1989 Bobcat 743 Hydraulic drive issue

[Sgabino2]

I have a 1989 bobcat 743 that I use on my farm down in south Florida. I was working the machine the other day when I blew a hose that goes to the right side drive motor. The machine was going backwards when it blew, I was grading some dirt. I replaced that blown hose along with the two other hoses for that drive motor and one additional hose that I saw could use replacing. All hoses were connected back properly and the machine was topped off with hydraulic fluid.

The issue now is that when I attempt to start the machine the right side drive begins to turn in reverse, like the machine is stuck in reverse on that side. As the starter motor cranks the right side tires begin turning back. I looked over all linkage and can confirm it’s not a linkage issue. I inspected the shuttle valve on the right side drive and it appears to be clean and actuating. Not sure how this operates. Any assistance is much appreciated

 

[flyerdan]

That is an odd one. Perhaps the shuttle valve lost pilot pressure when the hose let go, and since the new ones are empty it will take some cycling to get fluid in them again.
Can you get all 4 wheels off the ground so it will start easily? I'm thinking that if you can run it for a few minutes forward/backward with the wheels up it will purge the air and go back to normal. At least it's a fairly easy first step and don't cost anything.

 

[Sgabino2]

Thanks for the reply. The new hoses are filled with fluid because It is turning the right side wheels in reverse. The pump will create pressure as the motor cranks to where it walks the machine backwards on one side as its trying to start. Even if I hold both lever forward while trying to start it will still act the same. Since this issue no other hydraulic controls appear to function I will jack up the machine so I can let them rotate and hopefully bleed or reset the possible valve issue.

 

[nyone]

I bet a hose is hooked up wrong.

 

[Sgabino2]

I bet a hose is hooked up wrong.

 

[Sgabino2]

Ive looked over the hoses and they appear to be correct. When I had the new replacements made they were all specific sizes so can't really have them mixed up as far as location goes. The pump will create pressure as the motor cranks to where it walks the machine backwards on the right side as its trying to start. Even if I hold both lever forward while trying to start it will still act the same. I tried switching the two hoses on the right drive motor and the problem was the same except the machine would move forward on the right side.

 

[oldnslo]

I responded to your post in hydraulics where the picture you posted and labeled shows the rear vane pump connected to the motor which would cause the exact problem you are describing.