Champion 2650 model 5900705 hydro drive system problems

[Bearsworld]

Hello everyone, I am new to this forum.
I have a Simplicity 2650 zero turn model 5900705 I purchased used.
It had a slight issue with the left side drive when I purchased it and it had horrible looking fluid in the hydro drive fluid reservoir which I knew needed to be changed along with the filter.
I purchased the correct parts and fluid, drained the entire system. Refilled to the correct level but do Not know how to purge the system of air and now left side drive is completely inoperable.
The mower is in fantastic shape. Engine runs great and has a little over 600hrs on it.
I have searched everywhere for a shop manual or online discussion or video on how to purge the drive system of air with NO luck.
I would like some advice/help/directions to 1st bleed the system of air, then check for adjustments and then repair advice ( where to start )
I have looked at what a new pump and new drive motor costs and that is more than I paid for the entire mower.
I know it’s fixable, but I do not want to throw over $1k in new parts in it if I can bleed the air out, adjust something or purchase a seal kit or rebuild kit and fix it myself.
I am mechanically inclined so I’m not afraid of doing the repairs I just have No knowledge as to where to start other than I know I need to bleed the system of air 1st.
Thank you in advance for your advice/guidance on this issue.

 

[Rivets]

This is how I do it and I warn you this may take some time. Minimum of two hours unless you get real lucky.

1. Block both front wheels so the unit can’t roll forward.
2. Jack up the rear end and put on jack stands so the wheels are at least 2” off the floor.
3. Start up the unit, run just above idle and push the sticks forward about halfway and hold for 30 seconds.
4. Bring sticks back to neutral and let it run there for 30 seconds.
5. Pull back on the sticks about halfway and hold for 30 seconds.
6. Bring sticks back to neutral and let it run there for 30 seconds.
7. Repeat steps 3-6 a half dozen times.
8. Shut off unit and let it sit for 15-20 minutes.

During these steps the wheels should be turning slowly, but may turn faster as you go through each cycle. I have had units which the wheels don’t start turning until the fifth or sixth cycle.

9. Repeat steps 3-8, but this time move sticks to full travel and hold for 1 minute.

If you are lucky your wheels should be turning much faster. If they do not turn faster repeat step 9. Now is when you need patience. Why? Depending on how much air is in the system, you may have to going through the steps 5-10 times before you get all the air out. It will be helpful if you have an assistant who can put his foot on the wheels to see if he can stop the wheels from turning. I’ve had a couple of units I’ve had to let the unit sit over night and repeat the steps the next day, because I couldn’t get it to push out all the air.

10. Now that your wheels are turning fast and you can’t stop them, cycle 6 times through left and right turns at all speeds.

If everything looks good, drop the unit off the stands and test the unit.

REMINDER: KEEP YOUR EYES ON THE FLUID RESERVOIR OR FLUID HEIGHT, AS YOU MAY HAVE TO ADD EACH TIME YOU SHUT THE UNIT OFF. LOW FLUID WILL RESULT IN POOR OPERATION. AS YOU REMOVE AIR WHO NEED TO REPLACE WITH FLUID.

There are other ways to do this, depending on your equipment, but this is how I do it. Also, not uncommon for one pump having more air than the other, so you must keep checking both each time.

Forgot to ask; did you use the fluid recommended by the manufacturer? If not, this could add to the problem.

Good Luck, have PATIENCE.

 

[ILENGINE]

Jack the tires up off the ground. Pull the bypass rods/rods to free rolls. Start the engine and run at idle and then move the direction control levers slowly from forwards and backwards several times .. Then push in the bypas free roll levers and do the same backwards and forwards motions several times. And then put the tires down and see if it will move correctly. Sometimes you have to do this several times to get the air purged.

 

[Bearsworld]

This is how I do it and I warn you this may take some time. Minimum of two hours unless you get real lucky.

