Hello all first post here. Thanks in advance. Bought a 1990 Cat 211 LC last week pretty much sight unseen basically kind of knew the seller and it was a local deal. Problem is one track will not move in forward. Both tracks move fine in reverse. Lifting the bad side in the air you can see the track doesn't even try to move in forward direction. I don't know anything about tracked vehicles but it seems logical to me that the finals are OK but there must be a valving problem causing no flow in the forward direction.....wondering about that spool type valve in the pivot? No major leaks to speak of. All other hydraulics work fine.
EDIT....forgot to mention that the seller replaced a hydraulic cylinder to the bucket and it was low on hydraulic oil. We put 5 pails in.
When you try to move the problem track in the forward direction can you see anything to indicate that the hoses to the travel motor are getting hydraulic pressure..? Try moving the track in reverse and see what the hoses do, then compare that to what happens in the forward direction. Also see what the other side of the machine does - the one that works OK. You may have to remove some guards to do this.
Thanks for the reply Nige. I removed the cover/inspection plates to look at the drives. There are 4 hoses in there....two large diameter hoses...I'd say 3/4" at least and two smaller hoses....maybe 1/2" or 3/8" diameter. One at a time, I removed both of the small diameter hoses and I feathered the track control.....in both the forward and reverse direction. Fluid shot out of the hose approx 10-15 feet. Repeated the process for the good working track and had the same result....shot fluid approx 10-15 feet. I didn't touch the large diameter hoses. What do each of those hoses do anyway?
If it's like a 215 or a 225, and I think it is, the large hoses drive the track motors, and one small hose releases the brake, and the other is a case drain for the track motor. It's been a while, so I'm only 89.9997% sure of the case drain, I'm sure of the others. Do the big hoses jump when you try to walk that track forward?
Mitch is correct, the 2 large hoses are for forward and reverse (the oil flow goes in one and out of the other depending in which direction you want to travel), the smaller hoses are for the travel brake and the motor case drain. I suggest that you try to move the dodgy track in reverse first. What happens to the 2 large hoses..? One of them should visibly "jump" more than the other when the hydraulic pressure comes on it, especially if you have the track up against something solid and the machine can't physically move. Now try to move the track in the forward direction. The other large hose should do the same, but I suspect that you're going to tell us that it doesn't. Once you've done that compare what happens to the large hoses on the "good" side of the machine.
I did what you guys said. As suspected, I couldn't feel any pressure in the big hose on the bad track in forward. I was mistaken earlier when I said there was 4 hoses. There actually a fifth medium size hose also. A couple of unrelated questions: 1. What is that third for pedal for? 2. What is the "case drain" for that you guys mentioned above? She is currently loaded on my RGN and destined for the Cat house tomorrow AM.
In that case my money would be on a sticking/jammed spool in the main control valve that controls the oil flow for the bad track. Possibly it might be something in the pilot system. Don't understand your first question but regarding your second the answer is that all piston-type motors (or pumps for that matter) like the travel motor on your machine leak internally by design. The case drain is a line to take the oil leaking into the case of the motor back to the hydraulic tank. Your 5th small hose is most likely controls 2-speed travel.