i bought a new set of headers for my 91z and im terrified to take the old manifolds off and end up snapping one of the bolts then im ****ed. i need tips and advice on what to do that will help getting all the bolts out without snapping any.

 

Soak em all with PB Blaster and let em sit overnight. Then get a good socket/wrench and use steady force. Don't be scared, just lube them up good.

 

But put a socket with short extension on the heads and tap a half dozen times with a hammer, the shock/vibration will help loosen them. keep spray'n blaster as you turn them out......

 

See, I use a long wrench, the box end, so I can watch what the bolt is doing. Usually you can feel if its twisting. Shocking and lube are a MUST too. You can warm the engine up and try to break em loose too. Just gotta let it cool down b4 working unless you have asbestos hands/arms and cant be burnt. Go easy. if you can get it to turn a eighth of an inch, you got it made. Just rock it back and forth. Go easy. You will be fine. More lube!!

-D

 

Yep, good advice above. I try to decide on how much force I'm going to put on the bolt and stay under that while working the other variables and coming back until it breaks free. IMO, gradually increasing to a set tension on it for a while is better than repeatedly exceeding the bolts limit. Make sure the socket is tight fitting as well.
Heat cycling with penetrating fluid in-between (if you can get it to the threads) will help wick it up into where the threads make contact. IMO, the engine may be the best way to expand what's around the bolt vs. heating the bolt up itself. Other than breaking the initial tension, heating the bolt will work the opposite of what you would want to do. Could douse water or penetrating fluid on the bolt to cool it off or even try freeze spray/dry ice on the bolt head while the engine block is still hot. Could use gloves and extensions when working around the engine, I've tightened header bolts that way before. From what I recall stock manifolds act as a spacer between the bolt head to where the threads are so penetrating fluid might be difficult to get to where you need it.
As anything wear safety glasses and use common sense as you are typically near the limits on a lot of things if the bolt is stubborn.

Hammer and slight reverse torquing can help break it free (freeing the corrosion bond).

A lot of people prefer using an impact, but in that case it will either break free or just break.

If it does break off, I've heard a lot of good things about welding a nut on what's left and retrying. Last resort may be to break it off at the head where you can get to it after you remove the manifold. that way you'll have something to work with as well as get to the threads to add penetrating fluid.

IMO patience is the most important part of succeeding. It may take a few cycles of heat/penetrating fluid etc. for it to finally come loose. Hope that helps.

 

thanks everybody! when i put them on in the next week or so ill tell how it goes

 

EVERY day between now and then spray them with pb blaster

 

Despite all my best efforts and decades of experience, I snapped an exhaust bolt off in a head last spring, had to remove the head to drill it out and install a helicoil. When it snapped I mashed my thumb nail so bad I had to drill the nail to release the pressure on it to sleep; what a pain that bolt was.