AMCClover258, how are you doing with that rear bolt on the valve cover? I just spent several days getting to (and removing) that sucker, so I thought I'd throw my two cents in.
My situation was that I had a local service shop install an aluminum valve cover a few years ago. It recently started leaking oil a lot, and I discovered that all of the bolts were loose (they could be turned by hand). I tried just tightening them down, but it still leaked on the driver side, and I finally figured out that the gasket was broken between the two bolts under the air cleaner. So I decided to do things right; I bought a new gasket and a tube of "The Right Stuff", and resolved to remove the cover and replace the gasket.
Everything was straightforward until I got to that back bolt. I did everything suggested here on the board... I removed the wiper motor, tied the wiring harness back out of the way, etc., then attacked the bolt. Here's the things I tried, in order:
(1) 3/8 drive, 'wobble extension', and a 7/16 socket.
--> This failed right from the start, in that I could not even fit a 3/8 drive between the valve cover and the firewall. The problem is that the firewall sheet metal where the wiper motor mounts bulges out and almost overhangs the top of the valve cover.
(2) 1/4 inch drive, 'wobble extension', and a 7/16 socket.
--> This also failed, the problem being the two brake lines that traverse the firewall right underneath the wiper motor. Using the wobble extension with the socket caused the wobble extension to wedge against brake lines, and kept the socket from getting a 'straight shot' down to the bolt head.
(3) 1/4 inch drive and a 7/16, 12 point, super-shallow wobble socket (
http://www.amazon.com/gp/product/B0021IEBU4/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1).
--> I thought that eliminating the 'wobble extension' from the stack would get the moving parts low enough under the brake lines so they could rotate, but it still didn't work. The extreme angle forced by the firewall bulge kept me from getting a straight enough shot at the bolt to get the wobble socket down onto it.
(4) Here's what finally worked: I put a cutoff blade on my rotary tool and made two cuts about an inch apart on the firewall lip that bulged out over the valve cover bolt. I then got a hammer and iron bar and pounded that 1 inch section back about a quarter inch. That enabled me to finally get the 1/4 inch drive and shallow wobble socket down onto the bolt and unscrew it.
I don't know why this was so much harder on my car than others here on the board have described. Maybe my engine is a little closer to the firewall than most Eagles (or maybe I just lack the finesse that some of the other posters have). Lucky for me, muscles, hammers and iron bars can sometimes make up for a lack of finesse...
I'm now realizing that I'm going to have to unbolt the AC compressor to actually get the valve cover off, but I'm going to save the frustration for another day.
Good luck with your project, and I hope some of this helped,
John Bendiksen