Wheel drive motor on OMC 441 fro but not too ;-)

[Maddy]

Hi guys, well after a bit I ended up rebuilding the perkins 4.108, put it back in and it ran great for 10 mins, the rhs chain drive motor for the wheels lost all forward workings, the funny thing is it would go backwards. What i have figured , the pump is a line of 3 pumps, the one closest the diesel motor runs the right side wheel drive, the middle pump runs the left wheels and the end knobby looking one runs the hydraulic cylinders. The hydraulic drive motor is a swishy type with lots of little pistons, I dont know the correct name sorry, lol. Would it be the pump or drive motor i should be getting fixed as it has reverse but no forward just on that one side ? Many Thanks, You are all awesome and i am lost with out you all.

 

[Maddy]

I have been reading up and maybe its the swash plate in the pump for that motor, what do you think guys, I really need help on this. Please.

 

[Tazza]

I have been reading up and maybe its the swash plate in the pump for that motor, what do you think guys, I really need help on this. Please.

That type of motor is a piston motor.
Your best way to know where the issue is, would be to swap drive motors from side to side. If the issue moved, it's the motor, if it doesn't, the pump is at fault.
Both the motor and the pump will have wear plates that can wear and cause issues, a sheet of glass and wet and dry sand paper will re-flatten it and hopefully restore it.

 

[Maddy]

That type of motor is a piston motor.
Your best way to know where the issue is, would be to swap drive motors from side to side. If the issue moved, it's the motor, if it doesn't, the pump is at fault.
Both the motor and the pump will have wear plates that can wear and cause issues, a sheet of glass and wet and dry sand paper will re-flatten it and hopefully restore it.

Hi Tazza, will do, thanks for that, I will report back when i have tried that

 

[Maddy]

That type of motor is a piston motor.
Your best way to know where the issue is, would be to swap drive motors from side to side. If the issue moved, it's the motor, if it doesn't, the pump is at fault.
Both the motor and the pump will have wear plates that can wear and cause issues, a sheet of glass and wet and dry sand paper will re-flatten it and hopefully restore it.

Hey Tazza, swapped motors and the good motor from the other side does the same, reverse is good, forward is no go. What gets me is how can a rotary piston pump (which i assume it is but not 100% sure) can work one way (reverse) fine and not the other way (forward) . Bloody thing.

 

[Cooee]

Hey Tazza, swapped motors and the good motor from the other side does the same, reverse is good, forward is no go. What gets me is how can a rotary piston pump (which i assume it is but not 100% sure) can work one way (reverse) fine and not the other way (forward) . Bloody thing.

hey there Maddy Are the shafts on top of the transmission pumps fully actuating ...I had a similar situation where the servo rams that turn the pintel shaft on the pump wern't fully extending One of them was bypassing in one direction That caused the shaft not to turn in one direction and hence a similar scenario ... Think I disconnected the servo rams jacked machine off ground and used a big shifter to rotate the pintel arms ....That at least / first told me wether the pump was delivering oil ...My machine sounds to be similar in the pump drive configuration though I'm not sure what actuates the pintel shafts on OMC441 ....If its mechanicaly operated IE : levers and rods you may need to check that the lug mounted to the pintel shaft isn't loose and rotating without actually turning the pump shaft .....when i first got my machine the lugs had been let go loose and flogged the keyway in the shaft I repaired it with that Devcon liquid metal and have had no trouble 15 yrs now ....Hoping its something simple usually is Cheers

 

[Maddy]

hey there Maddy Are the shafts on top of the transmission pumps fully actuating ...I had a similar situation where the servo rams that turn the pintel shaft on the pump wern't fully extending One of them was bypassing in one direction That caused the shaft not to turn in one direction and hence a similar scenario ... Think I disconnected the servo rams jacked machine off ground and used a big shifter to rotate the pintel arms ....That at least / first told me wether the pump was delivering oil ...My machine sounds to be similar in the pump drive configuration though I'm not sure what actuates the pintel shafts on OMC441 ....If its mechanicaly operated IE : levers and rods you may need to check that the lug mounted to the pintel shaft isn't loose and rotating without actually turning the pump shaft .....when i first got my machine the lugs had been let go loose and flogged the keyway in the shaft I repaired it with that Devcon liquid metal and have had no trouble 15 yrs now ....Hoping its something simple usually is Cheers

Hi Coooee, we removed the mechanical links , (the 441 has the little "T: bar control stick to drive it) and we moved the arm on the side of the pump with a big shifting spanner, but I will double check that the arm is correctly turning the shaft, thanks for that, I'll come back with the answer Thanks Maddy

 

[Tazza]

Hi Coooee, we removed the mechanical links , (the 441 has the little "T: bar control stick to drive it) and we moved the arm on the side of the pump with a big shifting spanner, but I will double check that the arm is correctly turning the shaft, thanks for that, I'll come back with the answer Thanks Maddy

Cooee called me today about this, he made a very good point, I have seen wear on the pintle arms cause issue, another possible issue is the relief valves in the pump. Every hose to the motors has a relief valve screwed into the pump. There will be 4, if a spring has broken, you won't get pressure for that direction. So that is another possible thing to look for.
Does yours use the sane pump as Cooee has? a Vickers TA1919? these were used in the Bobcat 743 series.

 

[Cooee]

Cooee called me today about this, he made a very good point, I have seen wear on the pintle arms cause issue, another possible issue is the relief valves in the pump. Every hose to the motors has a relief valve screwed into the pump. There will be 4, if a spring has broken, you won't get pressure for that direction. So that is another possible thing to look for.
Does yours use the sane pump as Cooee has? a Vickers TA1919? these were used in the Bobcat 743 series.

I have 4 relief valves that I took out of my pumps Im sure they were 5000 psi I dropped mine down to 3500s when I put the larger wheel motors in ...there was no issue with them at about 3000 HRS ...If you wish to try them and they are compatible I'M happy to send them to you if it helps to get you going or at the least maybe to fault find . Contact Tazza I'm happy for him to forward you my number or if you prefer Email Add