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I replaced my side mufflers, center exhaust and spark plugs years ago (2011 997.2) and seem to have forgotten everything I did.
Fast forward to today and I’m tacking spark plugs and ignition coils. I tried to do it like last time without removing the bumper and managed to shear off nuts/bolts at the cat. I then proceeded to removed the bumper so I can have a better look. Note to everyone. Save yourself the trouble and just remove the bumper. Upon closer inspection and a slight jog of the memory, I think I could have removed the side mufflers without touching the cats. Oh well.
Now onto the main question. What do I do with these sheared nuts/bolts? I’ve read punching them out might work but if drilling is an option I’d rather do that then stress everything unless punching out is really easy. Then what to replace them with. Also, anything else I should tackle since bumper, side mufflers will be out?
I just went through this last week after removing/installing my mufflers for a gundo mod.
It took me 3 days to get out 3 rusted bolts. Knowing what I know now, I would highly recommend just taking the car to a muffler shop and let them deal with it for a couple of hundred bucks, it's back breaking work.
What you first have to do is hit the bolts with PB Blaster and let it settle over night, and do the same every night. If you get very lucky you can then just use a punch and hammer to get them out. However most likely you will have to then drill into the bolts as much as you can while hammer punching them every so often until they come out. I used a combination of a hammer drill and Dremel with a tungsten carbide bit until I drilled far enough into the bolts where they gave in.
I've seen write ups where they used a torch to heat up the flanges and then punch out the studs. I personally did not want to do that because I was afraid bending the flanges and then get into even more trouble.
M8-1.25 30mm stainless steel hex bolts from the auto parts store. They looked better to me than what Home Depot had to offer.
Also if you have access to a Dremel I would highly recommend you use that with a tungsten carbide bit. In the end I think it worked much better than just using a drill. Basically hit it right down the center and go straight through as much as you can. What that did is soften the middle of the bolt and allow it more room to loosen up.
I have an inductive heating tool wrapped up and under the tree for just such a situation next time it happens. The element coils around the bolt or nut and puts a lot of heat just into the fastener, like a torch, but more focused causing the bolt to swell up. The expansion breaks it loose and then makes it easier to remove either when warm or when it cools back down.
Did my exhaust years ago and installed it back with stainless M8 socket cap bolts and copper exhaust lock nuts with copper anti-seize on them. They socket cap bolts are much easier to angle a ball end Allen tool into. The flanged copper lock nuts lock without the normal nylon insert which will melt by the hot exhaust.
Also, whenever working on my cars, unless the fastener is a high-strength one like for engine, trans, seat rail, etc I usually replace any fastener I remove with a stainless one. With my cars, I'm going to be the one taking that fastener out again the next time and hate dealing with rusted / stuck fasteners that turn a 30 minute job into a 3 hour or 3-day one. I have a large organizer full of different length and head stainless fasteners from M3-M12, different flat and lock washers, and nuts (lock, normal, thin, T-nuts, etc).
For all you Mennonites out there and from my own prior mistakes on attempting to remove especially any exhaust related fasteners . I start soaking the bolts with PB Blaster a week before I decide to tackle the job then the day before a little heat with a torch orinductive heating tool and I try to get the nut moving a little ... If not I will blast it more with PB and then use an impact on the low setting not with the intent to necessarily remove the nut but rather to loosen all the rust a bit. Then if no success some heat one more time an F it .....Impact on full and what ever happens happens unless snapping the nut is not an option.
Auto stores in my area use to sell this stuff that smelled like Rub A535 a clear fluid that you put on seized nuts ... The stuff worked like magic on the worst seized nuts ... I used all of mine up went back for more and the guy said that product was pulled due to cancer concerns ?? Stuff was sooo good ...
Last edited by rileyracing1; 11-30-2022 at 11:21 AM.
Auto stores in my area use to sell this stuff that smelled like Rub A535 a clear fluid that you put on seized nuts ... The stuff worked like magic on the worst seized nuts ... I used all of mine up went back for more and the guy said that product was pulled due to cancer concerns ?? Stuff was sooo good ...
EPA hates us car guys having nice things, first banning r22 refrigerant, now this!
EPA hates us car guys having nice things, first banning r22 refrigerant, now this!
Ha, I have a 30 lb canister of R12 for my 928s and a 30 lb canister of R22 for my home HVAC heat pumps. Facebook Marketplace and Craigslist are your friend
Exhaust applications is the only place where I would consider the use of stainless steel fasteners even though they are not free of their own problems. For rusted out fasteners... heat, brute force, and if busted, drill, more brute force is my method of choice.
For non-exhaust applications, stainless steel nuts and bolts are just problems waiting to happen. You drop one of those suckers into the crevice and you can't get it out (or find it) with a magnet. You will invent a few four letter words for stainless steel. My standard operating procedure is ... if I find a stainless steel nut or bolt on the car I am working on (in non-exhaust), i throw it away. The same procedure is used on quick connect squeeze type clamps IF I touch them, I throw them out. I also absolutely hate those Ottinger clamps on coolant hoses.
Those exhaust fasteners are press fit studs as can be seen from the picture posted above, there is a thread somewhere where the poster got them out by using a ball joint breaker to push them out after soaking/heating.
The yellow chromate hardware pictured are usually grade 8 or 9. While very strong those aren't stainless. It will rust again over time. If I could do mine again I would go with 17-4ph stainless bolts. Can take the heat, load and corrosion all day long forever.
The yellow chromate hardware pictured are usually grade 8 or 9. While very strong those aren't stainless. It will rust again over time. If I could do mine again I would go with 17-4ph stainless bolts. Can take the heat, load and corrosion all day long forever.
Ah you are correct, the ones I got are actually 10.9 grade, not stainless. Oh well, in the end I think the biggest problem are the fact that the originals are pressed studs, if they were standard rusted hex bolts I don't think they would be such a big deal to remove.
11-29-2022, 04:52 PM
Spark plugs, exhaust, busted bolt question.
