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Rebuilt Hydro wont purge
#1
S
scarface998
S
scarface998
Hello all,
I have a swisher XZT 60 zero turn mower that I bought early last year. It has about 700 hours and the engine runs perfectly. I ran it last year without much trouble but noticed that the right side hydro wasn't performing as well so I decided to rebuild it. I rebuilt it over the last couple of weeks and made sure that there werent any leaks or parts that needed replaced. The filter looked pretty good and is a serious pain to replace in these hydros so i left it. I put it back on the mower and filled it with 15W-50 synthetic mobil one oil. I have been trying to purge it over the past couple of days but have been largely unsuccessful. I have it lifted on jacks and am doing the standard purge procedure of pulling the hydro bypass levers and moving it back and forth and then releasing them and letting the wheels spin but heres where im having the issue. I havent seen an air bubble come out the reservoir the last two times ive tried to purge and the hydro is acting weird so im hoping someone can give me a bit of insight as to what is wrong.
I'm gonna try and explain my problem as well as i can for as little confusion as possible.
The first thing i do is pull the hydro bypass lever to stop the wheel from turning.
After that, while the engine is running at top speed i move the hydro lever back and forth multiple times to try and get air bubbles out.
After doing this several times i turn the bypass lever off and start moving the wheel with the hydro lever.
The first few times i move the hydro lever after releasing the bypass the wheel turns perfectly and hydro works great.
After a few more times it starts to slow and get choppy like its cavitating.
I cannot for the life of me understand why its working great for 30 seconds and the all of a sudden not work almost at all.
Id also like to add that there was no excessive wear on any of the internal parts while rebuilding and everything seemed to work correctly.
also, i have checked multiple times for leaks and have discovered none.
Any help would be appreciated if someone can please help.
If you have any questions ill try my best to answer them.
THANKS!
I have a swisher XZT 60 zero turn mower that I bought early last year. It has about 700 hours and the engine runs perfectly. I ran it last year without much trouble but noticed that the right side hydro wasn't performing as well so I decided to rebuild it. I rebuilt it over the last couple of weeks and made sure that there werent any leaks or parts that needed replaced. The filter looked pretty good and is a serious pain to replace in these hydros so i left it. I put it back on the mower and filled it with 15W-50 synthetic mobil one oil. I have been trying to purge it over the past couple of days but have been largely unsuccessful. I have it lifted on jacks and am doing the standard purge procedure of pulling the hydro bypass levers and moving it back and forth and then releasing them and letting the wheels spin but heres where im having the issue. I havent seen an air bubble come out the reservoir the last two times ive tried to purge and the hydro is acting weird so im hoping someone can give me a bit of insight as to what is wrong.
I'm gonna try and explain my problem as well as i can for as little confusion as possible.
The first thing i do is pull the hydro bypass lever to stop the wheel from turning.
After that, while the engine is running at top speed i move the hydro lever back and forth multiple times to try and get air bubbles out.
After doing this several times i turn the bypass lever off and start moving the wheel with the hydro lever.
The first few times i move the hydro lever after releasing the bypass the wheel turns perfectly and hydro works great.
After a few more times it starts to slow and get choppy like its cavitating.
I cannot for the life of me understand why its working great for 30 seconds and the all of a sudden not work almost at all.
Id also like to add that there was no excessive wear on any of the internal parts while rebuilding and everything seemed to work correctly.
also, i have checked multiple times for leaks and have discovered none.
Any help would be appreciated if someone can please help.
If you have any questions ill try my best to answer them.
THANKS!
#2
B
bertsmobile1
B
bertsmobile1
You purge at LOW speeds, as slow as the engine car turn.
Give that a try.
Some trans take better than 100 cycles to get all the air out.
Give that a try.
Some trans take better than 100 cycles to get all the air out.
#3
I
ILENGINE
I
ILENGINE
Didn't get the charge pump cover turned 180 degrees possibly. Also when you say excessive wear what do you mean. If there is any scratches between the pump and center section or center section and motor portion that you can catch a fingernail in when raked across those surfaces they are toast.
