I am replacing the flex pipe and two mufflers on our 2005 Saab, i.e. everything downstream from the catalytic converter[sup]1[/sup]. I used a Sawzall to cut the flange bolts where the flex pipe connects to the catalytic converter.
The two holes in the flange (for the catalytic converter) now contain the rusted remains of the two bolts. I tried pounding them out using a hammer and punch, but they won’t budge. What should I do? Drill them out? Grind them out? Somehow press them out? Would a torch help?
I guess you could attempt using a screw extractor but if it’s rusted in that much drilling may be the only option. However, if you are in an unheated garage in Ohio right now I assume it’s bitterly cold and maybe a torch will loosen them up. Are you right under the gas tank though? I know guys do this all the time, but lighting yourself on fire is not the best way to warm up in this weather.
I would try and drill them out and then use an extractor. Getting as perfect a center as possible on your drill. Start small. After drilling you may want to get a torch, plumber map gas torch would work and get it very hot and then soak in penetrating oil. I don’t think an extractor would be strong enough if they are seized. If you put the extractor in and it still seems stuck use a small ball peen hammer to light rap on the side of the flange while you are applying pressure. This will often break them loose.
HoneyBadgerDC is right on. The only (minor) thing I would add is to make sure you use oil when you drill out the bolts. It doesn’t have to be cutting oil…even oil from the dipstick will help immensely.
I think you are going to have a hell of a time drilling the pilot hole in the broken bolt from under the car, horizontally…
If you have one, use a center punch to create a dimple, and then use the smallest, sharpest drill bit you have to drill the first hole.
what kind of torch did you use? cause mapp gas or propane isn’t going to do the job. use an oxygen/ acetylene torch set-up with a size 0 to 2 tip & get it glowing cherry red. then use a punch with a pointed tip & a hammer.
you may have to do this more than once. air hammer with a pointed tip works real well too…
I’m kinda concerned about that first picture where it looks like i see a jack stand with air space between it & the car.
i nearly got killed when a car came off a jack (crushed my head between the car & the pavement. they had to sew my ear back on where I’d pulled it almost off from having to pry my head from under the car. the pinch weld of the body of the car was what was keeping it from coming out.)
MAPP gas based torches will work well enough. I’d recommend a combination of PB Blaster sprayed liberally on it and then torching and punching. They will give out eventually.
Perhaps this is not the best way of doing it, but the jack is holding it in the center, and I put safety jacks under the left and right structural members. There’s about a 0.5 inch gap between the the top of each jack and the structural member.
I’ve got a screamer tip (good, hot $75 tip) for my mapp gas torch. i bet it’d take almost a full bottle of mapp gas to maybe work. I’d have those out in a minute start to finish with my oxygen/ acetylene torch.
i do understand though that not everyone has the shop or portable torch kits that i do, but it’s possible he might know a plumber or hvac tech that does.
pb blaster is awesome shit. he’ll want to spray that on the other side of that flange.
Do you have the bolt heads? If they’re marked with radial lines they’ll be made of very hard steel and difficult to drill. If you have to drill follow beowulff’s advice and use a small high quality bit to start with. Try the screw extractors or punching them out every once in a while as the hole gets deeper. If those were the original bolts they may not be marked but they’re likely to be made of some tough metal anyway.
I used to deal with rusted bolts all the time, not on a car but in a car wash setting, on the equipment that needed almost constant maintenance once it aged. Due to the massive amounts of water, we’d get extreme levels of rust on bolts that weren’t stainless (and even then…sometimes, due to acid chemical exposure in car wash soaps).
i don’t see that as an issue. firstly it’s probably the shank of the bolt that’s still in there, so there would be no threads. secondly, it’s not an application that’s super sensitive to a given bolt diameter or design. (I’m not saying not to try & preserve what’s there, just that it’s not going to be a big deal if he has to go to plan B)
You might be right. I like the cut of your jib, soldier. Your username suggests car knowledge, especially about cars that I love, admire and lust after. What’s your story?
This is correct, And I should have been more clear in the OP: there as no threads. Each hole in the flange is just a hole. And the remnants of the bolt (in each hole) is just the smooth part of the bolt. The flanges were originally bolted together using standard bolts and nuts.
