Rusted exhaust header bolts - my take
10-23-2021, 01:16 PM
#1
Racer
Thread Starter
Rusted exhaust header bolts - my take
Needed to remove exhaust headers so I decided to spend a little bit of time to think about a secure way to remove those bolts. Here's my solution that worked quite nicely.
Tools: Milwaukee stubby impact wrench and Makita impact torque driver
Chemicals: CRC Rust off and CRC Rost Flash Pro
1. Applied CRC Rust off and let that soak about 2-3 hours
2. Applied Rost Flash and then used Makita to "shake" the bolt
3. Applied Rost Flash again and then again Makita to shake the bolt
4. Applied Rost Flash third time but now used Milwaukee with that fourth torque setting that has that arrow that goes around
Result - took only a couple of minutes each and didn't have any issues.
The reason why I used that Makita and Milwaukee with that fourth setting is that I wanted to open those bolts using repetitive "light" impacts and not so much about strong torque which can cause that bolt to snap.
Tools: Milwaukee stubby impact wrench and Makita impact torque driver
Chemicals: CRC Rust off and CRC Rost Flash Pro
1. Applied CRC Rust off and let that soak about 2-3 hours
2. Applied Rost Flash and then used Makita to "shake" the bolt
3. Applied Rost Flash again and then again Makita to shake the bolt
4. Applied Rost Flash third time but now used Milwaukee with that fourth torque setting that has that arrow that goes around
Result - took only a couple of minutes each and didn't have any issues.
The reason why I used that Makita and Milwaukee with that fourth setting is that I wanted to open those bolts using repetitive "light" impacts and not so much about strong torque which can cause that bolt to snap.
Last edited by P9C; 10-23-2021 at 01:44 PM.
The following 8 users liked this post by P9C:
Billup (10-25-2021),
C2-996 (11-01-2021),
DSC800 (10-30-2021),
hardtailer (10-23-2021),
Mike Murphy (10-23-2021),
and 3 others liked this post.
10-23-2021, 06:21 PM
#2
My compliments on your strategy. When I had the heads off my M96, I broke half the header studs on either side. Was able to weld a nut on what remained of the stud sticking out of the head an turn out all but one of the broken studs. The last one broke just below the head surface so I had to drill it out, but luckily I center drilled it accurately and using the appropriate drill sizes was literally able to peel out the threads of the broken stud like wire. Those studs are diabolical.
10-23-2021, 09:55 PM
#3
Rennlist Member
What is bolt of choice for replacement?
10-23-2021, 11:16 PM
#4
Rennlist Member
Needed to remove exhaust headers so I decided to spend a little bit of time to think about a secure way to remove those bolts. Here's my solution that worked quite nicely.
Tools: Milwaukee stubby impact wrench and Makita impact torque driver
Chemicals: CRC Rust off and CRC Rost Flash Pro
1. Applied CRC Rust off and let that soak about 2-3 hours
2. Applied Rost Flash and then used Makita to "shake" the bolt
3. Applied Rost Flash again and then again Makita to shake the bolt
4. Applied Rost Flash third time but now used Milwaukee with that fourth torque setting that has that arrow that goes around
Result - took only a couple of minutes each and didn't have any issues.
The reason why I used that Makita and Milwaukee with that fourth setting is that I wanted to open those bolts using repetitive "light" impacts and not so much about strong torque which can cause that bolt to snap.
Tools: Milwaukee stubby impact wrench and Makita impact torque driver
Chemicals: CRC Rust off and CRC Rost Flash Pro
1. Applied CRC Rust off and let that soak about 2-3 hours
2. Applied Rost Flash and then used Makita to "shake" the bolt
3. Applied Rost Flash again and then again Makita to shake the bolt
4. Applied Rost Flash third time but now used Milwaukee with that fourth torque setting that has that arrow that goes around
Result - took only a couple of minutes each and didn't have any issues.
The reason why I used that Makita and Milwaukee with that fourth setting is that I wanted to open those bolts using repetitive "light" impacts and not so much about strong torque which can cause that bolt to snap.
Hey, if it worked you clearly did the right thing - nice job...
10-24-2021, 12:06 PM
#5
Racer
Thread Starter
This is only a temp setup so I went to a local hardware store and bought stainless steel M8x25mm bolts (3€ pack of 6) + washers. I need to update at some point the whole exhaust system so we'll see then what would be the final solution.
