Removing Exhaust Manifold/Down Pipe Connection ?

[54blackhornet]

I’ve decided to replace the single exhaust on my 71 GMC. Can I expect the fasteners to break off at the manifold outlet ? I am using plenty of PB Blaster in hopes it will help..thanks

[toolboxchev]

This gets messy, it works 95 percent of the time.

heat with propane torch tip until red, hit with cold water hose.

do this 3 or more time over then let soak in PB Buster.

The cycling action from heat and cold breaks lots of rust loose. You are talking about the 3 manifold studs at the collector, correct?

When you put it back together use brass manifold nuts, new studs in the manifold. The studs that snap off had no hope after that. I replace all the studs with new when doing this.

[maverickmk]

And, make sure the manifold has cooled down before spraying it with the penetrating oil - or

[truckster]

Originally Posted by 54blackhornet

I’ve decided to replace the single exhaust on my 71 GMC. Can I expect the fasteners to break off at the manifold outlet ? I am using plenty of PB Blaster in hopes it will help..thanks

I use heat, I use PB Blaster, I use a long breaker bar with a cheater, and I consider myself lucky if any of the studs don't break. Take your time and go slow and you'll have a better chance.