ok. i just traded my truck for a 92 mustang. the problem im having is getting the stock hu out. what you need is two of these "tools" to stick into the four holes, and then push them towards each other and pull out. Then the hu is supposed to just slide out. The actual problem is that i dont have this tool. ive been using coat hangers and really whatever else i can find. I just cant get the stupid thing out!
Okay, you need to push outwards with whatever you use (smaller screwdrivers that fit the hole work well). The best thing to do, if your dash won't get damaged, is to wedge in two fairly large flathead screwdrivers on either side, push outwards, and pull out.
the best way is to take some coathanger wire and cut it into about 6 or 8 inches then bend it into a u shape stickit into the holes as far as you can then apply outward pressure on the wire and slowly pull out headunit dont pull to fast or the wire comes out i used to have a mustang thats how i did it
this method works perfectly its been done many times before i used to do installs for a living its safer than using a screwdriver thats how inexperienced hacks do it