Question on tapping a rear shock screw

In an effort to remove the screws holding the rear shock bar pin, I of course managed to rip the heads right off. Fortunately, I did this on the driver side where the clearances are better. Now I'm gingerly working the screws in the passenger side with Liquid Wrench and a ratchet.

In an effort to avoid cutting through from the inside I plan to do the following:

a) Center punch and drill the center of the screw out
b) Liquid wrench the bolts yet again and wait a few minutes
c) Work an EZ-out into the screw and see if I can easily remove the bolt, making darn sure not to break off the EZ-out
d) When c) doesn't work, drill and tap the holes
e) Use anti-seize on the new screws

So here are my q's:
1) If the EZ-out DOES work, I will chase the threads to clean out the crap, but what is the screw size: looks to a 5/16 something
2) When the EZ-out doesn't work, what size tap are people using when going the drill/tap route?
3) What screws are they using to replace the old ones? Shank length too?
4) Any tips on drilling/tapping as I've never had to do it before?

I will be using a tap with a T handle and 3 and 1 oil with the tap.

Thnx much

thats the exact same project i'm doing this afternoon too.... i'm just going to drill them out and use stainless 5/16" hardware with nylock nuts..... and yes.. never-seez.... its tight but there is room above the frame bracket to get in there with a wrench.. unless my 99 is different than my 87...
mike

Mine broke 3 of the 4 rear upper shock mount bolts

I tired the esay out, what a waist of time...
I ended up drilling them out and using a larger bolt... I just sucked them down with an impact wrench no need to tap the hole..

Ive had them on there for 3-4years and there still there...

PB blaster and heat Id reccomend to some one before they brake those bolts off...

Perhaps this is naive, but how can you get the nylock nut on the backside without cutting through from the inside? Or are you going to weld the nut in place?

Final Report on busted bolt heads

I finished up my project and just wanted to let people know how it turned out for future reference.

The bolts that go in the rear shock bar pin are 5/16" x 18 hardware. I determined this by gauging the one bolt that I managed to get out.

I chose the most accessible bolt to work out my plan and try different approaches.

First I drilled a starter hole for an EZ-out. Tried the EZ-out then promptly put it away.

Then I started drilling out the hole with the intention of eventully tapping a new hole. I used a small bit to drill through at first, then followed with increasingly larger bits. As it turns out, when I got to the 17/64 bit, I cleared the hole altogether. The remaining shank literally spun up the threaded hole and released on the back side. Then all I had to do was chase the threads with my 5/16 x 18 tap to clean out the rust.

When I used the tap, I used ATF as the lubricant. Got this tip from a Jeep Service tech who has done this many times.

On one of the 3 busted bolts, the shank didn't shoot out the back side of the whole, but I was able to take a punch to make an edge that I could grab onto with some needle nose pliers and twist that little sucker out.

Then I was back in business.

i couldnt get my fat meat cleaver and a wrench in the passenger side bracket, so i made the opening bigger with my grinder