Hi All, when I activate my right track drive motor in the forward direction, nothing happens, no load on the engine, no drive, etc. When I activate the same motor in reverse, there is a delay, than a "thunk" as the motor starts driving in reverse. I had my son operate the foot pedal, it's not getting stuck, has a full range of motion, can the control valves go bad? Any ideas why it would work in reverse, not forward? Thanks all.
Well the thunk is more than likely axle block bearings, loose spline on the axle/sprocket, the mounting link bolt that secures the final is loose at the point it's mounted to the frame. We need to know the series 35 A/ 35B/ 35D, the a series had a stacked valve section valve and the b and d had a one piece valve. You could have a bad relief valve, or a swivel o-ring blown causing a no pressure issue. If it's a b or d series put you hand on the spool for that track, above the spool is the relief valve, then on the other side at the end cap is the other relief valve for that track. Unscrew the spool end relief and switch it with the rear end cap side and see if your track will move forward and reverse has now quit. Make sure you screw the whole relief out and not parts of it. If like said the track now pulls, then you have to disassemble it and check the seat/spring and internal parts (may have some trash in it). You should measure the threaded adjustment screw to be able to get the setting pressure close when putting it back together. I can give you the psi setting if you give me the series also. More if needed.
Thanks for the reply Sheepfoot. It's a 1983 35D, High serial # model.
The travel relief valves are set at 2500 psi.
Thanks again, Sheepfoot. I made the switch, and it didn't work. The track doesn't spin in either direction. I elevated the track first, just to verify it worked in reverse, which it did. I know I have water in the fluid, and every time I drain it, water comes out. Also, there was a good bit of varnish in the filters when I changed them (I purchased the machine last April). Could Ice or varnish be an issue, or is the pressure so great, it would push it out of the way? Thanks for all your help. Steve
Ice can cause some issues, and I have seen the varnish in many of the old drott filters. I would pick up two caps and plugs, 37* #12 and unhook the hyd lines at the tube to hose from the valve. plug them and start the engine and try the travel lever to see if it has a load sound. If you have a load sound re hook your tube and line. Remove the cover at the drive motor and plug the two lines to the drive motor and check for loading again. If you have loading you have a possible drive motor issue with oil leaking off into the case drain. If no loading you may have a seal blown in the swivel. You can also switch the drive motor from the rt to the lt side and see if the problem switches sides. While the motors are out you can check the short coupler between the hyd motor shaft and the input shaft on the final drive. These have a trend to wear/ strip out causing no movement or very little. Be careful when sliding them out because the become razer sharp on the internal splines and will cut your finger if you stick your finger inside and try to slide it out and it does not move. Also if you look at the outside frame at the sprocket end, look inside and you can see the big nut that holds the two pillar blocks and sprocket on the shaft, start the engine and move the travel spool to see if the nut is turning and the sprocket is staying still. That will tell if the axle to sprocket splines are stripped. More later if needed.