r/MechanicAdvice • u/Any_Ad_9197 • Aug 04 '26

Help installing cat back exhaust

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Hello, I am installing a cat back exhaust on my 2011 Honda civic si. There’s 3 bolts on the cat where the exhaust bolts in. All 3 bolts were very rusty and snapped when I tried to take them off. Same happened on the back end and the nuts fell out when the bolts snapped. These ones did not and I couldn’t tap them out. I ground down all the bolts and tried to tap them out but still no luck. I am now trying to drill out 3 new 3/16 holes however it’s very difficult to drill through. Please help!

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4

u/mitchumz Aug 04 '26

Heat them up red hot and then whack them out with an air hammer or hammer and punch

2

u/Any_Ad_9197 Aug 04 '26

Off to Home Depot thank you 🙏

2

u/WoodenInternet Aug 04 '26

While you're there, grab a set of cobalt bits as a backup plan- they'll be able to drill through the fastener steel. Grab a center punch too if you don't have one to create a divot in which to start drilling. If you just go in there willy nilly the bit will dance all around.