Steve@Advance
Well-known Member
I've been doing some repairs on the 753 Bobcat skid steer. I'm hoping someone on here has been into one before and can save me a lot of guess work!
Right now I've got the engine disabled, waiting on parts that will be here next week.
But the biggest problem I need to look into is the hydrostat system.
This has been going on for a while, seems to be getting worse. The right drive is weaker than the left. If both arms are pushed full forward, it wants to curve to the right. We've been able to live with this, it's not too hard to correct by just pulling back on the left a little. I haven't gone through the linkage adjustment procedure, but I think that is ok. Everything feels solid and it always returns to neutral.
But what has gotten worse is on cold start up, the steering is really jerky and difficult to control, somewhat on the left, but worse on the right. When trying to make the first move on cold startup, I move the steering arms, (gently because I'm usually trying to ease it off the trailer). I can hear the engine load slightly, the left tries to move, the right feels like it's stuck. Pull back further, further, suddenly it grabs and takes off all at once! Seems to do the same going forward or reverse. Once it gets to moving the grabbing gets better, but never quite right.
I have the shop manual on CD. The trouble shooting instructions are not the best, mostly how to interpret diagnostics with a reader I don't have, most of the illustrations are too dark to see. Still it's better than nothing!
I was at the dealership today getting some parts. I talked to one of the techs, he seemed knowledgeable. His suggestion was to disconnect the hoses from the hydro motor, cap the lines, start the engine and move the steering arm for that side. If this action kills the engine, it proves the pump is good, and the motor is bypassing. This makes perfect sense, I plan to do this test on both sides next week when I get the engine running.
But, if the pump fails the test... Does anyone know how many pumps are there? One for each side or a common pump for both? Is this the same pump that operates the lift and bucket? (Those work as they should) Is there anything else to check, like pressure regulators or relief valves?
Thanks, I follow up next week when I can run some tests!
Right now I've got the engine disabled, waiting on parts that will be here next week.
But the biggest problem I need to look into is the hydrostat system.
This has been going on for a while, seems to be getting worse. The right drive is weaker than the left. If both arms are pushed full forward, it wants to curve to the right. We've been able to live with this, it's not too hard to correct by just pulling back on the left a little. I haven't gone through the linkage adjustment procedure, but I think that is ok. Everything feels solid and it always returns to neutral.
But what has gotten worse is on cold start up, the steering is really jerky and difficult to control, somewhat on the left, but worse on the right. When trying to make the first move on cold startup, I move the steering arms, (gently because I'm usually trying to ease it off the trailer). I can hear the engine load slightly, the left tries to move, the right feels like it's stuck. Pull back further, further, suddenly it grabs and takes off all at once! Seems to do the same going forward or reverse. Once it gets to moving the grabbing gets better, but never quite right.
I have the shop manual on CD. The trouble shooting instructions are not the best, mostly how to interpret diagnostics with a reader I don't have, most of the illustrations are too dark to see. Still it's better than nothing!
I was at the dealership today getting some parts. I talked to one of the techs, he seemed knowledgeable. His suggestion was to disconnect the hoses from the hydro motor, cap the lines, start the engine and move the steering arm for that side. If this action kills the engine, it proves the pump is good, and the motor is bypassing. This makes perfect sense, I plan to do this test on both sides next week when I get the engine running.
But, if the pump fails the test... Does anyone know how many pumps are there? One for each side or a common pump for both? Is this the same pump that operates the lift and bucket? (Those work as they should) Is there anything else to check, like pressure regulators or relief valves?
Thanks, I follow up next week when I can run some tests!
