Front Loader Hydraulics

I have a Du-Al front loader on my D-15. A couple of days ago it stopped moving, as in won't budge. There was no gradual slowdown in it's movement. I was using the loader for about an hour and it seemed to work 'normal', then it ceased to work at all. I topped off the fluid, but it still won't budge. What should be my next move to figure out what the issue is?I thank you!

im with Dave... The PUMP sucks the oil and pushes to the VALVE.... See if the pump is turning.... if it is, see that the hose out to the pump to the valve has pressure  ( crack one end loose ?)... Check that the valve spools are moving, all pins attached

Edited by steve(ill) - 27 Aug 2023 at 12:21pm

Do you mean to say the tractor stopped moving or loader stopped  going up and down? Does it have a front mounted pump with oil supply in loader frame?             MACK

The loader does leak fluid here and there, not big leaks, but I would not park it on my pristine driveway (if I had one).

Edited by John-Paul - 27 Aug 2023 at 10:22pm

I'm with Nathan on splines stripped.             MACK

the pump sucks oil from an oil tank. Is there a suction screen in the line or inside the tank before the pump ? ........... You should hear Squeeling if the pump is cavitating... If the VALVE is broken or stuck and dumping oil back to the tank instead of sending to the cylinders, you normally will not hear the squeel.

Edited by steve(ill) - 30 Aug 2023 at 7:14am

Rough worn. Out splines will turn pump with no load on pump. Pull a lever and see if pump still turns.                       MACK

Hopefully this is not too long and that it makes sense....So with the engine running, the engine side shaft turns, but not the shaft going into the pump. I was the only one at home, so I was not able to view the pump shafts with a lever pulled. I thought of rigging up a mirror, but....There is the engine side shaft, then a coupler, then the shaft going into the pump. The single spleen on the pump side shaft and the groove that it mates with on the the coupler are both a bit rough and worn out, but I did not see any metal chunks missing. The coupler has two set screws. One tightens down on the engine side shaft spleen and the other down on the pump side shaft spleen. The pump side set screw was missing. I cut down a bolt and used it along with a locking washer to replace the missing set screw, and put it all back together. I started the engine - the pump side shaft WAS turning for maybe 15 seconds, but then stopped. After trying that a couple of times with the same result, I thought I needed to do something else. Two things, maybe, about the connections - first - it doesn't seem like I was getting the engine shaft, coupler and pump shaft all 'compressed' together enough for the spleens to stay securely in the their grooves. The pressure from spinning pulls them apart. And two (which I thought of after wrapping up for the evening)- is that I CAN get a better connection between the pump side shaft and the coupler by simply turning the coupler around. The groove is not as worn on the side that has been connected to the engine side shaft. So I will do this, and get the proper set screws. One thing that seems downright deficient though, is the connection between the pump shaft spleen and it's receiving  groove on the coupler. The shape of the spleen on the pump shaft is triangular (like a shark fin), but the receiving groove on the coupler is kind of shallow and rectangular, so only, maybe, a 1/4 to a 1/3 of the triangular spleen can get inserted into the groove. To keep it there, I think I need to push the whole pump towards the engine until the engine side shaft bottoms out. But to do that I need to shorten the spacers and bolts connecting the pump to the engine/tractor frame. On top of that, the set screws need to be flush with the coupler (they are not flush now) so the coupler can spin while located in the hole of the engine/tractor frame. I know it all held together for years before but I'm not sure how. The coupler DOES permit some range of adjustment, but not enough to have everything compressed tightly. I would have added photos, but I can't figure out how to get them small enough yet to upload.  I appreciate all of your help!

John Paul, your splines on that shaft are GONE and probably the coupler they slide into are shot as well. Good splines and a good coupler have at least one full inch of overlap. They do NOT need to be compressed. They wear out from age and no lubrication of them.

Thank you for the postings on the hydraulics.

Thank you for the resource!

Ah, thank you. All of these terms are new to me. I was born and raised in Illinois. I'm proud of my midwest roots.

Edited by John-Paul - 03 Sep 2023 at 5:26pm