[2billt]

I prefer to use a remote pump jack hosed to bypass the onboard pump, which I believe is just a single pump off the front of crank.
If that's a no-go then drag the boom into alignment while triggering the swing valve levers then taunt line the boom to the loader bucket and draw them together. After on trailer, slack the taunt line and deck the loader/hoe. Repeat as needed.
Again, I prefer a portable pump for this type of issue as I would leave the pump in the loader until not needed again.

 

[2billt]

So you don't have a single pump. Do you have tandem gear driven pumps mounted toward front of engine?
Diesel?

 

[2billt]

There must be many examples online, you-tube surely has some. I don’t have remote pumps anymore that I could show you as I’ve since retired and scaled down. I had a bone yard of scrapped equipment at my disposal so I had cobbled up several pump/engines to fit the need.
I've spent a lot of time in the timber industry. Many of the smaller production timber sites use Skidders or Crawlers, etc. to access some very remote and timber dense areas. I've had to retrieve many a debilitated or dead equipment and trucks from the most precarious of places and positions. It’s nice to have power steering when drag/towing a loaded log truck blocking a single lane landing access on the edge of 1000' drop-offs. A few years ago, I retrieved a dead 8k mini excavator. I used two log splitters to pressure up dual pumps. I didn’t have quite enough flow to rotate the house or drive motors until I got it relocated and closer to level. I also used a 20k excavator that was onsite to help, I could have just yard it out but didn’t want the possibility of tearing apart the mini. That’s the most recent event for me bypassing onboard pumps. Oh, I had my local hydro shops make jack hose adapters to fit the equipment which made life a lot easier. I think the adapters for the mini cost me around $65.

 

[2billt]

I didn't think of it before but the rental yards must have them also.

 

[2billt]

A lot of 3pt hoe attachments use a remote PTO driven hyd pump. Maybe you know someone that has one, it doesn't need to be anything fancy.

 

[2billt]

Engine may just be hydro-locked.
Often times it's very easy to troubleshoot and fix, was the exhaust flapper open to rain? What happened, how did it seize up?