bolt frozen in head, eeek!

[monsterdog]

One of the bolts for the first intake runner sheared off
just beneath the head of the bolt. Looks like coolant from
bleeding the system over the years has corroded the threads,
and I don't want to make it any worse. Any suggestions
on how to get the bugger out? What extremes can I go to
without risking damaging the head?
Darn monkeys....

Makes me wonder about even bothering with changing the turbo
gaskets. Yikes.

[scheistermeiste]

stud puller

[ae1969]

A few options.....

If you are pulling the head it would be ideal and you can work on it on a bench..........

- You can actually double nut the remaining stud....... or stud puller as was mentioned.

That bolt only has 20 NM on it so it wont take much to get it loose. If you find your self REALLY puttin a lot of force....

Apply HEAT........... Propane........ or MEPP would be better. To the surrounding area not the bolt that remains...

Try and wiggle it back and forth.... Dont get to carried away. Slow like the tortoise.

[Usmellgass2?]

You still have enough stickin out to get a handle on it, Thats a good thing! To avoid maybe breaking it off flush with the head (thats a bad thing!) I would be very careful. Here's how I would do it.
Run 2 nuts down on the stud. leave about 2-4mm of stud protruding out the top of the top nut. Weld the top of the stud to the top nut. TIG or Gas is your best bet. Do NOT cool or quench with water ect. As the stud cools rap gently with a hammer from the top like a nail, not from the side. Do not bend the stud. As the stud cools soak the stud with a release agent like PB Blaster, Liquid Wrench, Krull oil ect. Be careful the top of the stud may be hot enough to flash the penetrante and burn. Hopefully the hammer will help break the corrosive bond and the heating/cooling will wick the oil into the engaged threads. Very carefuly start working the stud back n forth till it will unscrew.

Good Luck!
NE1 else have any ideas lets hear them!

[Usmellgass2?]

PS the aluminum head will pull the heat out of the stud and into the head rather quickly, This will work to your advantage.

[Verruckt]

Can you get two nuts on that stud? If you can, getting it out will be pretty easy with a little heat.

[fast924S]

I would just spray it with PB blaster and grab it real good with a vise grip and start turning. If that doesnt work then its time for heat.

[monsterdog]

allright, thanks for all the advice - i got two nuts on there
and tried to work it back and forth with a little heat
and penetrant - nuts were as close to the head as possible.
with slow, constant pressure it looked as if the bolt was starting
to ease out, and just as i yelled out "it's miller time!...,"
the bolt sheared off again with about 1-2mm protruding
above the head - needless to say i'm not a happy camper

one thing i noticed about this bolt after comparing it with the others
is that this bolt is (or was....) threaded all the way to the hex
head, where the other ones had a non threaded portion at the top.

it looks now like i will have to drill it out and try using a stud removal tool?
i've never done this before so i'm a bit leery, especially if this bolt is
a different length than the others, e.g., if the threads do not reach as far into the
cylinder head. doesn't look like there's much meat there
and i don't want to drill all the way into the cooling passages.

whatever the case - it's really stuck in there - i'm worried that the
extractor may just shear off as well...

some old timer told me to try using heated beeswax as a penetrant.

i'm trying to avoid taking off the cylinder head as i'm not confident i could
do the work correctly, and just thinking about all of those rusted exhaust
bolts is enough to make my skin curl.

wish the bolts were hardened like they were on an old mercedes 280se4.5
junk bucket i monkeyed around on in high school.

next step?

[Zero10]

I was afraid that might happen.
Okay, time to center-punch the remenant of the bolt, and start with a very small drill bit, light pressure, and go straight through the center. You can be 99% sure that you can't go through into a coolant passage, because there is some space underneath the bolt, since it came part-way out. So, you'll feel when you get through the bolt. Use some ATF to keep the shards and metal dust down, as well as to cool the drill bit, and take your time. Step it up one drillbit size at a time, it helps if you have a drill index with 30 or 40 bits, it will take time. Eventually you will reach a size where you can see the little shards still sitting in the threads, and you can peel them out. Usually if you can get it all started very close to the center of the bolt, and you only step up a small amount at a time (drill bit size-wise), you can peel these out with no damage to the threads.
Before you do this, spray some penetrant on it, and once you have a hole through, spray some down underneath.
This might help free the little left-over shards from the threads when you are done.

