Chinese mini dumper stalling in reverse-what to check?

[oldnslo]

Totally off track (no pun intended) thinking but could problem be with tracks..... Something binding tracks in reverse and stalling hydraulic motors.... BUT works well going forward.... Because the logic for hydraulics to run track motors is the same whether going forward or reverse....

Maybe jack it up and pop tracks off and see what it does, or maybe put it up on blocks so there is no load on tracks...

Interesting thought on track binding but why does it work full speed reverse and not when trying to operate at less than full speed? If this unit has blade on front should be easy to lift both tracks off the ground with blade and bucket and see what happens.

Duhh this is a dumper not a mini ex so jack it is.

 

[2manyrocks]

Track binding or resistance in the track rollers could play into this, but my number 1 suspect is something hydraulic related.

When I first went to the auction yard to load the machine, it had difficulty even lifting the front bucket without tending to stall the engine. It was parked close behind a mini skid steer so I needed to run it in reverse to back away from the mini skid steer, but the engine consistently died in reverse even though the engine itself started easily and ran well. There was enough room to zero turn the machine but that involved several stop/restarts.

Another guy saw me struggling with it. He came over and tried and got the same results.

I eventually got it loaded under its own power and brought it home.

After changing the hydraulic oil and operating the machine a bit more, the front bucket is now cycling much better than it was and the machine will now operate in both forward and reverse by going full stick.

I don't know the history for certain, but I think there's a dealer in the area that imported 20-30 of these that have been sitting in the dealer's warehouse since they were made in 2022. I think they were asking $3,500 and then dropped their retail price to $2,500. There was one that sold in the March 2024 auction for about what I paid for this one, and then this one came along for auction in June.

I mention this out of curiosity whether this time of sitting in the dealer's warehouse with whatever hydraulic oil was in it (it looked okay when I drained it) may have contributed to the hydraulic system tending to stall when feathered? I don't know if the hydraulic oil came from the factory or if the dealer changed it. I mention this because it seems like the machine is doing better just due to being operated?

Will also mention the machine has very little ground clearance and not much protection for the wheel motors.

 

[2manyrocks]

Raising the machine completely off the tracks with the loader and a jack, I see no difference in the stalling behavior. If I try to feather the tracks, machine tends to stall. If I go full stick F or R, it doesn't.

I haven't tried loosening the tracks. I think I will try operating the machine a bit more to see if it loosens up from operation.

 

[oldnslo]

Are the hose ends the same where they connect to the motor and PO check block? If yes could you just loop the C1 & C2 ports together? This would remove the track drive motor from the rest of the circuit.

If you can feather the control that would point towards a problem in the motor or track drive assembly

If engine still struggles or stalls the problem is in hydraulic circuit so maybe do same by looping ports on directional valve together to see what happens.

 

[2manyrocks]

The tracks are slow enough that I am not being jerked around on it by going full stick F and R, but do you think I am I increasing the odds of damaging the machine by operating it when trying to feather the controls stalls it?

 

[oldnslo]

Not sure on damaging anything going full stick but is concern of system pressure stalling the engine and or what are the pressure spikes when you turn, feather etc.

I think you need to get a gauge and fittings or phone a friend that has them to determine what is going.