I have this 70's International Backhoe. It is a 3600 Series A. Tractor starts and runs fine. Aux. pump works great all attachments work. Seems to me the outriggers are a little weak, they struggle to lift the machine off the ground. They need the bucket to help get them all the way down. I have changed the hydraulic/trans fluid. I even cracked lines to get all oil from the cylinders and lines. The system was contaminated with water. I changed both of the hydraulic filters, the element that is inside the transmission and the element in the canister that is in the engine compartment above the charge pump. This model has the foot pedals on the left, one for forward and one for reverse. On the right is your speed ratio(acceleration) Pedal,right one, and the left one is your brake. When depressing the forward pedal to the reverse pedal, the cam they are connected to moves freely and smoothly when the engine is running switching from forward to reverse. When the engine is off, they will not budge. This makes me believe that the pump servos are tilting the plate from forward to reverse. However when the Speed pedal is depressed nothing happens, There is no feel either of anything happening. This connects back in the range transmission, and goes from there inside to the acceleration valve, for the forward and reverse drive pressures. No change in engine tone or rpms. When the wheels are off the ground they can be rotated with the Range in Neutral. Once put into H or L you can hear the engagement and the wheels will not budge. This leads me to believe the problem is in the speed ratio or shuttle valve. But for some reason I am thinking a stuck High Pressure valve, as it seems 0 drive pressure is building up. Once again if I had the proper tooling this would be a breeze. This seems to be a hydrostatic issue. I do not have the proper gauges to trouble shoot this transmission, or time. It seems that time is the factor here. Going through some tough employment times, and I am needing to get this moving, to sell. I have the Manual from case on these Hydrostatic drives, and there is a lot more involved in it then my little tool set is equipped for. What I am looking for are any suggestions, or possibilities I may have overlooked. Or a professional opinion. I am located in East Peoria, Illinois. I would be willing to pay for a Mechanic to come out, for an estimate of whats wrong, and/or to possibly to fix it, provided that it is nothing too major. You can PM me what your rates are or what you would like, to come out and take a look. I am friendly, fast to learn, and can help, or stay out of the way. I am in East Peoria, IL hopefully some members are close to here. Or I can be reached at 309.369.8453 Thanks, any help or comments are greatly appreciated. Rob
New Findings Well, I just tested the charge pump port. My readings were 175-190 p.s.i. Unfortunately I am using a 3000 psi gauge so it is hard to get a super accurate measurement. From my understanding from the manual this is with in spec. Now where do I go from here. The servo Pressure, or the high pressure off of the foot-n-inch valve? I will do both now and get back with the results. And I will be using the 5000psi gauge for the higher tests if needed. Thanks in advance
Servo pressure was 400psi. With engine at 1200 or so rpm.
I'm not backhoe mechanic but if your charge pressures are OK, I'd look to the main pump. As you stated, you can't even get the outriggers down without help from the bucket. If the outrigger won't jack the tractor up with ease, what affect will that have on the hydrostat drive ? Perhaps it might help to address pump pressure first, everything else might fall into place. Could be a relief valve issue. Good Luck with it ! Gene, Pearl River IH 3400A Backhoe
Is there a clutch going to the transmission? In the parts diagram it shows the pump to a pressure plate. The out riggers I think I spoke a little soon on, I ran all of the cylinders through there motions, removing the air from bleeding the fluid out of them when I changed it. Cycled everything and They seem to be doing better now. I think they need to be in dirt, instead of my concrete driveway. Seems a little hard on it. Just taking it easy on the machine and learning as I go. I guess this is where a flo rater would tell the whole story as to pump efficiency. I see a spin on filter off of the multi valve going to the hydraulic oil cooler. Can a plugged cooler And a stuck ByPass Valve cause the machine not to move? I put the pressure gauge on on the foot n inch port I believe , to be the drive pressure and get nothing. Can a bad foot-n-inch valve keep the tractor from moving? Can it possibly be a high pressure forward or reverse valve? The auxiliary hydraulics seem strong boom lifts up tractor, and Moves tractor, No Noises and the out riggers are working now. I am thinking about taking off the plate on the transmission to access the forward high pressure and the reverse relief valve. Not sure what to look for, but maybe the high pressure one is stuck or the check ball rusted/ gummed from sitting? Any thought are welcomed thanks