Exhaust Manifold Leaks

[94Sport5sp]

Hi: Slowly but surely the problems are being resolved on our truck. The new muffler removed a great deal of sound and now it will be harder for the neighbors to know when the truck is running. At least almost. The exhaust manifold is leaking (noisy) and a new gasket would fix the problem. Trouble is the bolts which hold the manifold on have rusted out heads and the bolts are rusted into the head. The easiest solution would be to find some magic stuff to spray around the manifold to seal the leaks but I do not think that exists. So I have to contemplate how to coax the bolts out. I have a bolt extraction socket. A fluted socket which grabs whatever metal it can and bites into it. I believe that this is twisting the bolts and will break them if I continue to apply pressure. (At least the socket grabs the heads snugly.) Any suggestions? Thanks PaMnd

[Carroll Haines]

I have recently finished removing multiple broken exhaust manifold bolts in my 71 534 LN 900. I tried all manner of potions without any luck. i found that heating with an acetyline torch to cherry red, then gently tapping with a hammer to loosen them works sometimes. If unsuccessful, cut off bolts square and carefully centerpunch and drill with increasing diameter drills until you reach 5/16". Then use a 3/8" coarse thread tap and carefully run the tap into the bolt hole. Mine had soft metal bolts and drilled/tapped easily, except for one that had what I guess was a grade 8 bolt. For this one I had to purchase special solid tungsten carbide drill bits (quite expensive). these worked quite well. If the threads are ruined, they may be repaired with helicoils. Good Luck, It took me about an hour per bolt, after I figured out what I had to do.

[94Sport5sp]

Hi Carroll

Thanks for the reply.

When you heated the bolts I assume you heated the bolt heads. I do not have access to acetyline torch but I believe my neighbour does. I will check with him later this week.

Thanks
PaMnd

[Carroll Haines]

I removed the exhaust manifolds first. Mine had bolts, not studs and I had to twist off the bolts if they wouldn't turn loose. Then I proceeded to "heat and beat" the remaining bolt as it protruded from the head. Good luck, I ended up drilling out most of mine. When I reassemble I would like to use copper gaskets (which I may have to fabricate) and coat the bolts with high temp anti-seize compound.

[Beanscoot]

While I'm not certain about the Super Dupers, Ford engines generally had no exhaust manifold-to-head gaskets when new. Although aftermarket gasket sets always have them, they only need to be used if the sealing surfaces are damaged by rust etc.

It might be good to have the manifolds resurfaced and avoid troublesome gaskets.

I agree that heat is the solution to getting out the broken bolts. I've twisted off a few and regretted that I didn't use heat.