Cub Cadet 129 won't move after sitting

[wilypence]

The Cub Cadet fever bit me again and I ended up with a 126 and 129 that I was able to get working. The 129 is my first hydro Cub, and well, the jury is still out if I prefer gear drive or this hydro.

I don't know the history on the 129, but it seemed like it was restored maybe 15 years ago and then it just sat unused. I rigged it to just see if I could get it running, and after that was successful I went through all the normal maintenance items on the engine: carburetor, fuel lines, ignition system, battery, oil, and going through all the maintenance items. It fired right up and everything worked 100% except for it was leaking hydraulic fluid pretty heavy, it turns out from the relief valves.

When I bought it the tunnel cover was missing which I was afraid was a bad sign. I replaced the hydro fan based on feedback from this forum since all the blades were broken off. While I had the driveshaft out I went ahead and replaced the flex disc and hub. I sent the relief valves to MachTech and after replacing those, pulling the rear cover, and replacing the fluid and filter, everything worked great and it hasn't leaked a drop of hydraulic fluid since. Over winter break I ran it all over the yard in forward and reverse and the hydro worked fantastic at all engine speeds. It never missed a beat since I serviced it and had the relief valves fixed.

However, it sat for about 2 weeks or so without being run. When I fired it up to mow the other day, it would not move in reverse or forward at all. I checked the normal things, making sure the hydraulic fluid was topped off, checking to make sure I could see the driveshaft on the output of the hydraulic pump was turning, etc. I pulled the relief valves and they look fine and free of debris. I even tried pouring some hydraulic fluid down those 2 holes where the relief valves install, and even tried some compressed air in the fill hole thinking the pump just wasn't priming. Still no movement at all, and I don't even notice any noises when I try and go forward or reverse. Someone converted it to foot control, and I confirmed the linkage is operating the lever going into the hydro unit properly when I work it through the range of motion. I pushed it (relief valves are the auto release style) a good 30 yards to see if that would help prime the pump.

The only thing I haven't tried is to pull the new filter I installed to see if it was blocked. When I originally pulled the rear cover the unit was actually very clean with no major debris in the bottom of the rear axle housing. I carefully wiped it out and made sure not to leave any paper towel remains behind. I used a Wix 51410 hydraulic filter and Traveller hydraulic fluid from Tractor Supply. I have a Napa 1410 hydraulic filter on order at my local store to swap the current one out.

I'm in south Florida and this winter it has gone from cold (nearly 30 degrees) to hot (got up to 80 degrees today) over the course of a couple days. I keep the current Cubs in a portable garage outside, and have noticed a lot of sweating on the outside of the rear axle from the temperature swings. It's possible that there's condensation on the inside, but I can't imagine there's a whole lot. Does anyone have any other ideas to try? I have a hard time accepting that there's an internal failure since it was working so well before being parked a couple weeks.