So we had the rear gasket go on the tandem pump and it was leaking a fair bit of oil, so I decided to bite the bullet and do the repair, we pulled off the pump, took out the rear shaft, and replace the gasket, put it back together, and now we don't have forward on the right side drive, the left side works perfectly, and so does reverse on the right side, but no matter what we do/check the right side forward is not working, We did check the roll pin to make sure it was sitting in the slot it is suppose to be in, still nothing. Anyone have any other ideas what could cause this? I have talked to my local Case dealer, and they keep telling me it is a shop pump, and to replace it?!?! ***??? it was fine before it went to get the gasket replaced, I think they are just trying to screw me over.
mmmmmm..... not good. Normally I would say swap the reliefs for the right side & see if the problem goes to reverse. Fact that it was OK when you pulled it apart & not when it went back together is a worry...... You pulled shaft to replace the seal? - Not necessary....... "The roll pin"???? where exactly is it located? There are 3 needle rollers that hold a collar/ring where the shaft goes into - is this what you are speaking of? When the cover went back on, how did it feel? There is normally the last 4-5mm before it contacts the housing that it springs a little & must be pulled together with bolts, Did you check if shaft could keep turning during assembly process?
the piece that goes down from the control arm has a roll pin on it that sits in a 1/4inch grove. We were very careful of the 3 needle roller pins that you are talking about. we checked most everything you suggested, although switching the relief valves is a great idea. I am at a loss otherwise, however I do have it going in to a shop that has the ability to operate the pump from the bench, I am hoping they have some ideas.
So took the pump to the shop, and $240 dollars later they told me everything was working fine and they didn't see any problems, to install it, and then if it was still doing it to call them in where they would come out and take a look at it. Got it back to the shop and put it in, and of course now it works!!! ***, so the question now is, does anyone have a theory why it did what it did?
You probably already thought of this, but how about air in the system? I think most hydraulic pumps, especially used ones don't create a whole lot of suction before they are fully primed.
I'm bettin you did not have the swash plate seated properly in the guide groove or one of the teflon? bearing plates came off and was binding the swash plate from moving, this can happen, don't ask me how I know. LOL, sounds like you got hooked up with a good shop at least, it works and not all that costly considering. Mel