Exhaust bolts

i want to replace the two bolts with stainless and the three nuts with copper flashed ones. What size are those? Anybody tried it?

They were very tough to undo and the bolts will rust off.

 

Mixing metal types is not a good idea. You will get into what is called galvanic corrosion and it will actually lead to a more severe form of corrosion, especially if you live in an area where there is either salt in the air or they put salt/spray on the roads during the winter months. Sticking with a carbon steel or stainless steel (based on how your exhaust system was fabricated) will be your best bet and then putting some form of say grease or other penetrant on the metal to help fend off the corrosion.

Keep in mind that a minor layer of corrosion is actually a good thing as that prevents further corrosion from happening. This thought is actually done on purpose in most power plants and the like high integrity systems by putting in a known corrosion causer into the system and allowing it to put a thin layer on the metal and then removing the product to let it seal the metal from other corrosion causers.

 

I agree, you're better off leaving that bolt in, unless it's completely damaged. I would just take the nut all the way off, clean it up a bit and put some anti seize lube and away you go.

 

I ordered long brass nuts and stainless bolts. I will reuse the existing bolts and nuts with copper grease and when it's time to drop the subframe and transmission I will make the swap and see how it goes.