Removing exhaust studs without breaking

[level9]

I figured I would share how I removed my exhaust manifold studs without breaking them since this appears to be a big problem on these WD21s. This was on a '90 with original, very nicely rust rotted manifolds and studs.

 

Luckily, I had a lot of prior experience on the pathy destroying bolts with pb blaster failures, heat/shrink failures, breaker bar disasters and snapped bolt heads flying from my impact wrench.. and I wasn't looking for a repeat in this situation.

 

Here's what I did:

 

- soaked with Aerokroil every other day (basically whenever I remembered) for a few weeks. Aerokroil is like PB Blaster, except it actually works. It will cost you 3x as much as a can of PB too but worth it.

 

- used a cordless impact wrench (not my tear-your-arm-off pneumatic) to SHOCK the studs loose. 5 or so gentle, quick pulls on the trigger and verify it's loose. If not loose, continued soaking. All of the studs came out with the nuts except 3 and those nuts came off.

 

- remaining studs I soaked for another week or so with Aerokroil. During that time I would check the studs with a large pair of vice grips - applying FAIR hand pressure to see if it was loose. If not, continued soaking.

 

- when the studs came loose, switched to a small pair of needle nose vice grips and gripped the stud length wise and they came right out!

 

 

If I had to do it again, I would probably NOT soak the rust-welded nuts. Instead, use them for driving the stud with the impact while soaking the stud area between the manifold and the block. Might have saved a little time.

 

good luck!