Exhaust bolts

[wholberg]

I am trying to remove the muffler and cat from my 87 and am finding that even after soaking bolts for days in PB blaster, every other one is just snapping off. Is this typical? I am ready to just cut/grind off every remaining fastener.

[rwest]

Yes, most people have good luck getting them cherry red with a torch or induction heater and then removing.

Doing them cold will give you a high probability of snapping them off.

[TimT]

Did you use heat? get the nut glowing cherry red.. let it cool a tad and try to back it off

I have pretty good luck dealing with my 911s exhausts...

My Cayman was a total ****ing nightmare...

Header-swap-headache-fml


Broken studs!! Yay all 6

The jigs for the 911 center on the exhaust port... The M96-97 engines have elongated oval ports, where you need a good stud for reference..

Fun times

[mepstein]

MAP gas for 2 minutes and then touch an old candle or a piece of paraffin to the fastener to lube it. Works great. You can get a map gas kit at any home store . You remove a lot of rusty bolts when you live on the east coast...

[wholberg]

I will try heat. I lived most of my life in southern Arizona and I am still not used to this East coast humidity and its effect on stuff like this. Thanks.

[Marc Bixen]

Cut em off and replace them. You'll end up replacing them anyways. When reinstalling, use Porsche high temp silver anti-sieze paste 000-043-305-08, then if you ever need to do it again...

[boyt911sc]

I was skeptical at first how this inductive heaters effectively make the removal of rusted fasteners for exhaust and mufflers easy and convenient. I even contacted RWest to borrow his inductive heater. But a local Pelicanparts member allowed me to use his inductive heaters instead.

See pictures of the rusted nuts and bolts removed without even using penetrating oil. Also able to remove the heat exchangers from the motor without breaking a single exhaust stud.







You got to try this incredible tool to really appreciate it. Not cheap but worth having one. Someday, I will buy one.

Tony

[Ok here we go]

I just used a cut-off wheel on the nut end and punched the through-bolts out. Don't bother wasting your time trying to be cute and saving them - just replace them with new ones. And use anti-seize.

Once you remove the bolts, you will find that your cat will still be attached because it's bonded to the crosspipe by corrosion - insert a heavy-duty screwdriver between the two and hit it with a BFH to free it.

[john walker's workshop]

Slice the nut or bolt head off with oxy/ acetylene if they are rusted undersize wHen no wrench will get a grip.

[burgermeister]

Use SS bolts and silicon bronze nuts and you won't have this problem again. They do need checking and possibly retorqueing after initial install and a heat cycle or two, or you may find some of them self removing.

I use 5/16" fasteners, as I had trouble sourcing the bolts & nuts in metric. Happily, 13mm tools work just fine on 5/16 hardware.

[MichaelSJackson]

When using heat to free up a rust weld, I've found that trying to tighten them, instead of loosening, will provide better results. Heat, tighten just a bit, should hear the rust weld crack and then just loosen them off. Don't know why. Was just good advice handed to me and I'm passing it on.

[911pcars]

Strategy #1:
Heating a nut may expand just enough to either loosen their grip and/or allow penetrating oil to work its way in (Kroil or equiv.).

Don't try the same method with a stud or bolt. If it's hot enough, the bolt thread or shank may distort when applying loosening torque. Use this opportunity to expand the aluminum material around it (expansion rate is greater) to allow penetrating oil or equiv. to wick between the threads. Keep your wits.

Strategy #2:
Use a small Dremel cutoff wheel to slice into stubborn nuts w/o touching the threads. Notice the high temp charring from previous attempts to loosen their grip. Rotating a large blade screw driver in the slot does the trick. A screwdriver with square shank and adj. wrench can apply more separation torque. All studs cleaned, inspected and reused. The three nut and stud assemblies shown conveniently unscrewed from the head:




Strategy #3:
Only destroy material as a last resort and after attempting all removal techniques.
A generous rebuild budget helps ease the stress.

Sherwood