D19 snap coupler arms

Sounds like the tube that feeds the lift cylinder has a leak in it and will need to be replaced.

If it is like a D-17 the tube is inside the rear end

I'm having some trouble with the hydraulic lift on my 1962 D19 diesel also.  I have the 3 spool valve, but the arms won't lift when I pull up on the inner valve lever.  However, if I move the traction boost lever to the top, the arms will go up slowly and lift a fair amount of weight with my boom-pole, so the traction boost plunger in the pump is working properly.  The hydraulic lift lever will lower the arms.  I put a pressure gauge on the remote port for the lift arm valve, but I didn't read any pressure from the main pump, and the traction boost plunger put out around 1900psi if I remember correctly.  Does this sound like a stuck relief valve, or check ball problem?  Do I just need my control valve rebuilt, or is it possibly a pump problem?  I'm thinking about disconnecting the hard lines from the hydraulic pump and plumbing in a loop with a gauge and ball valve to see if the main pump is putting out any pressure.

Edited by Brad Kelley - 02 Jun 2010 at 8:39pm

Brad, be sure the knob below the single hyd coupler is scewed all the way in.  It sounds like the either the relief valve is out of adjustment or the pump is not pumping on the 3 pistons.   Its defenatly not a check ball problem, the check ball keeps the arms from dropping.  Try screwing the relief valve in a turn or two and see if that helps.  Ususally a relief valve will let it build some pressure but will open to soon and wont lift a load, it sounds like you may be pulling the pump to have a look at it.    Ive got two D19s a gas and a diesel, yours sounds just like mine!!!! 

Ya know Matt, I halfta to go home and look at my D19,   Im sure its on the vavle stack, but exactly which one Ill hafta look!!!

Thanks for the replys guys.  Yes, the relief valve adjustment is on the back of the valve stack above the left hand remote port.  My father had the cap off and gave it a few turns both ways, but it didn't change the reading on the test gauge or change the operation of the arms.  I also adjusted the control knob on the valve both ways, and it didn't make any difference.  When I get a chance I'll try to plumb in my bypass loop and see if there's any flow, but I guess if there isn't I'll be pulling the pump to see what's going on inside.

That was the next place to go Brad.   Not to often do the rollers go bad as they run in oil all the time.  You might want to take it apart and replace the oring and be sure to look at the check ball springs as they are pretty lite and are probably broken.  Dont be afraid, just lay it all out on the clean bench, clean it up, put it back to together. A parts book helps a lot on reassembly.   good luck