I have to replace a leaky muffler on my 1998 Toyota 4Runner so I went with the Walker Quiet-Flow which is made from grade 409 stainless. It's supposed to be a step up from the cheap-o aluminized steel that most replacement mufflers are made out of. Without paying too much attention, I ordered these stainless M10x1.25 nuts and studs off eBay (the grade is not mentioned): shorturl.at/eCGU6
However, being the OCD BITOG member that I am, I did more research into material grades and now I'm concerned that maybe I didn't get the right grade of bolts. Reason being that stainless steel may gall over time due to the high heat and dissimilar metals. Should I have gotten grade 8.8 steel flanged bolts instead? Or would simply applying copper antiseize rated for 1800 F be enough to keep the threads happy long term? The OEM bolting on the catalytic converter end appears to be steel and with some heat + lubricant I'm hoping it will come out nicely. The bolting on the tailpipe end has seized on with rust and I'll likely have to cut it off.
I am also curious why all the exhaust bolting kits (from Fel-Pro or Dorman for this vehicle) are a double ended stud style, whereas the OEM uses a steel flanged bolt on the catalytic converter end. With the doubled ended stud, you have to remove the nut, then remove the stud with vice grips if it's seized on which could be a huge pain. With a flanged bolt, you could just remove it in one go. I'm guessing with a stud you strain the threads much less during torquing such that it might be easier to remove later?
However, being the OCD BITOG member that I am, I did more research into material grades and now I'm concerned that maybe I didn't get the right grade of bolts. Reason being that stainless steel may gall over time due to the high heat and dissimilar metals. Should I have gotten grade 8.8 steel flanged bolts instead? Or would simply applying copper antiseize rated for 1800 F be enough to keep the threads happy long term? The OEM bolting on the catalytic converter end appears to be steel and with some heat + lubricant I'm hoping it will come out nicely. The bolting on the tailpipe end has seized on with rust and I'll likely have to cut it off.
I am also curious why all the exhaust bolting kits (from Fel-Pro or Dorman for this vehicle) are a double ended stud style, whereas the OEM uses a steel flanged bolt on the catalytic converter end. With the doubled ended stud, you have to remove the nut, then remove the stud with vice grips if it's seized on which could be a huge pain. With a flanged bolt, you could just remove it in one go. I'm guessing with a stud you strain the threads much less during torquing such that it might be easier to remove later?