#4
S
scarface998
I'll give that a try, i never considered purging at low speeds. However this poses another question. Inside the very small reservoir is a small rubber seal that suggest that the whole hydro is a closed loop system which means that it cant be open to air. My question is, does that rubber seal need to be in and the hydraulic pump sealed completely before i start the purging process or do i need to leave it open to air to let the air escape? I'm worried that if i try and purge it with the seal in place, it will blow out the seals as the volume inside the pump increases due to the aerated hydraulic fluid.
S
scarface998
You purge at LOW speeds, as slow as the engine car turn.
Give that a try.
Some trans take better than 100 cycles to get all the air out.
I'll give that a try, i never considered purging at low speeds. However this poses another question. Inside the very small reservoir is a small rubber seal that suggest that the whole hydro is a closed loop system which means that it cant be open to air. My question is, does that rubber seal need to be in and the hydraulic pump sealed completely before i start the purging process or do i need to leave it open to air to let the air escape? I'm worried that if i try and purge it with the seal in place, it will blow out the seals as the volume inside the pump increases due to the aerated hydraulic fluid.
#5
S
scarface998
The rebuild was extremely straight forward and there were very few parts that could be put back together incorrectly. I made sure to put back everything the exact same way it came out. The only wear that i saw was just on the actuator not on any of the surfaces or actual pump parts. Everything else seemed very clean and the surfaces also were great.
S
scarface998
Didn't get the charge pump cover turned 180 degrees possibly. Also when you say excessive wear what do you mean. If there is any scratches between the pump and center section or center section and motor portion that you can catch a fingernail in when raked across those surfaces they are toast.
The rebuild was extremely straight forward and there were very few parts that could be put back together incorrectly. I made sure to put back everything the exact same way it came out. The only wear that i saw was just on the actuator not on any of the surfaces or actual pump parts. Everything else seemed very clean and the surfaces also were great.
#6
B
bertsmobile1
The volume inside a sealed container can neither increase nor reduce because it is sealed.
Foamed oil takes up no more space than unfoamed oil & air on top of it.
Pressure inside the box increases & decreases with changes of temperature.
That is plain physics.
Every box is vented somewhere.
The vents are hard to find and the easiest thing to do is to go through the parts list looking for a vent or vent plug.
You always purge anything at slow speeds because the air takes time to get out.
If you purge at high speeds all you do is chop the large aur pocketes up int very small bubbles that creates a foam.
It is exactly the same as an egg beater, used slowly it just mixes the yoke & whites, used quickly and you trap air in there o make them light & fluffy.
B
bertsmobile1
I'll give that a try, i never considered purging at low speeds. However this poses another question. Inside the very small reservoir is a small rubber seal that suggest that the whole hydro is a closed loop system which means that it cant be open to air. My question is, does that rubber seal need to be in and the hydraulic pump sealed completely before i start the purging process or do i need to leave it open to air to let the air escape? I'm worried that if i try and purge it with the seal in place, it will blow out the seals as the volume inside the pump increases due to the aerated hydraulic fluid.
The volume inside a sealed container can neither increase nor reduce because it is sealed.
Foamed oil takes up no more space than unfoamed oil & air on top of it.
Pressure inside the box increases & decreases with changes of temperature.
That is plain physics.
Every box is vented somewhere.
The vents are hard to find and the easiest thing to do is to go through the parts list looking for a vent or vent plug.
You always purge anything at slow speeds because the air takes time to get out.
If you purge at high speeds all you do is chop the large aur pocketes up int very small bubbles that creates a foam.
It is exactly the same as an egg beater, used slowly it just mixes the yoke & whites, used quickly and you trap air in there o make them light & fluffy.
#7
S
scarface998
Okay so I spent the better part of like 2 hours purging it today and it definitely got like 50% better. It seems to be spinning perfectly now with no load, but when I put it back on the ground and tried to give it a test ride it started cavitating again which makes me think there’s still more air in it. Any more ideas or should I just continue purging it like you said? Thanks
S
scarface998
The volume inside a sealed container can neither increase nor reduce because it is sealed.
Foamed oil takes up no more space than unfoamed oil & air on top of it.
