I have a broken bolt on my exhaust manifold on the drivers side. Just broke for whatever reason. Im assuming its causing one of the exhaust leaks im having on my truck which is a very apparent ticking. Would my best bet be drilling it out or taking the whole manifold off and welding a nut or washer onto the broken bolt. Not currently trying to put headers on just trying to fix my exhaust leak.
Broken rear exhaust manifold bolt
- Thread starter Jjbiskup
- Start date
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Remove manifold, weld nut to remaining bolt. Hopefully, there's still some bolt above the head surface. This may or may not work, but the odds are good. I pulled two broken bolts out of the aluminum head on my Trailblazer the first time I changed the exhaust manifold.
Depending on the manifold, you'll probably want to cram in a pair of manifold spreaders before you loosen the other bolts. Even then, once the manifold comes off, you may find that it's cracked.
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Depending on the manifold, you'll probably want to cram in a pair of manifold spreaders before you loosen the other bolts. Even then, once the manifold comes off, you may find that it's cracked.
Hipster
I'm Awesome
I have not had whole lot of luck with the weld-a-nut method but I have center-punched and drilled them in incremental sizes until I was close to tap size. The heat from drilling, left handed drill bits etc. can pull out the slug. if it's really buggered some machine shops can EDM and helicoil/timesert them if you pull the head.
Instead of attempting to remove the other manifold bolts in hopes of them all coming out without breaking schurkey said, would you think its possible to drill it out with the manifold still on?
Not and leave anything suitable for re-threading and re-use. You won't be drilling "centered", it'll be near-impossible to keep the drill straight 'n' true, and if you're not careful, you'll drill as much out of the head as you do the bolt shank.
I tried that on a BBC motor home 35-ish years ago. Then we sourced a replacement cylinder head.
Maybe you'd have better luck than I did. Motor-home exhaust manifolds get hot enough to glow, so the bolts had been "heat treated" about a thousand times.
I would go into that job with an expectation of 70% chance you'll end-up pulling the head due to multiple broken bolts. If you remove the manifold and get the bolt shank(s) removed, you're ahead of the game.
Only if the stars align over hell freezing over while you're holding your tongue just right.
You're more likely to get off center and drill a bad hole off into the head.
So you’re telling me my chances are that i have to remove the manifold in hopes of the other bolts not breaking and most likely remove the head? If thats true i might just wait until next summer to do it. Its the verryyy last bolt on the right side of the photo. Also is there any tricks to removing the bolts without them snapping other than using heat or working them back and forth.
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Yup.
I would wait.
They're exhaust bolts. They've been heated every time the engine ran. You'll never get penetrating oil all the way down to the threads, at least not until you've gotten the bolt heads turned far enough to leave a gap at the manifold, or broken the head off. I have no faith in "working them back and forth", but I guess other folks do.
"I" would grab the longest-handle 1/2" ratchet I owned, (about 2 feet long) and SLOWLY/CAREFULLY/GRADUALLY apply reverse torque using a six-point swivel socket and supporting the ratchet head with my other hand, while using extremely harsh language. The long handle allows for the control of power not just "more leverage", while the swivel socket prevents side-force on the bolts.
Maybe you get lucky, and all the bolts come out. It's possible. And if they break...they break. Remove or break as many bolts as needed to get the manifold off, then weld nuts onto the broken shanks and try again, or pop the cylinder head off as needed.
It'll be about the same deal at the Y-pipe flange, except you have the option of using penetrating oil and/or an oxy-fuelled torch. (Oxy-Acetylene, Oxy-Propane, Oxy-MAP-Pro.) If you aren't using extra oxygen with the fuel, it won't be hot enough.) My machinist buddy brags up the success he's had removing seized fasteners by "marinading" them in penetrating oil, sometimes over a weekend, sometimes for an entire week. Good luck. All I ever get out of penetrating oil is a spot on the pavement where it drips off. You can try to remove the nuts, but the studs will likely break and then you either buy a new manifold or you spend time with the torch getting the broken stud(s) out of the manifold.
When the Y-pipe goes back on, use BRASS NUTS so they don't corrode to the studs. Some folks suggest stainless nuts, I've never used stainless.
Auto parts stores sell stud-and-brass-nut kits for exactly this purpose. Thread pitch/size varies, be sure to buy the right parts to fit your manifold.
For example:
www.napaonline.com/en/p/NOE6001930
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Luckily the guy who swapped my transmission took those apart already and only broke one of the studs on the Y pipe flanges. Now most likely the manifold is warped. What would i have to do to get it flat again? Or is a machine shop the only option.
Hipster
I'm Awesome
I goes without saying. This is one of those things you basically have one chance. The manifold needs to be out of the way so you can see what you're doing. In my experience when they break it's flush with the head. Try the shortcut and bugger/butcher it up , when you do get the head off, you throw it away.
