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Broken studs in exhaust manifold
Posted by: Tre107 ()
Date: February 18, 2018 07:55AM

The studs that connect the manifold to the exhaust pipe snapped and I was wonder what the best way to get them out would be. They were almost rusted through so I knew they would snap. I know I could drill it out and re tap it but I don’t want to break a bunch of drill bits. How should I get these studs out?

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Re: Broken studs in exhaust manifold
Posted by: MattNall ()
Date: February 18, 2018 08:18AM







MODERATOR
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Re: Broken studs in exhaust manifold
Posted by: Caraholic4life ()
Date: February 18, 2018 08:21AM

I have seen people heat the manifold around the stud using a torch and successfully removing the stud with a pair of vise grips. I have also seen this method fail.

Another avenue as you mentioned, would be to drill out the old stud and tap new threads. To do that, I would suggest cutting the stud close to the manifold and file it flat, center punch the center and make an initial hole with a smaller drill bit, (maybe a 1/4" bit) then move up to the proper size for the tap.
Be careful and slow. Don't hurry as that is more likely when problems occur.

Once you successfully get the old studs removed, I would strongly suggest installing Stainless Steel studs and use Brass Nuts. Do not under any circumstances use Stainless Nuts on Stainless Studs as that simply won't work out well.

Another option would be to buy a set already done by someone else.

An option some may use with varying success and failure would be to drill out the studs and run a smaller size bolt through the not tapped hole with a nut.
Personally I would not advise this method as I feel it could result in broken "Ears" on the manifold.

1962 95 F.C. Van
1965 Monza Coupe
Westminster, Maryland

MID ENG enthusiast &
prior Kelmark owner.



Edited 1 time(s). Last edit at 02/18/2018 08:22AM by Caraholic4life.

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Re: Broken studs in exhaust manifold
Posted by: Tre107 ()
Date: February 18, 2018 08:29AM

One of the studs I already tried drilling but my harbor freight drill bit just snapped off in the hole.

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Re: Broken studs in exhaust manifold
Posted by: MattNall ()
Date: February 18, 2018 08:38AM

Get better drill bits and keep drilling now. Otherwise Dave will sell you good manifolds.





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Broken studs in exhaust manifold
Posted by: Tre107 ()
Date: February 18, 2018 08:46AM

Ok I’ll see if I get some new bits tonight thanks for your help

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Re: Broken studs in exhaust manifold
Date: February 18, 2018 09:07AM

Use Left Hand drill bits. They turn CCW so the force may also unscrew the broken stud.
Heat and a bit of paraffin to begin, for sure.
I've had 'em come out while drilling...


Dan Davis ~ Pierce County, WA ~ CORSA Western Director + Corvairs NW + North Cascades Corvairs + Corvanatics
1966 Corsa Turbo coupe ~ ~ 1966 140 Corsa ~ ~ 1965 Monza 140/4 'Vert Sierra Tan/Fawn ~ 1964 Monza 'Vert (SOLD) ~ 1960 Monza Ermine White/Red PG ++ ~ 1965 Monza 140/4 Evening Orchid w/ ivory/black interior ~ 1962 Monza Wagon 102/4 ~ 1963 Rampside/Scamper ~ 1963 Red/Greenbrier ~ 1969 Ultra Van #468

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Re: Broken studs in exhaust manifold
Posted by: davemotohead ()
Date: February 18, 2018 09:15AM

I did a vid on drilling them out as well, sometimes its harder than others, this is a hard one, it takes patience some times, and Matt it right, I do have exhaust logs with new studs for sale.







Email me at: Dave Motohead

1960 4dr sedan caveman car
1961 Rampside (Chetside)
1962 Rampside (Barnside)
1962 Short Rampside (Shortside)
1962 Monza 700 Wagon
1963 Monza 900 coup (General Nader)

-----------------------------------
Rust Free Lancaster Ca

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Re: Broken studs in exhaust manifold
Posted by: Tre107 ()
Date: February 18, 2018 01:58PM

I bought some cobalt drill bits and they did not do the trick

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Re: Broken studs in exhaust manifold
Posted by: MattNall ()
Date: February 18, 2018 02:03PM

Bummer!! Find a friend with a Torch, or an old school muffler shop.... to blow it out.





