Broken exhaust manifold bolt

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BOSS

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Came across this write up online for removing broken off exhaust manifold bolts. I guess you know what's about to go on in my garage :)


Credit to Chevyboy86 for posting this:
Chevyboy86 said:
this is advice for all the guys in here with head and manifold issues, i used too work in a machine shop for 4 years...just a jobber shop whatever came thru the door pretty much...it was all old conventional machine tools, my boss was an older scottsman been machining for 40+years. i have taken ALOOOOT of broken studs, dowels, bolts out. shaved heads, exhaust manifolds. tons of engine machine work and re-work and re-machine, i.e. shaving heads exhaust manifolds, honing, port and polish jobs, boring...all different types of stuff.

im gonna go on a limb here cuz their is alot of questions asked in this thread.

1.the "fastest" way too get broken studs out is too weld a nut of bolt too them, if they are above the surface...BUT if you are working with aluminum...this can really create problems, sometimes the heat tends too bind the materials together even tighter resulting in pulling the threads out with the stud when it comes or "mashing" them up. the "safest" way too get the threads out (and i realize you cant sometims do this cuz you still got the motor or part still on the truck or you dont got the tooling) is too grind the broken peice flat if you can, center punch it as close too the middle as possible, just start with a ***** punch and you can move it around. once you are satisfied take a center punch and givver a good wack. then start drilling, start with a small drill first (pilot hole) just too make sure of your depth if its a blind hole. then if you have access too a left hand twist drill they work exceptional, most of the time uhoh.gif . if that doesnt work, go until you are at the tap drill size in steps, by this time you should be able too see the crests of the female thread. take a tap, i like too use a "starter spiral machine tap" cuz they arent as brittle, and the spiral flute design really helps you pull the threads out one at a time. once you are done the thread is usually like new unless it was stuck in the first place because some other yahoo before ****ed it up already. thats the way i prefer, especially if its a newer part, and its off of some dudes hot rod than im really carefull with it. i tend too stay away from easy-outs, they can be a nightmare. they are made of a type of high speed steel, they like too break. once you break one off in a hole its a real chore too get them out. usually gotta drill them out with carbide. seems like a lengthy process but its the safest way of doing it welding is fast but its risky...if you got the part out a machine shop should be able too do it for you in no time. alot faster than watching a mechanic doing a machinist job rolleyes.gif (gonna get chewed for that one haha).

2. warped heads or exhaust mani's - again no matter what, ive seen heads come off that were farely new and they were out about .005" - .010". its not a big deal for a machinist too take a little skim off a head for you. old ones ive seen just completely screwed too no return. exhaust manifolds are the same most of the time they are out so much its not even worth it. just buy new ones but its worth bringin them down too a local machine shop too see how bad they really are. cuz if they arent bad it might only take an hour max too take a little skim cut or as one guy said get it surface ground. it all depends on how cheap you are HAHAHAHA.

bringing your parts into a machine shop isnt gonna hurt your wallet by any means its worth a try, they might be able too fix something for you that would have taken hours and write a new curse word bible in a couple minutes with no fuss and a cheap fix. just for all you guys imput. just make sure you get a written estimate!!!!!!!!


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Apparently it's a big problem, I never knew.

[yt]0yG6WlBNZGI[/yt]


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hoe

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You never knew? lol. My lq9 has 2 on driver side and 1 on passenger. NO codes. quite, and I run the piss out of it. I plan to leave the manifolds and do wye pipe back to tail with 3" pipe.

---------- Post added at 12:41 AM ---------- Previous post was at 12:38 AM ----------

The 5.3 I pulled to replace had 1 broke on each side for a total of 2. Still was quite as shit, no codes.
 
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BOSS

BOSS

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Here's a great writeup on welding and extraction strategies, if you don't have a welder you can certainly take this printout to the shop and ask them to follow it!


The Art of Extraction

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BOSS

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Posted by someone, somewhere:

someone said:
My battle is over. I win. I FINALLY got the bolt out today using the carbide 3/16 bit. I cannot believe how easy it drilled into the stud; almost like a hot knife through butter. I then used an easy-out to unscrew it. The headers are on and she's runnin strong right now!

In conclusion:

The broken bolts that were sticking out had about a quarter inch of stud left and I welded an oversized nut to them. They came out very easy. Make sure you use a large, oversized nut so the weld can bond on the most real estate.

The stud that was broken flush was even a worse pain due to its location against the firewall. After removing the firewall heat shield to gain room, I utilized a $130 right-angle air drill and a solid carbide bit ($22). I tried several times to to weld a nut onto the top of the bolt but it was unsuccessful. The carbide bit won it![

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dorisk

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Good you made this a sticky, know many Tahoe owners who had problems with this.
 

rick from minnesota

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broken exhaust manifold bots

in regards to broken of exhaust manifold bolts or/leaky exhaust, i'm not by any means a professional but somewhat mechanical and another solution to the problem which isn't as time consuming or invasive yet very effective is "The Original KAP" from www.kralautoparts.com . this bracket just simply bolts on and puts just the right supplemental pressure where its needed on the manifold and yet still allows for the expansion and contraction needed which is why the factory bolts and even replacement bolts have/will continue to sheer off. highly recommended i've done one on my suburban and going to help my neighbor next week with one on his van. good luck with your results you should be nothing less than satisfied. hope this reaches many of you with theses problems as it applies to many vehicles, Tahoe,Yukon, Silverados, cargo vans, Denali, Escalades, ect.
 

meadows.harrison

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I just took my exhaust manifold off and found a broken bolt for nr.7 cyl. Going to chuck it up in a bridgeport to extract
 

yukon702

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Another thing is you shouldn't be taking out exhaust bolts without prelubing them with some sort of penetrating lubricant. Ive sprayed them while they are hot for a few days just to be on the safe side before i actually take off the headers. And also if you spray them while they are hot don't inhale that shit.
 

jsoltren

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Yep. Seems to happen to lots of LQ4 and LQ9 engines. The factory bolts are crap. I would go ahead and replace them preemptively before you need to weld them out. Does anyone have a good go-to replacement? If it were me I'd select a stainless steel part.

So I'm surprised you're seeing this on a newer engine?
 

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