Ok heres the deal I have experience and the special camshaft holding tools. Someone has worked on the 3.0 L 1991 4runner before. Tthe camshaft bolts are scarred and my impact and or breaker bar will not loosen the bolts, in fact I broke a cam sprocket with the force applied and still no joy. It seems someone put these on with a threadlocking compound and a impact gun? What are my options? Cut the sprockets and bolts and order new? get new camshafts and sprokets? You can feel groves on the camshaft journels and bearing surfaces. BTW this is to replace both head gaskets. This is for a customer Im almost inclined to suggest a replacment engine. Thanks in advance for and help or advice you guys may have. PS im using a newer Snapon 450' lb gun, I have never run into this situation I can not even budge them with a 4 foot breaker bar!

 

Cam retainer bolts? Torch them puppies and gun them again.

 

Id say if your air gun isnt stripping and spinning then try a more torquey gun, whats the worst thing that happens? you strip the heads off then grind them out and replace the sprockets and bolts like you were mentioning beforehand anyway. you could also try the really redneck way of improving your impact wrench. disconect the air ling and get a pipe that fits over the receiver run the hose through the pipe and plug it in. Hit it with the impact gun and when it locks up keep on it and wrench on that bar along with it. I wouldnt recomend this but it was the only way i was able to get a bellhousing bolt free when i was doing the tranny on my mazda pickup last month. Nearly broke all my fingers when it actually did come loose and the impact gun pinned my hand against the trans though...

 

Thanks guys I will try all of your great suggestions, Im so peved that I broke a sprocket already.

 

I have had to use my 4' car jack handle over a 1/2" breaker bar attached to a black color impact socket. While pulling the jack handle I beat the handle with a 6 pound sledge hammer. The beating by the hammer is what broke loose the bolt and NO there was no thread lock on the threads. Look at the back side of the bolt head and notice the very small ring cast into the bolt near the edge. That is what makes the bolt lock so well and so damn difficult to break loose. I put a flat washer between it so next time it will come off much easier. Heat will not work unless there is thread lock on the bolt.

My $0.02....been there, done that

 

I agree with the heat thing, and I think it works regardless of thread lock. The heat shifts the molecules in the metal so it expands and contracts helping to loosen it up. I had to use heat when taking my drive shaft bolts off and I dont think there was any type of seal on them.