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Broke Exhaust Studs: How to remove them?

39K views 50 replies 16 participants last post by  cn90 
#1 ·
I am in the process of replacing the Giubo, CSB and re-grease the Rear CV Joint.

In the process of removing the exhaust, I broke 2 studs (the nuts just came off with the broken studs. This happens even with spraying with PB Blaster and heating the nuts with propane torch for a good 1 minute!

Now I have 2 broken studs to remove, is there any trick to remove them?
- I have a puncher...should I use this with a hammer.
- Drilling them out: the space is so tight, I may have to remove the exhaust altogether to do this.

Please advise on how to remove the remains of the broken studs!

 

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#2 ·
If you have enough space I would just hammer them out and replace with a nut/bolt combo. I had to do this on my Volvo.
 
#3 ·
Wow,, that s**ks. You can't get your hands and or tools in there to take the header out of the car I suppose. Do you have access to an Acetylene/Oxygen torch? If so I'd try to heat the metal and with a long drift punch out the two studs. Getting the new ones in will be a little trickier but not impossible I'm sure. Barring heat I don't know how hard I'd try to beat on those studs to get them out.
 
#5 ·
I think you'll find removing the exhaust manifold it the quickest and easiest way to hammer them out.
They have a spline in the part that goes thru the flange, good luck.
 
#6 ·
This is one of the worst jobs ever,save yourself a massive headache and take it to an exhaust shop where they can use an oxy/acetylene torch and an air chisel . You can hammer them for ever they just
don't seem to move.

Drilling with cobalt drill bits is another option ,starting with a pilot hole and then increasing bit size,drilling slowly with plenty of lubricant.

This is not a pleasant job upside down under a car believe me I've done it.
 
#7 ·
Well heat and punch will be your best bet for now. But I doubt they will come out. Easiest way to be use a acetylene/oxygen torch as it will heat up the area slot better and faster. And of course you want to heat up the flange itself and not the bolts.

I say give it a try with the propane and a punch/chisel with a nice 3lb-5lb hammer and if you have no success pack it up and take it to an exhaust shop and have them do it.

Or be an ass like me and do all the work with the exhaust hanging. And after your done take it to an exhaust shop to get the flange repaired. It's doable if the cars on ramps and you loosen up ALL exhaust hanging hardware so it's just hanging by the header. Just use something to keep the exhaust from hitting the floor all the way.
 
#8 ·
There's an inexpensive tool called an EZ-Out you can get. It's probably the safest way to go about it. These have aluminum heads, no? If they are you've got to be real careful with them! Very easy to jack them up. Hammers and torches would be my last choices after the EZ-Out. https://www.google.com/webhp?hl=en#hl=en&q=ez-out Check them out. I think you'll like this!
 
#10 ·
A small butane torch may provide enough. I know they burn hotter than propane. They can be had for ~$15. They also sell a small, portable Oxy/Acetylene set-ups at most tool and some hardware stores, but may be more than you want to spend
 
#11 ·
Get the flanges cherry red with an oxy/acet torch and use an air hammer to drive out the broken studs. Less damage done with this equipment.
 
#13 ·
Thanks everyone for your replies.

Brief update:
- Bank 1 (cylinders 1-3): no broken studs
- Bank 2 (cylinders 4-6): broke 2 studs flushed at the nut side, so there is about 5mm sticking out of the remaining stud, this helps alot b/c I needed the car, so bolted everything back together. Even with a single nut holding the seal is pretty, no leak I can hear even on full throttle. But I will fix this issue soon.

Talked to Muffler shop:

1. Removing Manifold: not a good idea since you can break more studs.

2. Heat (they use propane + Oxygen) to red hot, then air chisel it out.
They say this is the best way.
I will bring my stainless steel bolts/nuts, don't want to go back to this spline-wedge-type bolt business.

You see, if they fit the standard bolts and nuts (not spline type), then even if you break the nut: no issue, remove the remaining bolt and install new ones!
 
#15 ·
With the flanges red hot, the studs will come right out. I'm sure the shop will have the correct attachments for the air chisel to drive out the studs without ruining the flanges/exhaust manifold.

BTW Cam-an air chisel will ruin about anything you can imagine of not used correctly. Lol.
 
#16 ·
nope nope....

Drill the remaining stud out...

welcome to nut and bolt and lock washer style...

Dont air hammer on the manifold..

*you might be able to get it to pop out the back side... but that would be a last resort

Id do it like this.. heat and punch, drill and punch. hammer and punch
 
#17 ·
They only use the air chisel until the splined part of the stud is released and then it should just tap out with a hammer- no damage to the flange.

I fitted stainless steel nuts and bolts which should drill out easily if need be.

Im sure BMW use some special hardened alloy for their studs .
 
#18 ·
Im sure BMW use some special hardened alloy for their studs .
^__yes they did, you're not going to drill them with cheapo bits. Stainless is not much easier to drill out either. If you go to stainless don't over tighten them or you'll gall the threads making it difficult to get the nut off.
 
#32 ·
nice,,,,, herrraaaaaaaaayyyy for expatiation and contraction

dont forget about what jim said.... stainless's gall's

regular good old carbon steal




$Tips from the stainless steal plant $
you can spit on stainless and it will not gall..
anti seize will not protect you from galling
 
#34 · (Edited)
A little update.

- For the past week, the Bank #2 Exhaust Flange is held by only 1 bolt, interestingly no leak. But I want to make it right, so...

- RF Tire up on ramp again.

- Drilling upside down is not fun! So I invented a little trick: scissor jack under the drill and slowly crank it up as I go.
It was in fact very pleasant b/c my hand does not have to press the drill against gravity. In fact, it is almost no effort at all (other than squeezing the trigger for the drill to run)...
After 1h, went through half of the bolt. That is with the most expensive drill bits made for steel (the brand is Bosch, made in Germany drill bits). I got fed up b/c drilling takes so long.

- Then I decided to change technique: used the tie rod puller. It pushed the remaining stud for about 1mm, then the bolt head made contact with the other side of the tool, which I was not aware of until later. Kept cranking, but went no where. Only after I removed the tool that I found out the bolt was bent.

- Once the remaining stud is pushed 1mm out by the tie rod puller, a punch + hammer was a piece of cake.

- Then new SS bolt/nut from Lowes hardware worked great.

If I do this again, then tie rod puller only to break the bond of the remaining stud, then tap it out. This way the tie rod tool is not damaged.

Anyway photos time...





 

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