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Weak Left Side

#1

D

dbshelton

I have a 2016 DC Silver Eagle and the left side is weak compared to the right side. I have adjusted everything as best I can but can't tell if it is the Wheel Motor or the Pump. Has anyone ever tried swapping the wheel motors for testing?


#2

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bertsmobile1

Let side is always weaker because of the belt run it is on the"push" side of the engine pulley .
Add to that the left hydro always seems to get dirtier than the right
So the pulley slips more thus the pump is turning slower & the oil is running hotter thus the left side seem weaker.


#3

D

dbshelton

All that seems to make sense but there is a significant difference between right and left. BTW, reverse seems very close to the same on both sides.


#4

D

dbshelton

Is there a tag or number on the wheel motor so I can see if I can get a seal kit ? I have a seal kit for the pump.


#5

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hlw49

Is your belt tight this can cause this problem. Tighten the nut on the spring bolt to were the spring is compressed to 3 inches. Also the idler arm should run parallel to the frame. If the belt has been loose and slipping it could wear the belt down and bottom out in the pulley then a tight belt won't pull. You might replace the belt and adjust according to what I stated. You can slide the engine to get the proper adjustments. Then you would need to readjust the engine to deck belt. Compress spring to 3 inches like the drive belt. Does the wheel motor feel kinda jerky when you push hard on the steering lever kinda like a quiver.


#6

H

hlw49

dbshelton said:
Is there a tag or number on the wheel motor so I can see if I can get a seal kit ? I have a seal kit for the pump.
Click to expand...
There should be. Use to give a break down of the wheel motor but since they switch to parker the don't seem to have anymore.


#7

D

dbshelton

hlw49 said:
Is your belt tight this can cause this problem. Tighten the nut on the spring bolt to were the spring is compressed to 3 inches. Also the idler arm should run parallel to the frame. If the belt has been loose and slipping it could wear the belt down and bottom out in the pulley then a tight belt won't pull. You might replace the belt and adjust according to what I stated. You can slide the engine to get the proper adjustments. Then you would need to readjust the engine to deck belt. Compress spring to 3 inches like the drive belt. Does the wheel motor feel kinda jerky when you push hard on the steering lever kinda like a quiver.
Click to expand...
It operates smooth, just doesn't have the same power/speed the right side has. I have adjusted everything but I do have a new belt. i will try that next.


#8

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bertsmobile1

You got the answer back in reply # 2
It is a function of trying to drive 2 pulleys that have variable loads from a single belt which is a disgusting thing to do from an engineering point of view
The engine spins clockwise when viewed from above thus the RIGHT side gets a direct pull from the engine then the belt goes to the Left side
Because both the left & right pulleys are applying a load to the belt they cause the tension in the belt between them to reduce
Thus the grip on the left pulley is less than the grip on the right pulley so the left slips, particularly when a heavy load is applied quickly,
Dixies set up looks nice and symetrical to the engineering ignorant but to a person who understands belt drives it is trash.
I have not worked on a DC drives yet so I am not familiar with the belt tensioning .
If both left & right idlers are adjustable then tighten the left one to increase the grip on the left pulley.

Manufacturers who do have engineers working for them overcome this by routing the belt so the left pulley has a much larger contact radius than the right .
They also put a spring loaded tensioner in the left side of the belt run to take up slack in the belt that happens from pulley & belt wear plus belt loading while running.

IF you search the entire forum foe "weak Left Drive" you will find it is about the most common ZTR problem.


#9

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dbshelton

Hard for me to believe but it does make sense. I will have to look at it hard and see what I can do with it.
Thanks for the info guys.


#10

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bertsmobile1

If you have a rolling strain gauge and measure the belt tension between each section of the belt run with the engine running and both hydros under load you would see it is highest between the engine & the right , then a bit lower between the the right & left then a lot lower between the left & the engine.
This is why the fan belt on your car will occasionally squeal when you start the engine and the alternator is applying a heavy load to the belt .


#11

D

dbshelton

See if i am thinking right. Looks like the tension adjustment pulley is in between the engine and the left pump. Maybe crank more tension in or if there is enough adjustment available, use a slightly longer belt for more belt wrap on the left pump?


