Down pressure lag Ford 7700 w/777 Loader

From time to time I get to operate a Ford 7700 with a 777 loader on it to maintain the driveway on a property my club rents.

It's kind of a pain to use the loader to backdrag gravel because it takes a very long time for it to develop down pressure. The loader responds immediately when raising, and easily lifts a bucket full of pavement millings, but once the bucket has hit the ground it takes 90 seconds to 2 minutes before it will begin to put pressure on the ground and lift the front end of the tractor.

It took so long I initially thought that the valve was set up 1-way.

Nothing moves while I wait for it to develop down pressure. It's not like it's taking up slop in the loader itself or the mounting brackets.

The hydraulic setup is kind of screwy. There's a 2-spool Gresen valve mounted to the loader, which is connected to one of the remotes on the tractor. You bungee the remote lever back and run the loader with the Gresen valve.

For the most part, what you're describing is completely normal. What's not normal is the 2 minute wait time.

Understand that this is a "farm loader" that you're using, not an industrial loader that would have a control valve better suited to avoid the issue you are having. A true industrial type front end loader would have a sophisticated (i.e. expensive) control valve that would include devices like regenerative circuits and backpressure valves to prevent what's called "cylinder voiding". This is simply a cylinder(s) outrunning the pump. In your case, when you drop the loader, gravity does it much faster than the pump can put oil back into the rod ends of the cylinders. By the time the bucket hits the ground, you have these huge voids in the lift cylinders that the pump must fill before it can pull itself together to lift the front end off the ground. Again, what you have going on is very normal for a farm loader.

I have a hard time believing that it's taking upwards of 2 minutes for the pump to catch up, but regardless, you can alleviate the situation by keeping the engine RPMs up. A 7700 has less than a 10GPM pump, so that loader will never be fast anyway.