I have horses in Northern California and want a power post driver

[Eric_Phillips]

I just can't get my head around building one with a hydraulic ram, just can't figure out how they free fall. I have used hydraulic impact hammers in the past. But they are a different animal all together!
Hammer & Steel | American Dealer for Junttan Hydraulic Impact Hammers

I have a Shaver driver and they use a single acting cylinder. You connect the pressure side like you would and hydraulic cylinder but the low pressure side has a hose directly to your sump. This way there is very little back pressure on the cylinder when you push the valve.

I would not worry too much about a plate on the top of the posts unless you are wanting the tops to be in pristine condition. I have pounded on some posts that hit rocks and the tops were fine. This is a livestock fence not a million dollar estate privacy fence.

I am in western NY and have my post driver up for sale. Let me know if you are interested. Just noticed the title. Little too far to ship a post driver.