Pressure inside the box increases & decreases with changes of temperature.
That is plain physics.
Every box is vented somewhere.
The vents are hard to find and the easiest thing to do is to go through the parts list looking for a vent or vent plug.
You always purge anything at slow speeds because the air takes time to get out.
If you purge at high speeds all you do is chop the large aur pocketes up int very small bubbles that creates a foam.
It is exactly the same as an egg beater, used slowly it just mixes the yoke & whites, used quickly and you trap air in there o make them light & fluffy.
Okay so I spent the better part of like 2 hours purging it today and it definitely got like 50% better. It seems to be spinning perfectly now with no load, but when I put it back on the ground and tried to give it a test ride it started cavitating again which makes me think there’s still more air in it. Any more ideas or should I just continue purging it like you said? Thanks
#8
B
bertsmobile1
B
bertsmobile1
Some take longer than others.
How is the oil level ?
As the air escapes, you need to top up the oil.
A lot easier said than done with the trans in the mower.
The tranny guy showed me how to do it with a power drill, tranny out and that is a lot easier.
And some silly questions, what oil did you put in.
Some oils will foam quite badly which is why most use fully synthetic.
How is the oil level ?
As the air escapes, you need to top up the oil.
A lot easier said than done with the trans in the mower.
The tranny guy showed me how to do it with a power drill, tranny out and that is a lot easier.
And some silly questions, what oil did you put in.
Some oils will foam quite badly which is why most use fully synthetic.
#9
S
scarface998
I've been checking the oil level after every purge session and i have to put more oil in every time so that's good. Its definitely purging, just very slowly. I really expected it to purge faster than this. I made sure it was on a level surface and all so i guess ill just keep doing it. I'm using Mobil 1 advanced fully synthetic 15w-50. Thats what i saw recommended for a lot of other manufacturers. Unfortunately the owners manual for this model swisher doesn't tell you anything about changing, servicing, or purging the hydros so i kinda just have to guess. I imagine that they never really expected people to really be servicing these machines. I appreciate all your help by the way. Its been invaluable.
S
scarface998
Some take longer than others.
How is the oil level ?
As the air escapes, you need to top up the oil.
A lot easier said than done with the trans in the mower.
The tranny guy showed me how to do it with a power drill, tranny out and that is a lot easier.
And some silly questions, what oil did you put in.
Some oils will foam quite badly which is why most use fully synthetic.
I've been checking the oil level after every purge session and i have to put more oil in every time so that's good. Its definitely purging, just very slowly. I really expected it to purge faster than this. I made sure it was on a level surface and all so i guess ill just keep doing it. I'm using Mobil 1 advanced fully synthetic 15w-50. Thats what i saw recommended for a lot of other manufacturers. Unfortunately the owners manual for this model swisher doesn't tell you anything about changing, servicing, or purging the hydros so i kinda just have to guess. I imagine that they never really expected people to really be servicing these machines. I appreciate all your help by the way. Its been invaluable.
#10
I
ILENGINE
After rebuild I start the purge process on the work bench, first by turning the input pulley by hand until I can get the output shaft to start turning, then will put a driver in my cordless drill with a socket on it to put on the nut of the input shaft nut and spin the input until it completes purge at least to work bench standards before reinstalling in the mower and doing the final purge. Never had more than just a couple minutes to bench purge on, so I am wondering if there isn't not right about this tranny causing the purge problems. Or many not a purge problem but something actually wrong internal allowing oil to bypass the normal passages.
I
ILENGINE
Some take longer than others.
How is the oil level ?
As the air escapes, you need to top up the oil.
A lot easier said than done with the trans in the mower.
The tranny guy showed me how to do it with a power drill, tranny out and that is a lot easier.
And some silly questions, what oil did you put in.
Some oils will foam quite badly which is why most use fully synthetic.
After rebuild I start the purge process on the work bench, first by turning the input pulley by hand until I can get the output shaft to start turning, then will put a driver in my cordless drill with a socket on it to put on the nut of the input shaft nut and spin the input until it completes purge at least to work bench standards before reinstalling in the mower and doing the final purge. Never had more than just a couple minutes to bench purge on, so I am wondering if there isn't not right about this tranny causing the purge problems. Or many not a purge problem but something actually wrong internal allowing oil to bypass the normal passages.
