I have a tie down engineering lp7000 acuator/coupler has anyone ever switched it out or put in the replacement actuator? And if so how big of a job was it?

I changed one out on a Easy Loader trailer. Not hard. Worst part was bleeding brakes.

I have a little more trouble shooting to do but I may have to do it. Thats what I'm having trouble with I can't get any fluid to the calipers.

Have you put the new one on? Hook up the lines and fill the reservoir.
The best way to get the fluid through the lines is to use a fluid extractor. You can get a cheap Mityvac at an auto parts store.

You can do it by pumping the actuator and doing one of two things to the bleeder valve but it takes longer.

One plus on the fluid extractor. Had a broken steel tubing line and after replacing pulled fluid through he system at the wheels.
Just be sure and don't let your reservoir run low.