I have a cat 246b Skid steer that was starting to make a whining noise when ever you would go forward or reverse. if you went down hill the whining noise would go away till the unit was back under load. Lifted the cab and snapped some pictures and sent them to a coworker who worked for cat for awhile and he said to check the speed sensing pressure. I noticed that the protective cap on the adjustment stem on the speed sensing valve had marks on it like someone had played around with it before. Got the testing procedures from cat and charge pressure is within spec @460 psi and the speed sensing port was reading zero. tried adjusting the stem on the valve which looked like it was backed all the way out and adjusted it in and no change to pressure. Called Cat and they said if you have zero psi there then you would have no pilot controls so suggested that i remove the test port and see if it was plugged. removed and tested ok. started up the unit and still zero but now I have no pilot control. unit will not move. Called cat again and they recommended pulling the valve out and seeing if the spring is damaged or the washer was damaged. Pulled it out and seemed like there was sufficient pressure and no damage anywhere. reapplied and still zero psi. so right now I have a 7000lb paper weight and no ideas. might have a lead on a damaged skid steer and going to take that valve from it to try in mine.
What’s the serial number? Is the hydraulic tank full?
Hi, are there fault codes ?are the fault indicators on? Are you sure you used the correct test point? see below if so you may have a worn out charge pump or a large internal leak the charge pump is easy to remove and dismantle to check as a first step second I would blank off the line going to the park brake /two speed if equipped and recheck pressures I have include an hydro schematic as well regards Mark
Ser# is PAT03645 and tank was full when it stopped moving. after removing the speed sensing valve for inspection I didnt expect fluid to drain from the tank and lost about 4 liters of fluid. Everything else works fine
No fault lights on. Yes I took the pressure from the speed sensing tap location which has a T fitting. One side is the quick connect and the other side has the line that runs to the pilot controls. hopefully the pump is fine. only has 3000 hrs on it. I did also change the filter so dont know if that would have any affect on the system. I hooked up a line and valve to my pressure tester to see if anything was coming from the speed sensing port and it was just a slow stream of fluid. where is the line for the park brake located? thanks for your response so far. adam
the park brake/two speed valve is mounted on the left hand frame rail under cab
does it matter if its only a single speed?
No, just trying to eliminate leak paths
Sorry for the late update. So picked up a new Speed sensing valve for $1500 . Refilled the hydraulic tank and fired up the unit. Finally got pressure on the guage and adjusted it to spec.then went to go move some hay bales and 40 feet later it starts to squeal on my. Happens in forward and reverse. Figure it's the charge pump now but it had good pressure before. It's never ending with this thing