1. Block both front wheels so the unit can’t roll forward.
2. Jack up the rear end and put on jack stands so the wheels are at least 2” off the floor.
3. Start up the unit, run just above idle and push the sticks forward about halfway and hold for 30 seconds.
4. Bring sticks back to neutral and let it run there for 30 seconds.
5. Pull back on the sticks about halfway and hold for 30 seconds.
6. Bring sticks back to neutral and let it run there for 30 seconds.
7. Repeat steps 3-6 a half dozen times.
8. Shut off unit and let it sit for 15-20 minutes.

During these steps the wheels should be turning slowly, but may turn faster as you go through each cycle. I have had units which the wheels don’t start turning until the fifth or sixth cycle.

9. Repeat steps 3-8, but this time move sticks to full travel and hold for 1 minute.

If you are lucky your wheels should be turning much faster. If they do not turn faster repeat step 9. Now is when you need patience. Why? Depending on how much air is in the system, you may have to going through the steps 5-10 times before you get all the air out. It will be helpful if you have an assistant who can put his foot on the wheels to see if he can stop the wheels from turning. I’ve had a couple of units I’ve had to let the unit sit over night and repeat the steps the next day, because I couldn’t get it to push out all the air.

10. Now that your wheels are turning fast and you can’t stop them, cycle 6 times through left and right turns at all speeds.

If everything looks good, drop the unit off the stands and test the unit.

REMINDER: KEEP YOUR EYES ON THE FLUID RESERVOIR OR FLUID HEIGHT, AS YOU MAY HAVE TO ADD EACH TIME YOU SHUT THE UNIT OFF. LOW FLUID WILL RESULT IN POOR OPERATION. AS YOU REMOVE AIR WHO NEED TO REPLACE WITH FLUID.

There are other ways to do this, depending on your equipment, but this is how I do it. Also, not uncommon for one pump having more air than the other, so you must keep checking both each time.

Forgot to ask; did you use the fluid recommended by the manufacturer? If not, this could add to the problem.

Good Luck, have PATIENCE.

Thank you Rivets for replying to my thread
Yes it has 20/50 synthetic oil in it as per manufacturers recommendations.
I will try the purge method more. There are the 2 bypass bolts ( one on each pump ) to allow the mower to be pushed while not running, do I have to open them up to purge the air or does it simply vent back into the tank?

 

[Bearsworld]

Jack the tires up off the ground. Pull the bypass rods/rods to free rolls. Start the engine and run at idle and then move the direction control levers slowly from forwards and backwards several times .. Then push in the bypas free roll levers and do the same backwards and forwards motions several times. And then put the tires down and see if it will move correctly. Sometimes you have to do this several times to get the air purged.

Ilengine Thank you for replying to my thread.
This unit does not have bypass rods. It has a bolt on each fluid pump that has to be backed off 2 turns in order to move the mower by hand without it running.
I do not know if they have to be opened as part of the purging process so I did ask this question in my reply to “ Rivet “

 

[ILENGINE]

Ilengine Thank you for replying to my thread.
This unit does not have bypass rods. It has a bolt on each fluid pump that has to be backed off 2 turns in order to move the mower by hand without it running.
I do not know if they have to be opened as part of the purging process so I did ask this question in my reply to “ Rivet “

Yes they have to be opened to purge the system. they have the same effect as the bypass rods. they are bypass valves which open a passage from the pump into the pump housing whereas the bypass rods on a single self contained unit lift the drive motor off of its base which allows the fluid from the pump to escape.

 

[StarTech]

 

[bertsmobile1]

Rivets forgot to put the pull the bypass rod bit in that ILLengine corrected.
Happens when we do it all the time
The bypass diverts the oil from the pump so it does not go through the motor
So you bleed the pump first during which time the wheels should not turn, but they might very slowly due to friction then you bleed the motor .
After you have gone through Steps 1 to 8 in Rivets reply, close the bypass valve let the mower sit then go back to 1 again .
The oil can froth which is why you have the engine turning slowly

 

[Rivets]

Sorry, old age catching up n me.