Rusty exhaust bolts
 

I'm changing the head on a 79 GMC truck. The exhaust bolts are very
deteriorated. They are a grade something. Can I buy the matching grade or a
higher grade to replace them. Are all, say, Grade 5 or 8 bolts the same and
usuable for the exhaust? I will be rebuilding this engine later this year and
want to avoid problems later.
Thanks all. Rojo

On Sat, 8 Jan 2005, Rojo2G wrote:

> I'm changing the head on a 79 GMC truck. The exhaust bolts are very
> deteriorated. They are a grade something.

Originally probably grade 2.

> Can I buy the matching grade or a higher grade to replace them. Are all,
> say, Grade 5 or 8 bolts the same and usuable for the exhaust?

Yes and yes. You can even buy stainless steel bolts and studs, and brass
nuts, and never again have a problem with hardware deterioration.

Daniel J. Stern wrote:
> On Sat, 8 Jan 2005, Rojo2G wrote:
>
> > I'm changing the head on a 79 GMC truck. The exhaust bolts are very
> > deteriorated. They are a grade something.
>
> Originally probably grade 2.
>
> > Can I buy the matching grade or a higher grade to replace them. Are
all,
> > say, Grade 5 or 8 bolts the same and usuable for the exhaust?
>
> Yes and yes. You can even buy stainless steel bolts and studs, and
brass
> nuts, and never again have a problem with hardware deterioration.

The higher grade bolts give you greater strength and not neccesarily
better corrosion protection. Your best bet is stainless, but under the
environmental condtions of the exhaust system, even stainless can
corrode over time, but not nearly to the extent of regular steel.

>even stainless can corrode over time
Will there be a problem with threading into an old cast iron exhaust? I guess
I'm thinking like steel and aluminum joining problem.
Thanks

On Sat, 9 Jan 2005, Rojo2G wrote:

> > stainless

> Will there be a problem with threading into an old cast iron exhaust? I
> guess I'm thinking like steel and aluminum joining problem. Thanks

No, there'll be no such problems.

Rojo2G wrote:

>>even stainless can corrode over time
>
> Will there be a problem with threading into an old cast iron exhaust? I guess
> I'm thinking like steel and aluminum joining problem.
> Thanks

retap or run a die over all old threads, as appropriate, and use
anti-seize paste on reassembly.

nate

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