Tossing in the towell. Now what? (pics )

[TheCoalMiner]

I'm so mad right now.. Glad the wife is at work. lol.
So i recently bought a 2005 john deere ct322.
It came with a bush hog that USE to be a boom mower. ( Alamo )
When I bought it.. the original owner said "oohh yea it cuts great " yet I noticed both the ends of the case drain were plugged. I thought to myself at 1st glance.. Not for long and Just after he showed me it worked.. He hit reverse on the PTO and the case of the pump had a catastrophic failure lol. Ive seen similar set ups like this before and the case drains every time it stops. There has to be a relief valve for the case.
So I got 2k off the machine. lol.
So i took it home and pulled the pump off the mower deck and took it to a local shop for repair. they called me and said no dice.. not repairable and i should come in and look at it.. it literally exploded inside the case..
I paid 2880 thinking it cheaper then a new hog so hell with it.. New pump and I'm rolling. I waited almost a month for the pump to come in. But once it did.. I mounted it and it ran great..It got dark so I just took a run up and back on the father in laws property. 5-8 minutes of run time..
So today I go and hook it up again. Ran great then stopped running entirely.
so i raised the boom and locked it to get out and see what was going on I bumped the pto getting out and boom it exploded. Unreal.
I know I reversed the flow into the case causing it to fail. But im wondering.
How can I stop that from happening? Like a check valve not allowing pressure to backflow?
its a 1 inch JIC. Here's pics.

1st case

the one that exploded today......

you can see i ran a 1 inch line from the case drain.. i needed a check to stop the flow of fluid from going back into the pump case.

https://photobucket.com/u/dague2007/p/bcc38f2d-74ec-44c0-b69f-8388934cfe48
https://photobucket.com/u/dague2007/p/d4843e0b-0c27-4afe-b036-53fbee220e6e
https://photobucket.com/u/dague2007/p/3c6aa1a1-9dbc-42c9-a3a4-c12b57c35707
https://photobucket.com/u/dague2007/p/fd783db8-bb9b-4afb-88d9-93ecced2cc1a

 

[Tazza]

Sadly i can't see the images in my work computer, it's far too old to allow me to load them with photobucket for some reason, but whatever.
I'm wondering if the issue with the motors blowing up is as you said, no relief. When you have a spinning cutter going round and round, then you instantly stop or try to reverse the direction of the blade, you will get a stupidly high pressure spike that can't go anywhere and locks the motor up and will shear the shaft or internals of the motor off.
People have installed a relief valve between the in and out hydraulic lines, case drain lines go back to the tank to allow for some oil cooling.
Oil in ============= Motor
Relief ||
Oil out ============ Motor
Sadly my drawing abilities in text form is limited. THe idea of this setuo will make it so if you have it spinning at full speed and shut the aux hydraulics off, the oil can still travel in a loop Through the motor, across the relief, then back to the motor in a loop till it stops on it's own. Not ideal, but it seems to save motors.

 

[flyerdan]

Sadly i can't see the images in my work computer, it's far too old to allow me to load them with photobucket for some reason, but whatever.
I'm wondering if the issue with the motors blowing up is as you said, no relief. When you have a spinning cutter going round and round, then you instantly stop or try to reverse the direction of the blade, you will get a stupidly high pressure spike that can't go anywhere and locks the motor up and will shear the shaft or internals of the motor off.
People have installed a relief valve between the in and out hydraulic lines, case drain lines go back to the tank to allow for some oil cooling.
Oil in ============= Motor
Relief ||
Oil out ============ Motor
Sadly my drawing abilities in text form is limited. THe idea of this setuo will make it so if you have it spinning at full speed and shut the aux hydraulics off, the oil can still travel in a loop Through the motor, across the relief, then back to the motor in a loop till it stops on it's own. Not ideal, but it seems to save motors.

I sorted the images and kept the original links, as photobucket has a nasty habit of jiggery-pokery with hosting.
Tazza has it right, the best and easiest protection circuit would be to tie the two motor hoses together with a check valve that allows flow from the return line to the pressure line. That would serve as an overrun clutch, so to speak, and protect against reversing it. The fluid should follow the path of least resistance and looping through the check valve is far easier than grenading the motor case.

 

[Lowe.Buuck]

"you can see i ran a 1 inch line from the case drain.. i needed a check to stop the flow of fluid from going back into the pump case."
From the last picture, it looks like you connected the case drain to a tee in the "Return" hydraulic line. Case drains are designed to be plumbed directly back to the hydraulic tank.
In your case that "Return" Line is the pressure line when you reverse the flow. When that occurs, you are forcing 3000 psi fluid in to a motor passage that is not designed to contain anything more than very low pressure.
You either need to plumb a proper drain line to the tank or as suggested, add check valve with a low cracking pressure at the tee to prevent pressurized oil from entering the case drain on the motor.
Note with the check valve installed, you can run the motor in reverse, however the case drain will functionally be capped off (no case drain functionality).