Getting a bit discouraged.
I have been working on my own vehicles for 35 years now, and recently bought an old 1992 F150 4WD 300 six as a project vehicle.

Truck runs great, but sat in a field on the edge of the woods for a long time, so I knew dealing with rust, seized bolts would be a problem.

That said, I have replaced the front spring/shock mounts, rear spring shackles, rear upper shock mounts, radius arm mounts, tank straps, exhaust from the cat back, rear bumper, brake master cylinder and power booster, one rear wheel cyliner, various brake lines.... Lots of grinding, sawzall, torching, hammering, and pounding. Tons of new grade 8 bolts and on and on. Been fun so far as I haven't used a lot of my old tools in years.

Then it was time to go under the hood and start replacing some of the basics.

Last night cap, rotor, wires and plugs and air filter were my goal.

Started with the air filter, had to drill the damn bolts out to get it out and replaced with stainless steel 1/4 20's, then moved on to the distributor cap, took one look at it and thought this is going to get ugly, yep the screws were so corroded the first snapped off, I wasn't going to screw around with drills, trying to drill out a 1/8 inch steel screw in aluminum, so I ran out and bought a distributor, popped it in, new cap and rotor, then moved on to the plugs.

Stopped almost immediately. The first I tried was impossible to remove "without breaking it". Half inch drive breaker bar wouldn't budge the damn thing. Now this makes me nervous, I don't want to break a plug off in the head, I have access to another head but just don't want to get that far into it.

So I will clean around the plugs/holes, and saturate with PB blaster and them soak overnight and try again.

I am a huge fan of PB blaster. My question would be, if that doesn't work, do any of you folks know of some miracle method of removing the spark plugs without breaking the damn things.

I don't mind all the work I have to do to the old girl as I really love the Ford 300 six, and have some future planes for it, but right now I just want to get the basics under the hood done, and the only thing that makes me nervous is the breaking a plug off.

 

Try heating the plug with a torch and spray lots of pb blaster well it's hot! Then remove well hot. Just heat the plug not head.

 

You may break the porcelain but you won't break the threads off clean with the hole.

 

Wouldn't want to rephrase that to "you don't think" it won't break the threads off clean with the hole, would you?

NowI have to figure out a way to get the threaded portion of the plug out of the head seeing as it is broken clean off flush.

 

Did you try heating it?!?

 

Dang, I feel for you. I've got a '92 with an I6 as well, and I'm afraid to turn any bolt on the thing. I ran into the same problem with the distributor and wound up having to replace it since the screws snapped. My current nightmare is the bottom starter bolt snapped off flush with the bell housing
while trying to replace the starter. I've worked on plenty of rusty vehicles here in Michigan and this truck by far takes the cake for giving me headaches.

No real advice here, just saying you're not alone.

 

Wow man, I have never seen that happen with a standard plug before.

 

Just drill it out and helicoil it. Or take it to a machine shop

 

1/2 transmission fluid / 1/2 acetone. Waaaay better than PB Blaster

 

OK got the plug change done. Took 2 hours to change my spark plugs.

Plugs 2, 3, 5, 6 came out just the way a plug should.

Plugs 1, 4 broke off clean/flush with the heads.

Here is how I got them out. When number one broke my biggest concern was how to get the porcelain out of the plug hole, figuring this might be an all day job I decided I better put the truck in the garage, low and behold I turn it over, and when it starts I here pop, then a hell of a lot of noise, I knew exactly what happened, the compression of the cylinder did the porcelain removal for me. ( disclaimer) make sure no one is standing near the engine when you turn the key.

Now that I had a nice clean hole to work with I went to the local hardware store and bought a big ***** easy out.

Now came the issue of how the hell do you get something long enough to reach all the way to the easy out to turn it without spending a pile of money for a complete kit. Well it just so happens that it is pretty close to a half inch drive socket, so I took my longest 1/2 inch drive extension turned it upside down and placed it on the easy out. PERFECT FIT!

So now I need a way to turn an upside down socket extension, I put a 1/2 ich to 3/4 inch adapter on it, then out came the 3 foot crescent wrench. Yes I have to pretty big tools from working on heavy equipment. :P

OK, so I have the easy out, a way to turn, and plenty of leverage. The plug threads laugh at me, and say they are happy and don't want to leave. So out comes the torch, heat the threads up ( warning ) gas in the cylinder will burn off the amount may vary. The torch burned off all the crud around the plug and I could actually see a slight space now, so I soaked it with PB again. Put my easy out back in and started to pull, and pull, and pull heard a crack and thought something broke, but then it just started to come out. YEAH!

Number 4 was a bit tougher, I needed a bit of help for this one. Because of the location I couldn't keep the extension straight enough and needed a cheater pipe on the 3 foot wrench, for a total of about 5 feet of leverage.

Same process, heat with torch, cool, PB blaster, then pull on the five foot lever like your life depends on it, while someone holds the it all straight.

Both came out, and much to my amazement the damn easy out was pretty damn strong, I was concerned it would snap off in the head. I figured it didn't matter much if it did, because at this point if the lower half of the plug didn't come out I would be removing the head anyways.

So all in all, it went well.

1) Break em off.

2) Start engine to blow porcelain out.

3) Heat with torch.

4) Let it cool down.

5) Soak with PB and let it sit for 15 minutes or so.

6) Big ***** easy out, 1/2 drive extension, 1/2 inch to 3/4 inch adapter and large crescent wrench and cheater pipe.

7) A friend to help.

8) Check area for ears that may be offended by yelling, swearing, and general grumpiness.

9) Copper never seize on new plugs.