10-24-2021, 03:08 PM
#6
https://rennlist.com/forums/996-foru...l#post16957268
And a real world experience post that followed (not on these cars though):
https://rennlist.com/forums/996-foru...l#post16967804
The following users liked this post:
P9C (10-24-2021)
10-24-2021, 03:18 PM
#7
Rennlist Member
Plain steel also reacts with aluminum... Stainless is better in my experience. Also use generous amounts of high heat (copper) anti seize...
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10-24-2021, 03:29 PM
#8
But Zinc doesn't (minimally anyway) corrode aluminum. Their galvanic index is only 0.2 apart. Zinc is what is plated onto steel hardware. Is it even possible to buy pure steel uncoated hardware and why would anyone want to?
That said, I'm not criticizing any choice. I know what I've chosen, but to the internet, that's just a random opinion. But it is something to maybe think about or look into when changing hardware materials.
EDIT: Antiseize for the win in any case!!
That said, I'm not criticizing any choice. I know what I've chosen, but to the internet, that's just a random opinion. But it is something to maybe think about or look into when changing hardware materials.
EDIT: Antiseize for the win in any case!!
The following users liked this post:
peterp (10-25-2021)
10-24-2021, 06:06 PM
#9
Rennlist Member
I have been recommending this technique for years. I use a low torque MakIta Battery Impact ( 500 in/lbs) with a high Impacts per min (3000)
It's the vibration that does the trick. I don't even bother soaking them usually. ( but I live in the non-rusty South) . The vibration heats up the connection ( by exciting the molecules), and with aluminum expanding faster than steel, the connection turns loose after some vibration time.
For a more maintenance free joint, use coated steel studs with copper anti-size and solid copper nuts. Then just leave the studs in indefinitely..
It's the vibration that does the trick. I don't even bother soaking them usually. ( but I live in the non-rusty South) . The vibration heats up the connection ( by exciting the molecules), and with aluminum expanding faster than steel, the connection turns loose after some vibration time.
For a more maintenance free joint, use coated steel studs with copper anti-size and solid copper nuts. Then just leave the studs in indefinitely..
10-24-2021, 07:16 PM
#10
Racer
Thread Starter
Speaking as some random keyboard warrior that you don't know, long term, you might think about the risk of galvanic corrosion of the aluminum block due to using stainless steel.
https://rennlist.com/forums/996-foru...l#post16957268
And a real world experience post that followed (not on these cars though):
https://rennlist.com/forums/996-foru...l#post16967804
https://rennlist.com/forums/996-foru...l#post16957268
And a real world experience post that followed (not on these cars though):
https://rennlist.com/forums/996-foru...l#post16967804
Last edited by P9C; 10-24-2021 at 07:32 PM.
10-25-2021, 06:52 AM
#11
Racer
Thread Starter
Any recommendations for best possible anti-seize for aluminium alloys that would also be available for purchase globally - some products (eg. Permatex) have a little limited availability over this side of the pond.
There are a few alu-based anti-seizes available but how about this one:
Yep, again a CRC product but the specs are promising:
CRC Ceramic Paste Pro
http://www.crcind.com/crc/CRCproduct...JNwTu_XUEnPg--
Or this one : https://www.henkel-adhesives.com/fi/...e_lb_8009.html
Availability might be an issue in that case.
There are a few alu-based anti-seizes available but how about this one:
Yep, again a CRC product but the specs are promising:
CRC Ceramic Paste Pro
http://www.crcind.com/crc/CRCproduct...JNwTu_XUEnPg--
Or this one : https://www.henkel-adhesives.com/fi/...e_lb_8009.html
Availability might be an issue in that case.
Last edited by P9C; 10-25-2021 at 07:44 AM.
10-30-2021, 08:19 PM
#12
Rennlist Member
Any advice for also using heat? I was thinking if I had to do this I'd soak the bolts as much as possible (being they are in the car upside down) and then driving it up to temperature before immediately applying the low torque impact driver.
I have been recommending this technique for years. I use a low torque MakIta Battery Impact ( 500 in/lbs) with a high Impacts per min (3000)
It's the vibration that does the trick. I don't even bother soaking them usually. ( but I live in the non-rusty South) . The vibration heats up the connection ( by exciting the molecules), and with aluminum expanding faster than steel, the connection turns loose after some vibration time.
For a more maintenance free joint, use coated steel studs with copper anti-size and solid copper nuts. Then just leave the studs in indefinitely..
It's the vibration that does the trick. I don't even bother soaking them usually. ( but I live in the non-rusty South) . The vibration heats up the connection ( by exciting the molecules), and with aluminum expanding faster than steel, the connection turns loose after some vibration time.
For a more maintenance free joint, use coated steel studs with copper anti-size and solid copper nuts. Then just leave the studs in indefinitely..