49 SC Hydraulic problem--posting again

Why does it work when you first put the fluid in and then stop? What is the grinding, grating sound? I have the parts and service manuals (Jen Sales), but do not see a schematic for the 49 hydraulic pump workings, only the old motor lift. How are the gears that run the chain drive secured on the shaft? Pinned through? Half moon keyed? Could that be sheared? Since it runs at first and not when pressure builds up, could that be a possibility? If so, how is repair done??

Any suggestions would be appreciated, as I'm out I'm out of ideas, since I have no schematics and knowledge of the inner workings of the mechanism.

You may have a stuck relief valve and a cracked pump body. I would think that it would spray oil all over the inside of the sump when trying to lift or lower. You can check by observing with the fill plug out. Borrow a service manual that covers hydraulic pumps. You may find your answer in the trouble shooting section. Good luck.

Before I bought the tractor, it had been used on a loader and was plumbed for that loader. The left side port and hose had a hydraulic snap on and release type coupler and obviously was coupled with the loader cylinders. The other port and hose was fed back into the resevoir with a T at the filler plug.

I am now trying to use it with the "Original" working cylinder to work both ways--up and down. Could the previous owner have modified the pump or simply through non use on the right side of the pump the relief valve "got stuck"? My understanding of this type pump is that it should work both ways and give relief both ways. Is that correct?

As I've stated in previous posts, there seems to be a build up of pressure on the right side hose and port that locks the system up. Is there a bypass in that port for the fluid to flow? The spring and ball are in there so it can't flow through that opening. I've thought of taking the spring and ball out, but then I have no check valve for down pressure. There must be some bypass of something to allow fluid the flow the other way. Is that the relief valve, you're talking about?

Is the cylinder attached to an implement? If so is it possible the implement is too heavy for the cylinder. The Case pump is only rated at around 800psi, substantially lower than modern equipment, as such you will need a much larger diameter cylinder to do the same work. The pump would probably make a grinding sound and bog the tractor slightly if it were put under full pressure.

If this is the first time using the setup, I suppose it would be possible to have blown a seal, internal to the pump, if it were forced beyond its maximum pressure.

Are you running the correct oil in the system? I think 30wt is recommended.

I will wait to try it again until I hear from you.

It seems that it is not releasing on the down pressure side. When I take the hose off that side, there is a lot of pressure there and the first time I took this hose off (quickly), it squirted out with a vengence (the pump was not engaged nor the tractor running). It seems to me that should not be the case. Is there some release valve not working?