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Old 05-02-2015, 08:11 PM   #41
djdonis
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Originally Posted by seaniekaye View Post
I am concerned about getting these apart... I need to take this all out to get to my guibo and center bearing. Despite all the praise for pb blaster, I think this could be a disaster.

They look in a very good shape despite all that rust buildup. Use rotary brush to clean them up a bit, soak them, then use impact wrench (find an electric one you could borrow, DeWalt or IR).
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Last edited by djdonis; 05-02-2015 at 08:12 PM.
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Old 05-05-2015, 07:22 AM   #42
timarnold
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Originally Posted by nleeumd View Post
So I am in the process of doing this now (car is on jack stands). I have a e46 330ci. I already sheered off one of the four studs right below the nut. Is it correct to assume that If I 'sheer' off the remaining three studs below the nut, the pipe should seperate from the header flange? Then i should proceed with the drill out method?
It should come apart with no problem after all 4 bolts are off. Heat is your friend and as mentioned if you have it, an induction heater is an excellent way of heating. I was never able to generate enough heat with a MAPP torch. You pretty much have to heat the studs up to cherry red.

Just buy a high quality drill bit (or 2) and do everything you can to get a good flat surface on which to drill.
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Old 08-11-2015, 04:01 PM   #43
Archbid
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At this point in the lifespan of an e46, would it not be safe to say that your original flange bolts are likely gone?

I live in California and have a very well-maintained 330ci. The bolts and nuts were toast. I tried to get one off and it sheared instantly (with overnight PB Blaster).

Best to just not waste time and just get a good exhaust shop to torch them out, replace the gaskets, and start well.
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Old 10-29-2016, 10:23 AM   #44
Streetthispgt
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I recently had to go through the painful experience of drilling out the exhaust studs and just wanted to add to this thread. I decided to go this route as I didn't want to take the chance of an exhaust shop torching / impact hammering them out and potentially ruining the 02 sensors.

If you plan to drill, the easiest way to do this is cut the exhaust studs flush with the manifold so as to minimize the drilling distance. Do not drill all the way through. Drill until there is about 3-5mm of stud remaining at the end and use a round punch with a hammer to tap them out. At this point the stud with the head and whatever material there is remaining should fall out pretty easily. I've had good luck using a 23/64 Chicago latrobe 550 series drill bit (can be bought at grainger) for this job and found cheaper cobalt drill bits purchased at a regular hardware store just weren't up to the task for drilling these hardened studs out. Take your time, it should take about 45min of slow drilling per stud to get them out.

Photo of how the studs should look like after drilling and tapping them out:


Last edited by Streetthispgt; 10-29-2016 at 10:29 AM.
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Old 08-18-2017, 05:21 PM   #45
gde15237
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Originally Posted by Streetthispgt View Post
I recently had to go through the painful experience of drilling out the exhaust studs and just wanted to add to this thread. I decided to go this route as I didn't want to take the chance of an exhaust shop torching / impact hammering them out and potentially ruining the 02 sensors.

If you plan to drill, the easiest way to do this is cut the exhaust studs flush with the manifold so as to minimize the drilling distance. Do not drill all the way through. Drill until there is about 3-5mm of stud remaining at the end and use a round punch with a hammer to tap them out. At this point the stud with the head and whatever material there is remaining should fall out pretty easily. I've had good luck using a 23/64 Chicago latrobe 550 series drill bit (can be bought at grainger) for this job and found cheaper cobalt drill bits purchased at a regular hardware store just weren't up to the task for drilling these hardened studs out. Take your time, it should take about 45min of slow drilling per stud to get them out.

Photo of how the studs should look like after drilling and tapping them out:

I can't see the photos, but this description is exactly what I did. I tried the heating idea for the first one, and it took a lot of time and heat with a propane torch. Once i decided to buy drills from Grainger, I used a 3mm, 5mm and 8.4mm drill in sequence with motor oil lubrication, and it took me maybe an hour under the car to remove the last 3. I used a spring loaded dot punch to mark the center. After drilling to the correct depth, it needed just a couple of sharp taps with a hammer and punch to remove the studs. As a small note, I only needed 1 x 3mm drill, and 1 x 5mm drill, but had to sharpen the 8.4mm drills for the last stud. YMMV............
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Old 08-19-2017, 01:45 AM   #46
steveintheburgh
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scared to death to even start on this mess....
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Old 08-20-2017, 08:58 PM   #47
gde15237
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scared to death to even start on this mess....


