We could use a general write up on slow tracks. It's a common problem and people frequently have questions about what to do. I just asked one myself. Just wondering if some of the guru's here could write up a "how to" troubleshoot post for these problems. Not sure how it would be posted but it would be great if it could be made a "read only" Sticky on the Excavator forum. Read only so it doesn't get cluttered with chat. Don't know how it could be written or how to let multiple guy's write it but I bet alot of members would appreciate it. Just a thought. Rob
There are general things to check but each brand works a little different and even each model break has changes. Komatsu Dash 3 and 5 worked the same but Dash 6 and 7 are completely different. PC120 and 150 worked one way while PC200s on up worked differently. I'm sure the Cat A, B, C and D models have some differences also. Some machines have straight travel valves that allow the machine to walk straight when another function is used. Others use a merge valve to joint two pumps together when walking and split off the oil when another function is used. Most excavators though have the basics. One or two pumps, two separate main control valve blocks, a stack valve or one big mono block control valve. Oil then goes to a swivel or rotary coupler down to the motors. The motors usually have two main hoses, a case drain hose to vent pressure off the shaft seal and two speed control hose. All the modern excavators I've worked on had internal travel brakes along with some sort of counter balance valve. There are usual problems that go with each component. Working from the cheapest to the most expensive in my experience usually goes like this. Check for dirt under the pedals and make sure they are getting full stroke. Check hydraulic return filters for foreign material, especially brass and what will looks like cylinder packing. Check pressures on both circuits in both directions at the pump with gauges. Check case drain flows in each motor. Mark one pad on each track, pick up one side by pushing down the boom, spin the track at full throttle. After the track pad makes a full revolution, time how long it takes to run two or three more. Do the same on the other side and compare readings. If they are about the same, it's time to pull the swivel apart and check the seals. Since your there you might as well replace the seals so you know for sure that isn't the problem. Also if the track cycle times are about the same, then your pumps are probably OK at least at low pressure. After all this you are probably best calling the dealer and paying the money to find out the secrets about these problems that they know of. Things can be electrical, electronic, could be cut out valves on the pumps, load sensing valves, straight travel valves, leakage in the main control valves and so on and so forth. Good Luck!