D6 Hydraulics Problem

[belsheen]

Hello all, this is my first post. I've got a hydraulic problem that I wonder if anyone might have some input on. Trying to buy my uncle's old '54 D6, which looks to be in suprisingly good shape. Once I fixed a fuel/carb issue with the pony motor, I got it fired up (after it had been sitting a year) and the diesel ran very smooth. However, I couldn't get the hydraulics to raise, although they did push down somewhat, lifting the front slightly. I'd be interested if anyone had any ideas. On pre-check, the fluid levels all looked good, and no visible leaks anywhere. BTW: It had been parked with the blade resting on the ground.
 

[NCWayne]

Can't say for sure what type pump they used on the hydraulics on that machine, but I know the vane pumps CAT often used on their equipment would lose their prime if left setting for a period of time. Too, I have had the vanes stick and not want to pump properly right off.

The first thing I'd do is look on the inlet or the outlet side of the pump and see if there is a small fitting/plug that you can remove. With the plug out pour in a quart or two of hydraulic oil, and replug the hole. I've had to repeat this proceedure several times on occasion to ever get the pump to actually pick up, but give a couple of shots of oil, it never failed to work.
 

[Old Magnet]

The Cat system uses the #46 hydraulic control with the vane pump built into the tank. They are sensitive to oil viscosity and can take a while to pump if the oil is to thick or contaminated. Drain some oil from under the unit and see what you have. Yes, it is possible for the vanes to stick thus no pumping.
 

[belsheen]

[belsheen]

Thanks for the info. I did let it run for 1/2 - 1 hour, and tried to keep working the lever, thinking that if it warmed-up enough and I worked it enough...... (someone thought perhaps air could be in the cylinders/system)... but I didn't get anywhere. At least the oil at the dipstick appeared low viscosity, especially after it warmed-up (of course). I'll take your advice, and try to find a drain and see what's there.
Any idea where it's located on that specific unit.
 

[NCWayne]

The hydraulic control systems on those machines were seperate from the machine itself when it came to parts. No guarantees but I do have a few of the parts books for the hydraulic systems so I'll look when I get back to the shop and see what I've got.
 

[Old Magnet]

There are two magnetic drain plugs, bottom front of grill, one on each side of center. Be a good idea to check the filter also.