Case Case-o-matic Oil Pump Problem

Bear in mind that the COM transmission worked perfectly before I started. I am restoring the instrument cluster on a 1960 830 gas tractor. The torque converter temp gauge needed to be replaced. The temperature probe came out easily from the reducer that screws into the manifold. Guess what? The new probe kit was not an exact replacement of the old one (different thread size of the temp probe). Therefore the reducer needed to be removed and replaced with the new one that came with the kit. It broke off as I tried to remove it. I had to then take off the manifold and take it to a machine shop in order to remove the remainder of the threads. Since the torque converter pump bolts on to the inside back of the manifold, I replaced all the gaskets and pump seals. When I put it back on the tractor, I primed the pump through the 1/8" MIP pipe plug hole towards the top of the manifold. I started the tractor and drove it around for about 5 minutes. The COM seemed to work perfectly (pump pressure was good).

I shut it down for a few minutes and then restarted it. I have had zero pump pressure since. I tried repriming the pump with no luck. I assume that before I started, the converter oil contained no air within the entire loop. I also assume that due to pump wear, the pump can no longer purge air out of the tube going to the pump and draw the oil up and through the pump and beyond. I bought a vacuum pump and plan to connect it to a temporary shutoff valve going into the 1/8" MIP hole mentioned previously. Hopefully that will at least remove the air in the tube between the pump and the bottom of the case. Once the COM starts working again, I will replace the shutoff valve with the original pipe plug. Has anyone experienced similar problems?

I don't have a clue but try posting on the Case forum,there's some real smarties there.

wonder if you have a piece of metal or debris holding bypass open allowing oil to leak off

I got a service manual on CD, and it appears that the no oil pressure problem is caused by one of 2 possibilities. I also changed the oil in the process. The original oil was very black (dirty). After changing the oil (2.5 gals. out of 4 total), the mixture of new and old also became black. Coupled with the fact that the new oil contains detergents, perhaps debris is indeed causing the relief valve to stay open. The other possibility is that I used the old seal in the intake tube as it bolts to the pump. All other seals and gaskets were new, except for that one. I will order a new seal and new relief valve and try it again.