#12

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bertsmobile1

Give it a tighten
You would be amazed just how little wear on a belt or pulley can make the belt quite slack


#13

D

dbshelton

Is there a good solution to this problem?


#14

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hlw49

If the wheel motors are smooth then you may have a pump problem. Does it make w whining sound from the left pump? It doesn't have to whine but they will if bad enough. Only true way to tell is to do a pressure and gpm flow test. If a Silver Eagle has a seal problem in the wheel motor it will leak out side around the axle seal. If it leaks there don't try to put a seal in it it will just blow it back out again. It is the seals inside that leak and push the axle seal out.


#15

D

dbshelton

No whining sound from the pump. No leaks at all. No heat gain. It does sometimes make a little clicking sound when I change direction. I am pretty sure that is from the wheel motor. Removed the belt adjustment assembly to check everything. The arm was slightly tweaked so I straightened it. Idlers, pulleys look to have no wear. I will also pull the brake drum/hub to see if all is well there and put it all back with a new belt.


#16

D

dbshelton

Installed new belts, new tension adjustment springs, and readjusted belts, lever linkage again. Still slow on the left side. I really don't feel that anything is slipping. Mowed heavily for 2 1/2 hours. It did get even a little weaker as I was finishing. Still smooth with no jerking. I am leaning towards the pump. I have a reseal kit for the pump so I may go that route.


#17

H

hlw49

Seals won't help that problem The seal are to seal it from leaking outside the pump. If it is weak it has wear inside and is leaking past the cylinder block that holds the pistons and the end cap. inside the pump it's self. Seals will not help this you would have to replace the cylinder block and end cap.


#18

D

dbshelton

So there are no seals on the pistons or anywhere else inside the pump?


#19

H

hlw49

The wheel motor on the Silver Eagle does not have pistons in it like the ZT units do. It is a radial axle wheel motor. It has cylinders inside a rotor that drives the motor. The mating surfaces inside a pump must be smooth and without groves in then that would let hydraulic oil escape between the two surfaces instead of being forced into the wheel motor through hoses like the Silver Eagle or channels like the ZT units. If a pump is scrawling it is the oil escaping between the two mating surfaces of the cylinder block and the end cap.


#20

H

hlw49

dbshelton said:
So there are no seals on the pistons or anywhere else inside the pump?
Click to expand...
No no seals inside the pump. You have two seals in this type pump one on the input shaft and one on the trunnion shaft. This the shaft the control arm goes on. There are some o'rings on the check valves and the relief valve.
The one you open so you can push it.


#21

H

hlw49

Hydraulic Oil Booster & Stop Leak - Lucas Oil Might give this a try. Have you adjusted the tracking. Air the tires up to proper level. Front tires to 15 psi and rear to 10 psi. Find a flat level place push both control arms all the way forward and hold in this position and see how it tracks. If it goes tracks to the left slow down the right side and if it goes to the right low down the left side. There are adjusting bolts on the control arms at the pivot points under the seat. Try that first.​



#22

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birdman53

bertsmobile1 said:
If you have a rolling strain gauge and measure the belt tension between each section of the belt run with the engine running and both hydros under load you would see it is highest between the engine & the right , then a bit lower between the the right & left then a lot lower between the left & the engine.
This is why the fan belt on your car will occasionally squeal when you start the engine and the alternator is applying a heavy load to the belt .
Click to expand...
I have a 07 silver eagle and the same weak left side. It make a cavitation noise when climbing a grade but the left pump/motor/ belt? is a lot slower on level grade. Has gotten worse even with a new belt change???


#23

B

bertsmobile1

birdman53 said:
I have a 07 silver eagle and the same weak left side. It make a cavitation noise when climbing a grade but the left pump/motor/ belt? is a lot slower on level grade. Has gotten worse even with a new belt change???
Click to expand...
If it is making the hydro growl then it is deceased.
A couple of options
1) buy and fit a new unit
2) buy and fit the drop in rebuild kit
3) drain & refill with heavier oil to get you through this season then pick between 1 & 2 above .


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