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cross threaded rear header bolt.....

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Old May 4, 2013 | 06:59 PM
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Default cross threaded rear header bolt.....

I forgot to grab a bolt, i wanted to re-tap the hole and see if that will fix it.. just need to know what size tap to use???? Anyone know? Thanks!
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Old May 4, 2013 | 11:43 PM
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M8 x 1.25... DON"T TAP... chase... tap removes too much material
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Old May 4, 2013 | 11:48 PM
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Originally Posted by Duffster
M8 x 1.25... DON"T TAP... chase... tap removes too much material
I agree with this but depending on how bad the threads are messed up he might have to tap.

Thread chasers work as long as the threads starting out are straight. If the first two or three threads are crossed threaded then the thread chaser will be following them not the good threads.

The benefit of the tap since its tapered is to go deeper into the hole thus aligning the threads correctly when it cuts.
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Old May 5, 2013 | 08:16 AM
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Yes it seems the first threads are messed up i cant get any old or new bolts or ARP studs started... it goes sidways up or down and then starts.
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Old Sep 15, 2013 | 06:04 PM
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Did you ever get this figured out? I am dealing with the same thing. My bolt is sideways. It goes all the way down just fine but never fully tightens as only one edge of the bolt is contacting the flange as the bolt is sideways.
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Old Sep 15, 2013 | 07:18 PM
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yes, i got under the car on a lift and used the correct size tap. being aluminum i went in 1-2 turns backed it out cleaned off the aluminum and kept going until i hit bottom. put in a new bolt and it worked perfectly. hope that helps
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Old Sep 15, 2013 | 08:52 PM
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Was this bolt the rear on on driver side or passenger side. Mine is passenger side rear bolt. What did you use to turn the tap...is there room for a t handle with sliding shaft or did you use a tap socket? Sorry for all the questions but doing all the research now to fix this.
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Old Sep 15, 2013 | 10:05 PM
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Mine was also on the pass side i dont have AC....removed most of it but the condenser. I actually had to start it by hand then used vice grips till i got it in a few threads then i got a socket on it. vice grips i was able to apply pressure to push it in while turning.
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Old Sep 15, 2013 | 10:22 PM
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Yes the AC up top makes it tough to get in there. I will try the vice grip. What method did you use to keep the tap straight while starting it? Right now due to the cross thread my bolt goes in at maybe a 15 degree angle and I don't want to tap it that way as that is why the bolt heads are not clamping flush on my header flange.
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Old Sep 16, 2013 | 07:00 PM
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i was under the car on the trans side and had a friend hold a light in front of the engine and we just did it by eye ball mine was only cross threaded 1/2 to 3/4 of the way in
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