Caterpillar doesn't know what to think of this. Seeking some advice...
The machine will drive forward just fine. If you try to turn left(right track operating), the brake grabs and eventually locks up due to loosing pressure. It turns right just fine. I have rebuilt and resealed the right hydraulic drive motor.
If I tee into the line with a gate valve and a pressure testing gauge, I have 450-475 PSI at the hydraulic motor. I can shut the valve and it will hold the pressure at the hydraulic motor and operate without locking up. I can move the set up to the left hydraulic motor and lock the pressure in the motor seeing 450-475 psi at the left hydraulic motor. The machine will operate just fine. When you let the system flow through lines for the parking brake together without the valve closed the psi at the right hydraulic motor instantly drops to 200 psi and the motor locks up. When the two motors run in unison besides going forward and backward, the pressure bleeds off internally. When you isolate them they work just fine.
Does anyone have any ideas of where to go next? I'm not really sure how the brakes on this machine work and what changes and releasesthe pressure allowing the machine to turn. I don't know where to go. If you have a hydraulic routing diagram that would be very helpful, but any knowledgeable advice will be much appreciated. At this point Caterpillar is telling me to buy a $1500 service manual...
The machine will drive forward just fine. If you try to turn left(right track operating), the brake grabs and eventually locks up due to loosing pressure. It turns right just fine. I have rebuilt and resealed the right hydraulic drive motor.
If I tee into the line with a gate valve and a pressure testing gauge, I have 450-475 PSI at the hydraulic motor. I can shut the valve and it will hold the pressure at the hydraulic motor and operate without locking up. I can move the set up to the left hydraulic motor and lock the pressure in the motor seeing 450-475 psi at the left hydraulic motor. The machine will operate just fine. When you let the system flow through lines for the parking brake together without the valve closed the psi at the right hydraulic motor instantly drops to 200 psi and the motor locks up. When the two motors run in unison besides going forward and backward, the pressure bleeds off internally. When you isolate them they work just fine.
Does anyone have any ideas of where to go next? I'm not really sure how the brakes on this machine work and what changes and releasesthe pressure allowing the machine to turn. I don't know where to go. If you have a hydraulic routing diagram that would be very helpful, but any knowledgeable advice will be much appreciated. At this point Caterpillar is telling me to buy a $1500 service manual...