fluid? The only other possibility I see is that the rat could have possibly brushed past the valve on one of his trips through the compartment and closed it. It doesn't take much pressure to move it. Anyway, it doesn't matter what caused it. If anyone experiences this type of problem, make sure and check for this type of valve....