Hello all, I have a ts14g that only steers one way all of the sudden. All the hydraulic components have been rebuilt - pump, flow reversing valve, double relief valve, and steering valve. We have had the hydraulic pump rebuilt 3 times in the last 2 years. I'm at a complete loss as to what to check next. Terex has the service manual online for free but it doesnt have much for troubleshooting in it. Any ideas?
Well without a schematic or more information I would take a wag that the cylinder may have a problem. Possible piston loose on the rod or deteriorating piston packings for one direction. Reverse the connections at the cylinder or valve, whichever is easiest, then operate it and see what it does, this will either confirm a bad cylinder or you have to keep checking. Have you made any pressure checks at the cylinder if so what is it compared to spec.
We havent checked the pressure yet. Last time we had the pump off the hyd tank was full of long metal filings. Its strange that it was fine all day, then the next morning it wasnt working. Although this machine has been nothing but problems.
Any time you have found metal particles in a hydraulic system you have to get right on it. Cylinders are well known for producing heavy amounts of chips when the bushings / wear strips get worn out or damaged and the piston drags on the bore. You really need to check into a complete tear down and cleaning if you expect to cure the problem. Swarf (chips) will become lodged in any crack or crevice and break loose at a later time and damage other components.
Disassemble and inspect your steer cylinders. If in good shape, reseal. Like others said, more than likely you have a cylinder coming apart. Once you find the problem component, a thorough cleaning of the hydraulic system is necessary to remove contamination hiding in lines, cylinders and valves. This could mean three sessions of clean oil in the tank. New filter each time. Run the machine stationary at moderate throttle. Hold cylinders at full stroke to full system pressure for 20-30 seconds until the hydraulic tank is 160 degrees. Cycle cylinders (all of them) many times while heating to flush particles around. Drop oil, filter and repeat. When you have the oil tank filter cover off, place several magnets within reach on the tank floor. Clean each magnet every time the filter is replaced. Leave magnets in there once done. Flushing hydraulic systems on any piece of equipment after a failure is very important. Cat has specific procedures for their equipment. Cutting corners will short you in the end. Adding a drain valve to your hydraulic tank will make life much nicer. I added a hose barb to the valve so I can slide a hose on to minimize the mess. I have a pic somewhere I can't find at the moment. I used a -16 street 45 screwed into the tank. Then a -16 hex nipple. Then a -16 quarter turn valve. Lastly a -16 x -12 hose barb. I take the handle off when not draining the tank. A plastic cap over the end of the hose barb. If you need a replacement steer cylinder, a salvage one from a TS14C-D should be the same.
If the hyd. tank has suction screens would help keep larger particles from getting into the system.