I've done it several times. Worst-case, you'll end up putting the manifold back on to establish the center of the hole, drilling over-size, and using a helicoil or a time-cert to get it back to stock size/thread.

[Usmellgass2?]

I agree with Zero. Time to drill or burr it out. Tedious work often done with a mag drill. 2 things I would like to add to Zero's advice,
1 It is very important to start with a well centered hole that will stay centered when you start to remove metal. Try to flatten the top of the broken stud with a flat faced punch that is small enough to not damage the threads in the head. Then, useing a prick punch very carefully set the punch to the center of the stud and tap VERY LIGHTLY. If the punch mark is not in the center of the stud lay your punch over at a 45deg angle and move your punch mark (gently). When you have a punch mark in the center of the hole it is time to remove the stud.
2 A mag drill positioned of the manifold gasket surfaces will work the best. using spacers and a steel mounting platform will provide accuracy (rent one as they are expensive) or try it by hand. Use reverse drill bits (left hand) as they will most often back the stud out as if it were never stuck.

[Usmellgass2?]

If left hand bits are not available reverse your drill motor periodicaly to see if the stud will unscrew. Be very carefull with extracters/easy outs. If you break one it must be removed befor you can contiue to drill. When you can see the aluminum threads of the cyl head use an awl and a tap to remove the remnants of the stud.

Good Luck

p.s. excelant photos

[Granite 944]

My opinion.....if you don't have experience drilling out bolts , AND using extractors/easy outs ...............DON'T USE THEM! Get some help, take it to a shop, or something else. Otherwise........your just gonna dig yourself into a MUCH bigger hole. Heat applied to the bolt area should have helped tremendously. Since it only slightly helped........the "touch" is NOT there. Get help. Good luck!

[yieldsign2]

Just so you know, if you do break off an extractor in there, they do make drill bits that will go through extractors, but they aren't cheap.

[bigyagi]

get this all the time, at the tooling shop. worst case scenario, if the easy-out breaks, get a hold of some carbide drills, or small carbide end-mills.
its extremely important to center punch at the exact center of the bolt. once you have drilled down with the first drill, if you find that its off-center a little, you can start the next one, drilling at a slight angle, to "recover" the center, then go straight down again. a porta-mag drill is very helpful, but its possible to do this just as well, with a hand-drill.
try to use the biggest easy-out, that will fit inside the bolt. if you cant budge it with this, then its time to keep stepping up in drill size, until you can start to clear the bolt threads, with a small pick. be careful, as you do not want to damage the alloy. the idea is to try and collapse the threads. sometimes a good idea to even run a smaller size tap down the hole, before getting close to size, then running the correct size tap thru.
if it all goes south, take the head off, and go to local engineering shop, where they will do this for you{whatever level of repair is needed} with no problem. just requires a little cash.
good luck.

[ae1969]

At this point.

Drill it out. Clean the hole. HeliCoil and be done with it.

OR

If you know someone that can weld..........and I mean professionally.

You can still place a nut over that segment. Build up the area with a rod and still be able to unbolt it.........

Just had 2 done this weekend for a friend that had 2 seized bolts with extractor bits in them.....

[bryanthompson]

Find a machinist who will come over and do the extraction for a 12-pack.

[monsterdog]

Thanks for all of your input. Gonna drill the little sucker out,
if I can salvage the threads I'll reuse it, if not then I guess
I will be introduced to the miracle of heli-coils.

Would a regular metric replacement bolt work in place of the original with
some washers, ot should I bother getting an original replacement?

[ae1969]

Get some new hardware........ but if you want to drive it while you wait for that $2 bolt......... go ahead and use anything you find.