Right track stuck in reverse. 262B

[Forrest Whittington]

Thanks for your help. I’m at a total loss. there was some poorly managed maintenance done between the engine and pump. Upon receiving the equipment back the right track now is stuck in reverse while the left is dead. Left stick doesn’t do anything.
Is there a schematic I could trace crossed lines? Or some type of flow chart?
What’s that little electric motor under the left lever? Thank you for any wisdom you may have.

 

[Nige]

What’s that little electric motor under the left lever?

That “motor” is a box containing four position sensors that send signals from the joystick to the ECM so that it knows what you want to do and moves the hydraulic control valves accordingly.

there was some poorly managed maintenance done between the engine and pump.

Care to elaborate.? Were hydraulic hoses replaced.?

For a start try posting a Serial Number. It helps narrow the field down somewhat and would also get you a hydraulic schematic.

 

[Forrest Whittington]

Thanks for the response. I’ll get the SN tomorrow. No hoses were replaced. Some sort of Round teflon plate between the pump and engine was changed. And had worked before hand. It’s still at idle but when you raise the rpm the right side tracks backwards.
I’m sorry I couldn’t be more specific. Could maybe be Electricial?

 

[Forrest Whittington]

Cat0262bppdt02031 is the product identification number

 

[Nige]

Some sort of Round teflon plate between the pump and engine was changed.

OK, so it has had the pump drive coupling replaced.

It’s still at idle but when you raise the rpm the right side tracks backwards.

Have you tried moving the joystick for the right side away from the neutral position towards forward when the wheels "track backwards" to see if some sort of input on the stick will stop the movement.?

 

[Forrest Whittington]

Yes sir. It appears to have no response whatsoever.

 

[Nige]

Are there any warning lights illuminsted or alarms sounding when you start it up.?

I don't know about anyone else but it seems to me like time to get the electronic diagnostics hooked up to it and read whatever Codes might be present. Options are a Cat dealer or a local independent mechanic who has Cat ET.

If the machine was working correctly before the drive coupling failure then it seems likely something has been damaged or mis-connected during the course of the repair work. Either that or a massive coincidence.

 

[Forrest Whittington]

I’m believing something was hooked up improperly. Or hoping so actually.
No alarms other than parking break switch. But the key doesn’t start it. A guy jumps the solenoid with me in the cab. We’ve only done this once to verify the engine runs and working hydraulics. This being the one time I found the current problem.
I’m sure I can repair the ignition problem. But the hydraulics are another world to me and the cat guy here wants $180 an hour just to take a look.

 

[Nige]

I’ll send you a copy of the electrical schematic. That ought to help you with the issues around not starting from the key.

 

[Forrest Whittington]

Thanks. I looked it over and got it to crank with the key now.
Turns out if I’m correct in reading it’s a hydraulic control joystick. The servo has only two wires coming from it.
To get it home I had to reverse the hoses to the left and right motors to get it to drive forward and swap them back to get it off. The right side is definitely getting more power than the left but when full throttle it seams to balance. Maybe a seal is leaking by or something stuck inside either the joystick or pump?

 

[Nige]

The attached is a breakdown of what's inside it. A leaking seal is usually indicated by oil leaking outside, but an internal leak is possible I suppose. As you can see there are various seal kits available for it.

 

[Forrest Whittington]

Thanks. I took it apart today and didn’t see anything wrong. So I reversed the hoses on the joystick to create a poor symptom on the right side. It did not. so the problem must be in the drive pump.
looks like I’ll be pulling it apart.
Is there a breakdown or an explanation of what does what inside the pump? I bet there’s a repair kit for the drive pump.

 

[Forrest Whittington]

I’ve solved the mystery!!!!
When the guy put the hoses back he must have slid the hose end (which was kinda sharp) over the o ring of the joystick and sliced a tiny sliver off of it inside the hole.
I first removed the smaller sized Allen screws on the outside of the housing which holds a small steel ball. All the steel balls came out with the screw and a bit of fluid dripped with the break save one that was stuck and was dry with the thread break. That one controls the left track forward.
After playing with it a bit it finally fell out and prompted me to break down the three housing parts. The first inbetween all the bottom facing male threaded fittings. Then what that Allen bolt threaded into inside is also the very fashioner that holds the third and top most part of the housing which contains the push rods. That same stuck ball was inline with a push rod that was firmly straight when the other three fell as if relaxed. Small work back and fourth resulted in a similar relaxed feeling such as the others.
I used a torch tip clearner to clean up anything stuck in the small brass flathead inserts (can’t miss them) and what do I find where the push rod rest on that small brass threaded orifice? A tiny sliver of rubbers no bigger than that tiny sliver of rubber I observed initially.
So this is why it worked fine. The mechanic swapped the pump drive coupling, hoses went back, and it didn’t work until now.
Once I decided to open it up it took all but 45 minutes to identify how to open it without the springs flying out (careful), correcting and having it installed. Super easy.
After looking closely at those small Allen screws which has two holes drilled perpendicular up and down but 90° different from each other, I believe these to be where you adjust the flow volume between the two hoses for when you are turning wile going forward or reverse.