change hydro oil

[jcworks]

Do they have filters on them? If you have filters, all of the oil will drain from the oil filter mounting spud. If not, you have two options. One is to remove and dump the oil or you will need a fluid extractor..

https://www.hydro-gear.com/wp-content/uploads/2023/05/BLN-52441_P25-23.pdf

Yes, they do have the filters. So, draining is just a matter of removing the filter. Thats good.
The instructions from HydroGear website say tighten the filter guard screws to 115 and the top port plugs to 120. I do not have a torque wrench -- I suppose I could buy one if its really necessary to be that exact. $48 at Autozone.....Geesh. Probably cheaper than having it done at a Toro shop.

 

[Rivets]

Many auto parts stores have loaner programs, just return the tool and your deposit is refundEd.

 

[jcworks]

Many auto parts stores have loaner programs, just return the tool and your deposit is refundEd.

Thats a good idea. I know Auto Zone use to have that loaner program as I doubt I'd ever need one again. I have a stupid question; I have never used a torque wrench. I'm 76. Is 120 lbs something a 76 year old can do? Ha.

 

[bertsmobile1]

You do not need to have the bypass valves open to purge
The reason i is done this way is a hydro has 2 parts a pump and a motor
Both need to get the air removed from them.
Having the bypass valve open allows the pump to be purged first so it is not pumping air & oil into the motor unit .
It will take longer to purge without using the by pass .
Even then some times it will take 100 or more cycles to get all the air out
The cylinders in a hydro are blind like a 2 stroke wipper snipper engine so if there is any load then the air in the cylinder will simply compress & decompress rather than flow out into the breather

 

[jcworks]

Do they have filters on them? If you have filters, all of the oil will drain from the oil filter mounting spud. If not, you have two options. One is to remove and dump the oil or you will need a fluid extractor..

https://www.hydro-gear.com/wp-content/uploads/2023/05/BLN-52441_P25-23.pdf

Yes, they have filters. So, ALL the oil will drain from there, thats good. My only remaining thought is the filter guard screws are to be torqued to 115 and the top port plug to 120. If its really necessary to torque to those levels, if I can't manage that level I suppose a cheater pipe would work.

 

[jcworks]

You do not need to have the bypass valves open to purge
The reason i is done this way is a hydro has 2 parts a pump and a motor
Both need to get the air removed from them.
Having the bypass valve open allows the pump to be purged first so it is not pumping air & oil into the motor unit .
It will take longer to purge without using the by pass .
Even then some times it will take 100 or more cycles to get all the air out
The cylinders in a hydro are blind like a 2 stroke wipper snipper engine so if there is any load then the air in the cylinder will simply compress & decompress rather than flow out into the breather

Bert, I'm wondering where does that air go in the purging process? How does it get out?........I assume it eventually goes into what I think is called the expansion tank mounted on the frame of the mower is all I can think of, and then out into the atmosphere. I assume the expansion tank is that plastic reservoir that has oil in it when its cold.

 

[bertsmobile1]

comes out the breather
Go to hydrogear and download the parts diagram
On some you have to fill through the 1/2" breather hole and they are a PIA .

 

[7394]

There are 2 different types of Hydros, Externally vented (w/Expansion tank(s) mounted above the hydro. Which yours sound like you have.

1 thing of critical importance is cleanliness. Do all the external cleaning BEFORE you even begin to loosen a filter.
Any dirt is the enemy.. Remove the protective Oil filter covers & clean all around & above the filter..

 

[Rivets]

Please DO NOT use a cheater pipe when using a torque wrench. Changes the set torque.

 

[7394]

HydroGear website say tighten the filter guard screws to 115 and the top port plugs to 120.

That would be INCH lbs, NOT ft lbs. So converting that = about 10 ft lbs, For Top Port Plug ONLY.

Filter guard screws tighten to only 65 INCH lbs, or 5.4 ft lbs ONLY.

See link below..

Commercial Oil Kit - Hydro-Gear

Hydro-Gear’s Transaxle Oil Service Kits contain everything you need to optimize the performance and extend the life of your machine's transaxles. With oil formulated from high-quality base stocks combined with modern performance additives, you can expect your Hydro-Gear drive systems to continue...

www.hydro-gear.com