Sunstrand Hydro 90-1136

[groundhog47 347]

Don't know what to do with this unit and tryin' to find how to test it out . Appears from "search" that unit picks up fluid/oil from transaxel. Does motor mount surface exchange as well as pick up fluid/oil from transmission?  Does anyone have a technique  for off transaxel testing unit. I have pictures but not with me now. Any help appreciated!  

Edited February 23, 2013 by groundhog47

[pfrederi 18,597]

The transaxle is the fluid reservoir.  There really isn't a sure fire way to test it with out having it on a tractor.  The real test is to get it fully warmed up and then see how it performs and also run a charge pump pressure test.  You might be able to rig up some external pulley and belt operation to another engine but you would have to have the hydro mounted on a trans axle to provide fluid.

 

For me the bottom line now on sundstrands hydos is they are only worth a parts value unless I can actually see it work when fully warmed up.

[groundhog47 347]

The transaxle is the fluid reservoir.  There really isn't a sure fire way to test it with out having it on a tractor.  The real test is to get it fully warmed up and then see how it performs and also run a charge pump pressure test.  You might be able to rig up some external pulley and belt operation to another engine but you would have to have the hydro mounted on a trans axle to provide fluid.

 

For me the bottom line now on sundstrands hydos is they are only worth a parts value unless I can actually see it work when fully warmed up.

Thanks, I saw inlet ports with the shipping plugs in and could not fig where lines went, then found a pic of one one a tran with filter. You proved my fig correct, guess I bought a pulley for naught.

[coldone 35]

If you have the pump off the tractor, the easiest way to see if its any  good is to take it apart.

[groundhog47 347]

If you have the pump off the tractor, the easiest way to see if its any  good is to take it apart.

It's sposed to be new, so I hate to tear into it but from the last post on storage as long as it has set it might be DOA. All theouter shell has started superficial spotting and surface rust on steel. It turns good and tight on all I've tried. Is the part where tran drive gear sticks out where fluid/oil goes in and out and how does it circulate through a filter (pic shows on opp side)?

If you have the pump off the tractor, the easiest way to see if its any  good is to take it apart.

It's sposed to be new, so I hate to tear into it but from the last post on storage as long as it has set it might be DOA. All theouter shell has started superficial spotting and surface rust on steel. It turns good and tight on all I've tried. Is the part where tran drive gear sticks out where fluid/oil goes in and out and how does it circulate through a filter (pic shows on opp side)?

And oh yes this is not on atractor, it is a bare unit without the selector cam and other stuff.

[pfrederi 18,597]

The filter is on the return circuit.  There is a passage way (part of the transaxle casting) from the motor to the filter.  The pickup (suction line) is protected by a screen and draws into the motor near the bottom then up to the pump.

[groundhog47 347]

The filter is on the return circuit.  There is a passage way (part of the transaxle casting) from the motor to the filter.  The pickup (suction line) is protected by a screen and draws into the motor near the bottom then up to the pump.

Paul, thank you so much, I sorta fig'd that must be the case. I've kinda steered away from hydro due to absolutely no experience. At least feel comfortable to consider lookin' at them for prospect. Guess they just slow fluid circuit to slow down and visa versa. Thanks

[coldone 35]

I was nervous about bad hydros too, but when I found out mine was shot I figured "what the H***". They arent as bad as you think once you get in there. The problems that I have encountered was scored valve plates. 30 minutes to an hour lapping them and I had a working hydro again. 

 

The basics of how it works is that the pump is variable volume, and the motor is fixed volume. Your motion control handle moves the swash plate in the pump. This changes the how the pistons are oriented. Neutral, all the pistons are at the same "height" and no fluid flows. Moving (forward or back) some of the pistons are at the maximum height (sucking fluid from the reservoir) and some are at minimum (pushing the fluid out of the cylinder and forcing into the motor). That is an oversimplified explanation.

 

The manual is very good for tear down and repair. Parts are still available if you need them.

[groundhog47 347]

I was nervous about bad hydros too, but when I found out mine was shot I figured "what the H***". They arent as bad as you think once you get in there. The problems that I have encountered was scored valve plates. 30 minutes to an hour lapping them and I had a working hydro again. 

 

The basics of how it works is that the pump is variable volume, and the motor is fixed volume. Your motion control handle moves the swash plate in the pump. This changes the how the pistons are oriented. Neutral, all the pistons are at the same "height" and no fluid flows. Moving (forward or back) some of the pistons are at the maximum height (sucking fluid from the reservoir) and some are at minimum (pushing the fluid out of the cylinder and forcing into the motor). That is an oversimplified explanation.

 

The manual is very good for tear down and repair. Parts are still available if you need them.

That is a very good expl, figd was like an ac compressor, fixed, so now I understand what that rod does, thaks for the info, someday will get to look at one on a tractor. Most of manuals are vague pics, but still better than nothin'.

[coldone 35]

Here are some vids that might help

 

 

[groundhog47 347]

Here are some vids that might help

 

 

Golly Britt, That's some great video, makes me feel like wrenchin'. Have you put that on instructional on here, Thanks