Seized exhaust manifold to Y pipe bolts help (1 Viewer)

[Cattledog]

Hey guy's I could use some help...

The 1996 Lx has 187000 miles. The exhaust needs to be replaced. I have a hole 1/8 inch hole in the seam of the 2nd cat converter.

Here is the issue... The studs from the cast manifold to y pipe are seized. I have hit them with creaping oil for about 2 weeks and tried an electric impact wrench and a 2 foot breaker bar. I have tried tightening them and then loosen them. The studs are not moving. I open to any suggestion. I would really like to avoid pulling the cast manifold from the head. It will add a lot of time to the job and with my luck one of the manifold to head studs would strip..

On the side, I will be replacing the OEM system with the Bosal system from rockauto. I have the system here and it looks OK, but not as good as the original system by a long shot.

Thanks for the help.

 

[fj4068]

Sprayed threads with penetrant while still hot to help draw it into the threads?
Phosphoric acid/rust dissolvant?

 

[Pin_Head]

Cut or grind the nuts off, chase threads and replace with new nuts and antisieze.

 

[Kernal]

How would you cut or split the nuts in that location? IDK

 

[Pin_Head]

If you can get a wrench on them, you should be able to get a die grinder, dremel or OA torch on them too.

 

[Rwhat]

If you can get a wrench on them, you should be able to get a die grinder, dremel or OA torch on them too.

I would try the torch. I use map gas with good results.

 

[Shinichi]

It sucks, but cut the pipes and take the manifolds off. I messed around doing what you are doing and terminally wrecked the studs. Once I had the manifolds off, and attempted to remove the studs, they broke off and I ended up replacing the manifolds(ouch!).

It is nearly impossible to do any real work on those studs with the manifolds still attached to the motor.

 

[Cattledog]

Thanks for all the suggestions. I was able to remove the bolts.

I bought some of the CRC freeze off spray on the off chance it might work for $5. I came in from the passanger side wheel. A couple of hits with the spray and the nuts came off without the impact wrench. I was really surprised.

 

[NKP Garage]

If you ever have them get stuck, strip, or snap off the best thing to do is remove the manifold and soak it down good with PB Blaster or some type of penetrating fluid. Then take a hammer and give the stud a few good smacks. Give the manifold itself (right around the stud) a few good smacks with your hammer as well to help break up as much stuck rust as possible. Then either double nut the stud and try to remove it that way, or use a very large set of vice grips and try to remove it that way. It sometimes helps to loosen/tighten/loosen/tighten a little at a time to help break it loose enough to where it comes out easier. Take your time with it and it will eventually come out. The worst thing that can happen is having the stud get stuck in the manifold and not come out. At that point you would need to drill it out and tap for either 1 size larger threads, or use a rethread kit to put 10x1.25 threads back into the manifold.