Don't fret! Start by lots of presoaking with Aerokroil or similar, and give them a brush with a wire brush.


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Old 07-22-2019, 08:36 PM   #48
lhendrick
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Yeah. So I went under and looked at mine. Cannot see any nuts left at all. They are corroded away to nothing. The studs are now tapered like spikes and no thread is evident anywhere. One of the joints between the joined pipes is open 1/16th inch and obviously leaking. I'm doing this because I need to drop exhaust to get access to driveshaft for a transmission issue, now I'm into hours of drilling for exhaust. This 2002 is rotting away.

Thinking to use the drill out technique with the 23/64 Chicago latrobe 550 series drill bit.

Last edited by lhendrick; 07-22-2019 at 08:52 PM.
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Old 07-24-2019, 08:14 AM   #49
smithpatrick
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froget the drill

Use a dremel with a 1/8" cutting burr ( cutting can be found at hardware store or online, about $15) Slice the nut then pop it with a chisle. they come off with the stud still on the manifold. And do them all this way because you will snap a stud.
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Old 07-25-2019, 04:57 PM   #50
lhendrick
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Edited: Updated: Thanks smithpatrick. There were absolutely no nuts left anyway. Once I got the rust cleared away with a wire brush I could see that the pipe flange is already loose from the header flange and the gasket is gone. There is some loss of material on the mid pipe flange, but it should be OK with cleanup, or a touch of weld fill.

I'll proceed with the transmission work. When done with that I'll drive the open exhaust car to a muffler shop to have the exhaust studs removed with their nuclear tools, and I can rehang the exhaust with bolts and nuts and new gaskets. Hopefully the flanges are not too far gone. ha ha!

Second Edit: Success, the entire exhaust system is off! I unbolted the rear and center mounts and lowered the rear to the floor with a trolley jack and it pulled free from the header with only one tap with a hammer. The studs look useless and will have to come out, but not today.

Thanks for the support.

Updated: I bought some good drill bits and started drilling out the studs. It started well, with the smallest 1/8 inch bit going right through the cut off stud quickly (10 minutes). Then it slowed down. The next size up bit was 3/16 and the tip snapped off, and luckily just flew out of the hole. I found a larger sharp bit and was able to drill out the stud to about 1/4 inch but it took an hour.

I am really looking forward to getting the exhaust system back on and getting out from under the jacked up, jack stand supported car. At age 70, this will be my last under car repair. Life.

Last edited by lhendrick; 08-14-2019 at 06:04 PM.
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Old 08-14-2019, 06:04 PM   #51
lhendrick
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** Final Update: SUCCESS!! ** . I bought some tough bits and most importantly, I got a bench grinder with a stone sharpening wheel and it made all the difference. I watched some Youtube on how to sharpen a bit. Easy! Even with $11 23/64 550 series drill bit from Grainger) I had to sharpen repeatedly. My second stud took 45 minutes, then the last two took only 20-30 mins each with crawling out and sharpening and changing bits. Used a lot of oil to lube. I used a $49 Craftsman 3/8 inch corded drill. Forget about battery drills. Forget 1/2 inch too heavy to hold over your head all day. Got gaskets and exhaust flange supports from FCP too.

This job is done once I put the replacement bolts and nuts in to hang the exhaust system back on. This job started with me replacing the gear selector shaft on my auto trans, and over in another thread I thanked the group there for all the advice. That all started when I replaced my failing gear position sensor and broke the nut and the end of the selector shaft off!

Mounted the exhaust yesterday and road tested today. The flanges on the pipe from the header to the first muffler are blown out pretty bad where the replacement bots go, but with a new stock flange support it is holding together. If I were keeping this old boat or using it everyday I would replace that whole exhaust pipe to get new flanges. As it is I can drive it occasionally or donate it.

Thanks to all for the encouragement.

Last edited by lhendrick; 08-14-2019 at 06:08 PM.
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