Older 843. Starts up and drives fine four the first 5 minutes. After that, left side drive forward gets real weak to no power at all. Right seems OK and reverse left and right are strong all the time. Has a new main pump. Talked to bobcat, he thought it was the left side drive. I bought a used one and still have the same problem. I checked the linkage from the sticks and it looks OK unless i'm missing something. Any ideas? thanks
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mrfixitpaul
Well-known member
- Joined
- Mar 28, 2009
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- 365
Does it have straight linkages or hydraulic servos for the steering?
Swapped the replentishing valves and the trouble did not follow.Straight linkages. No hydraulic servos
I have no idea if this machine has suction line filters or not, but this symptom sounds exactly the same as the older 73x and early 74x series. There was a hidden filter that over the years would fill with junk and the machine would work ok for a while, then when warm it would loose power and simply scream its head off. It refused to drive up hills, changed or cleaned the filter and it was perfect. Could your have a filter there somewhere?Swapped the replentishing valves and the trouble did not follow.
As you have changed the pump, and installed a used motor, there really isn't much else it couuld be.... And its only causing an issue on that one side?
mrfixitpaul
Well-known member
- Joined
- Mar 28, 2009
- Messages
- 365
I have worked on a bunch of 843's and never saw a bronze filter on one, but there could be one if you can find a port block of some kind...can't remember if there is a port block on the 843, but if it has linkages it is an older 843 model. There is the gearbox that the motor bolts up to but I don't see how that would be intermittent. I'd try swapping the known good motor to the bad side and see if it works.I have no idea if this machine has suction line filters or not, but this symptom sounds exactly the same as the older 73x and early 74x series. There was a hidden filter that over the years would fill with junk and the machine would work ok for a while, then when warm it would loose power and simply scream its head off. It refused to drive up hills, changed or cleaned the filter and it was perfect. Could your have a filter there somewhere?
As you have changed the pump, and installed a used motor, there really isn't much else it couuld be.... And its only causing an issue on that one side?
yes problem is only on one side. the manual points you to the replentishing valve swap procedure(if trouble moves to other side, replace valve), but doesn't go any further. your exactly right, it refuses to drive forward up a hill. will back up a hill real strong. i will check for that filter and may order 2 valves. the valves looked good but it on more thing to rule out and they are probably cheap. i still think its something else. i hate to take it to the dealer he wanted 1500 for the drive motor(used 350) and 1000 labor. the main pump was 1000 and 1000 labor. i'm going to run it for a little and see if i can find something that's getting hot. i will ponder it some more.I have no idea if this machine has suction line filters or not, but this symptom sounds exactly the same as the older 73x and early 74x series. There was a hidden filter that over the years would fill with junk and the machine would work ok for a while, then when warm it would loose power and simply scream its head off. It refused to drive up hills, changed or cleaned the filter and it was perfect. Could your have a filter there somewhere?
As you have changed the pump, and installed a used motor, there really isn't much else it couuld be.... And its only causing an issue on that one side?
the serial # is 5020-m-12060 i think it's around 1990. just a 843, no letters.yes problem is only on one side. the manual points you to the replentishing valve swap procedure(if trouble moves to other side, replace valve), but doesn't go any further. your exactly right, it refuses to drive forward up a hill. will back up a hill real strong. i will check for that filter and may order 2 valves. the valves looked good but it on more thing to rule out and they are probably cheap. i still think its something else. i hate to take it to the dealer he wanted 1500 for the drive motor(used 350) and 1000 labor. the main pump was 1000 and 1000 labor. i'm going to run it for a little and see if i can find something that's getting hot. i will ponder it some more.
I still suspect a bad seal in the motor....the serial # is 5020-m-12060 i think it's around 1990. just a 843, no letters.
One last thing, check the relief for that side, if the spring is broken, you won't generate pressure. Can you swap the hoses at the motor? it will be backwards but it will show if the loss of power is the motor or between the pump and motor.
Going to swap the hoses tonight.I still suspect a bad seal in the motor....
One last thing, check the relief for that side, if the spring is broken, you won't generate pressure. Can you swap the hoses at the motor? it will be backwards but it will show if the loss of power is the motor or between the pump and motor.
Swapped the hoses on both side. Now it's weak in reverse left side only. Push sticks forward to drive in reverse takes awhile to get use to. Any thoughts?Going to swap the hoses tonight.
Did you just swap the hoses to the motor or did you swap motors? You said the problem moved from reverse was strong on both, now you swapped hoses now reverse is weak. I would start by checking the relief for the pump, see if its broken. They will have a relief valve on both ports to limit the pressure to about 5,000 PSI, if a spring is broken, or a damaged seat it could cause the problem you are having.Swapped the hoses on both side. Now it's weak in reverse left side only. Push sticks forward to drive in reverse takes awhile to get use to. Any thoughts?
First i changed the left side drive motor with a used one. left side drive forward was still weak. then i swapped the hoses on the left side drive motor. weak left side drive in reverse. i think that rules out the drive motor. will check the relief for the pump.Did you just swap the hoses to the motor or did you swap motors? You said the problem moved from reverse was strong on both, now you swapped hoses now reverse is weak. I would start by checking the relief for the pump, see if its broken. They will have a relief valve on both ports to limit the pressure to about 5,000 PSI, if a spring is broken, or a damaged seat it could cause the problem you are having.
