Stainless steel on exhaust components

[old-tank]

A few years and many thousands of miles ago I posted my frustration (shared) with frozen nuts and bolts on exhaust components of my 55.  Tired of impacts, penetrants, heat, dremels, nut splitter, I replaced with stainless steel.  I was soon advised that stainless steel in that environment would fuse solid.  Not so.  All came loose as if new.  So easy that one had fallen out (the reason for messing with it).  The source of the failure was the lock washers from the heat...they were about as useful as flat washers!

[Bhigdog]

I use long length brass nuts with hi temp anti seize. Last ones i removed were in place for at least 20 years. Came right off and were reusable....bob

[Frank DuVal]

At work we have enough trouble with stainless steel bolts galling to stainless steel nuts. Of course it is probably just overtightening them, since they are softer than grade 5 typical hardware.😉

We started buying Moly coated stainless steel nuts to prevent the galling. 

 

I do use stainless steel studs with brass nuts on exhaust systems when I can. I also use lock washers, because I had trouble with the nuts loosening!

 

I'm glad it worked out for you!👍

[Bloo]

In the upfit of new police cars, I have had stainless nuts freeze to stainless bolts while running the nut down, before they ever hit the washers. When removing equipment at the end of the cars life, a majority (but not all) of the stainless bolts just twisted off.

 

I was advised in some other thread that by carefully selecting what grades of stainless to use in the bolts and the nuts, the problem can be avoided. I don't doubt it, but I'll bet it never happens at a hardware store.

 

Anyway, I am also glad it worked out for you.

 

Edited May 27, 2019 by Bloo (see edit history)

[Bloo]

1 hour ago, Frank DuVal said:

I do use stainless steel studs with brass nuts on exhaust systems when I can. I also use lock washers, because I had trouble with the nuts loosening! 

 

You can also use steel nuts on the stainless studs if you need more torque than brass can provide. It works well and doesn't get stuck like stainless does.

[Smartin]

Lack of everyday use definitely contributes to the ease of fastener removal, as well as quality of storage when the car is resting.

[60FlatTop]

I have had three exhaust systems on my '64 Riviera over the past 40 years. I use a nickel based anti-sieze compound on the bolts, balls & Sockets, and slip joints. They come apart easily. I even took one set off and painted them after using them a few years. Painting used exhaust pipes, what some people do.

 

Those pipes lasted another ten years, until the long front pipes perforated at the slip joint of the resonator eliminator pipess. The pipes came right apart. That was over ten years ago, I would expect them to come apart easily next time, as well.

Bernie