#11
S
scarface998
Here's what i've deduced so far,
There is nowhere else on the internet with instructions on how to purge this specific hydro. there's also no instruction on what oil to use or anything honestly. This leads me to believe that this hydro was never meant to be serviced. So i imagine that its taking a long time because it wasn't designed to purge like this. This is definitely more of a "replace" than "repair" kind of brand. The purge is very slowly working and its not making any weird noises or anything. All the important internal parts seemed in pretty good shape to be honest, so i imagine there's just an air pocket somewhere in the hydro still. i guess it'll work its way out eventually.
S
scarface998
After rebuild I start the purge process on the work bench, first by turning the input pulley by hand until I can get the output shaft to start turning, then will put a driver in my cordless drill with a socket on it to put on the nut of the input shaft nut and spin the input until it completes purge at least to work bench standards before reinstalling in the mower and doing the final purge. Never had more than just a couple minutes to bench purge on, so I am wondering if there isn't not right about this tranny causing the purge problems. Or many not a purge problem but something actually wrong internal allowing oil to bypass the normal passages.
Here's what i've deduced so far,
There is nowhere else on the internet with instructions on how to purge this specific hydro. there's also no instruction on what oil to use or anything honestly. This leads me to believe that this hydro was never meant to be serviced. So i imagine that its taking a long time because it wasn't designed to purge like this. This is definitely more of a "replace" than "repair" kind of brand. The purge is very slowly working and its not making any weird noises or anything. All the important internal parts seemed in pretty good shape to be honest, so i imagine there's just an air pocket somewhere in the hydro still. i guess it'll work its way out eventually.
#12
J
jp1961
J
jp1961
F.W.I.W. - I changed the rear end fluid on my Toyota Tundra to synthetic and it caused a perfectly functioning rear end to slip and start making noises (yes the synthetic oil i used did have the limited slip additive).
I drained it and switched to conventional gear oil and it was fine,,,go figure.
I'm not so sure motor oil is the right oil for a hydro unit, either.
Regards
Jeff
I drained it and switched to conventional gear oil and it was fine,,,go figure.
I'm not so sure motor oil is the right oil for a hydro unit, either.
Regards
Jeff
#13
I
ILENGINE
Hydrogear uses 20w50 motor oil and tufftorq uses 5w50 synthetic. I think this guy has the parker drives, which seem to have odd issues, or at least the ones I have seen in the shop. Like when the unit gets hot will pump all the oil out of the drive via the expansion tank. Will actually proceed to dump over 2 quarts of oil out the top of the unit until the drive has no oil left inside.
I
ILENGINE
F.W.I.W. - I changed the rear end fluid on my Toyota Tundra to synthetic and it caused a perfectly functioning rear end to slip and start making noises (yes the synthetic oil i used did have the limited slip additive).
I drained it and switched to conventional gear oil and it was fine,,,go figure.
I'm not so sure motor oil is the right oil for a hydro unit, either.
Regards
Jeff
Hydrogear uses 20w50 motor oil and tufftorq uses 5w50 synthetic. I think this guy has the parker drives, which seem to have odd issues, or at least the ones I have seen in the shop. Like when the unit gets hot will pump all the oil out of the drive via the expansion tank. Will actually proceed to dump over 2 quarts of oil out the top of the unit until the drive has no oil left inside.
#14
S
scarface998
S
scarface998
Alright everyone, I finally got all the air bubbles out and im still having an issue. Now it seems like the right side hydro is slipping. It doesnt seem to want to move when i just use the right wheel but if i add the left wheel to compensate, the right wheel will get up to full speed fine. Is the oil making the clutch slip? they're shouldnt be any reason for it to slip that i know of. When rebuilding the right side the clutch had plenty of material on it. Maybe i havent gotten all the air and i just got enough air out to get it up to speed with some help? will using it continue to purge any leftover air? Let me know what you think.