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Picked up a used borla cat back. Made an initial attempt at removing the bolts that hold the stock muffler pipes to the midpipe. I presoaked the bolts for 2 days - the lower bolt on the passenger side had some movement. The upper bolt snapped off in place - so I've paused before I move ahead...
1) what is the size of the bolts so I can buy four new ones. Hesitant to move ahead without replacements on hand.
2) advice on how to remove the snapped off bolt? It's definitely at an awkward angle and location for access
Last edited by Black_Valkyrie; Oct 26, 2023 at 07:05 PM.
Maybe bring one of your bolts into a hardware store and find new bolt and nut to compare, try new nut on old bolt to verify it’s the proper thread size (fine or coarse)
On the broken bolt, is the head of bolt broken off and threaded section still securing the old cat back pipe to the mid pipe?
Pictures might help to see what exactly you have going on.
I bought a set of 3 really good German made channel lock type pliers called Knipex off Amazon to get out a broken exhaust stud at exhaust manifold on my C5, used a small torch and a candle to touch to the threads to melt and wick wax up into the threads to help lube/loosen the broken bolt.
It took several tries to get it out.
Use the Knipex pliers all the time working on cars and trucks.
Stopped by the dealer. Confirmed the bolts and picked up replacements from an industrial supply shop. The are not grade 5 as other have said in other threads... they are 10.9 .
Still have the issue of extracting the broken off part so that remains a mystery.
Also the gasket is a Walker 31537 for anyone interested.
Also looking for torque spec for the flange bolts and the sway bar if anyone knows that thx
Stopped by the dealer. Confirmed the bolts and picked up replacements from an industrial supply shop. The are not grade 5 as other have said in other threads... they are 10.9 .
Still have the issue of extracting the broken off part so that remains a mystery.
Also the gasket is a Walker 31537 for anyone interested.
Also looking for torque spec for the flange bolts and the sway bar if anyone knows that thx
Thanks for the gasket part number. Looks like I need two of these on my exhaust setup. Did you get these from a local auto parts store or online?
Local parts store - readily available also online. They aren't unique - same for those 4 bolts pick them up from an industrial supply shop. You'll need the bolts. Don't reuse the old ones.
Torque values anyone? Or a shop manual download?
Last edited by Black_Valkyrie; Oct 28, 2023 at 11:54 AM.
Heat is the best tool available to free up most any fastener. That and a good quality penetrating oil (NOT WD40!) like Kroil, PB Blaster, CRC, etc. If possible, try drilling a small hole down thru the center (keyword: CENTER, or as close to it as you can get it to center). Then try a couple of sizes larger drill bit. After youve soaked the broken piece for a couple days, try threading an easy-out into the broken bolt. Dont really twist it hard until youve put the torch onto the piece that the bolt is threaded into. Heat the Hell out of it. Then try twisting on the easy out. Be careful here, because if you break that easy-out off, you'll have an even larger problem. Hope this helps.....
Heat is the best tool available to free up most any fastener. That and a good quality penetrating oil (NOT WD40!) like Kroil, PB Blaster, CRC, etc. If possible, try drilling a small hole down thru the center (keyword: CENTER, or as close to it as you can get it to center). Then try a couple of sizes larger drill bit. After youve soaked the broken piece for a couple days, try threading an easy-out into the broken bolt. Dont really twist it hard until youve put the torch onto the piece that the bolt is threaded into. Heat the Hell out of it. Then try twisting on the easy out. Be careful here, because if you break that easy-out off, you'll have an even larger problem. Hope this helps.....
Thanks however as mentioned earlier already soaked in penetrant. Also as mentioned earlier the angle and location of the bolt makes it impossible to get a drill in there.
yes those are the right values for the sway bar if you torque them wrong you'll get noise. the upper part of the clamp is a bolt, the lower part is a nut, at the point where the sway bar attached to the cradle
Thanks however as mentioned earlier already soaked in penetrant. Also as mentioned earlier the angle and location of the bolt makes it impossible to get a drill in there.
You may have to remove the pipe to properly access or repair it. Heat.....No substitute for it. Penetrating oil, a GOOD penetrating oil (NOT WD-40), is only part of the solution. Heat is your biggest friend on removing broken bolts, especially exhaust bolts.....
cat back exhaust install - broken bolt assistance