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Broken studs in exhaust manifold
Posted by: Tre107 ()
Date: February 18, 2018 02:11PM

I have a oxy acetylene torch think that would do it ?

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Re: Broken studs in exhaust manifold
Posted by: MattNall ()
Date: February 18, 2018 02:16PM

That's what a shop would use..

Do you know how to CUT with a welding tip?





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Broken studs in exhaust manifold
Posted by: jetcat ()
Date: February 18, 2018 02:25PM

I just fixed a couple of manifolds last week. Both had broken studs. Tried to drill one out but didn't do the threads any good. Wound up putting in a .5" long 3/8 × 16 Time-sert in. That fixed that one. The other I welded on nuts to the remaing studs, heated the manifold area by the stud till it was orange and dipped it in water. Both studs came right out. It worked awesome! Bought some new Dorman studs that Dave Moto used in a pair of 140 manifolds I bought from him recently and they were both back, ready to use.

Bob
Paso Robles, CA

Central Coast Corsa
1966 Turbo Corsa convertible
1966 Corsa 140 coupe

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Re: Broken studs in exhaust manifold
Posted by: Tre107 ()
Date: February 18, 2018 03:04PM

Yah I know how to cut with a welding tip

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Re: Broken studs in exhaust manifold
Posted by: MattNall ()
Date: February 18, 2018 03:09PM

Blow it out!





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Broken studs in exhaust manifold
Posted by: Tre107 ()
Date: February 18, 2018 03:33PM

Ok thanks for the idea I’ll try it tommarow and let you know how it goes

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Re: Broken studs in exhaust manifold
Posted by: Frank DuVal ()
Date: February 18, 2018 09:38PM

I do what Caraholic says here in the rusty east. I do not try to remove the broken stud, just cut off stud if it protrudes, grind flat, drill with small bit, followed by 5/16 bit, tap 3/8-16. Use plenty of lube on drill but and tap.

Now, if you are trying to drill a drill bit..... get the torch and heat the drill but cherry red and let cool slowly to remove the hardness, then drill it out.

I do know how to sharpen drill bits with a bench grinder, so my 5/16 bits get quite short doing this drilling procedure!grinning smiley Sharp bit works wonders. Dull bit makes slow going.

I do use the heat to dull red and quench with water or mig weld nut onto broken bolt for most every other broken rusty bolt, but I gave up on using that method for exhaust logs.

Frank DuVal

Fredericksburg, VA

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Re: Broken studs in exhaust manifold
Posted by: dolomitefan ()
Date: February 19, 2018 01:34AM

I have to fit a new exhaust to my van. I put some penetrating oil on the nuts yesterday and I was able to move them slightly. I suspect though that I'll be lucky to undo all 4 without breaking a stud long the way. Now ideally I don't want to remove the manifolds so if I have a problem I'll have to try and do it with the manifolds installed.

I'm really not looking forward to doing the job to be honest. I've done a similar job on a Triumph and that involved a broken stud but the manifold was easy enough to remove. Trouble is that my exhaust is pretty shot, there's only so much exhaust hole paste you can construct a system out of.

---------------------------------------------------------------
Mark Gibson, Staffordshire, England

1961 Corvair Greenbrier
1980 Triumph Dolomite Sprint
2009 Mazda MX5
2015 BMW 1 Series

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Re: Broken studs in exhaust manifold
Posted by: Darrin ()
Date: February 19, 2018 05:29AM

Has anyone used a plasma cutter to blow out the stud?

Darrin Hartzler
Bethesda, MD

Corvairs in two states of the Union and varying states of disarray.

Northern Virginia Corvairs & Group Corvair

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Re: Broken studs in exhaust manifold
Posted by: toms73novass ()
Date: February 19, 2018 05:48AM

I do not think a plasma would be a good idea, with that thick of metal the arc could wander/bend in the cut and it will not discriminate between the cast and the steel of the stud. With oxy/acydelene the stud gets much hotter then the mass of the cast iron surround and when the extra oxygen is introduced it attacks the steel not the cooler cast, if done correctly.

-Tom


63' Monza Spyder Convertable (in process) MY Build Thread
73' NovaSS 454 Big block
86' BMW 325es
98' Dodge 2500 12v Cummins Diesel with 1200 lb torque!
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Grand Island, NY

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