Just had my manifolds replaced with the BD Diesel hearing good repour only to be told by the service manager where I bought the truck when I called about the shoddy way they repaired my manifolds 2 yrs ago that due to the stainless bolts being so tuff that they pull the threads of the heads ! Have I screwed my self by doing this???
Just to clarify, this is the same shop that did your manifolds 2 years ago?
Why would they have used "stainless"? The problem is with bolts breaking, not corrosion. Or, did they use some tougher grade of hardware, like grade 10.9?
Given the obvious stress that is causing a bolt, threaded into soft aluminum, to be stretched to its breaking point, the idea that a "tech" would have thought a tougher bolt to be the solution is odd. I'd much rather the bolt break than the other possibilities.
Regardless, maybe they can use a helicoil?
Because otherwise, it's going to suck removing those heads to either replace them, or try to drill/tap to the next size up screw. And, hope both the heads and manifolds have enough meat around the screw holes that they can be drilled for the bigger screws, without intersecting the coolant passage.
I've done quite a few of these broken exhaust screw repairs. The best and most long lasting solution seems to be, Paint the mating surface with a thin coat of dykem or Krylon, then sand the mating surfaces flat until the paint is gone. Reinstall with stock hardware.
Some guys swear by the Remflex gaskets, and they probably do help, but I've not heard of a belt sanded (used, OEM, heat cycled) manifold having this issue repeat. Not even with cheap Dorman gaskets and hardware.