Broke drill bit off in exhaust manifold bolt...

[RickB]

I sprayed PB blaster on the flange bolts for the past few days, today I got under there and took all 5 bolts out with no trouble.

The one that the PO broke off was a big problem. I drilled it & tried the easy out.

I went & bought a harder drill bit & drilled it some more...

The bit broke off in the hole, not enough left to grab with needle nose...

That's when I gave up for the day.

Any ideas that don't involve removing the manifolds from the head?
/bcforum/images/%%GRAEMLIN_URL%%/frown.gif

 

[Adam58]

No fun there! I used to work at a VW machine shop and I often had to remove broken studs from the aluminum heads.

Is there any of the stud sticking out past the manifold or the head?

If there is some sticking past the head, bite the bullet and pull the manifold so you can get a clear shot at it with Visegrips. If it's flush to the head and you can get a small hard point against the flute of the bit and tap it anti-clockwise, there's a small chance you could loosen it and get it out. If you get the bit out, go back and keep drilling using a fresh bit and a little cutting oil. High speed but not much pressure.

In the worst case, you may have to pull the whole head off so it can be mounted and held rigid on a drill press so it can be removed and have an insert installed.

Good luck and keep us posted! Adam

 

[vping]

Is this the bolt on the down tube ot actually into the head? I've just broken 4 outta the 6 on the downtube and have to figure a way to get them out now?

 

[1965_MGB]

I wish there was a way to get them without removing the manifold, but I have never found a way.

Perhaps you can put a punch on the broken bit, and see if you can break it up, and then drill again.

Things would probably be easier with the manifold out.

 

[RickB]

Re: Broke drill bit off in exhaust manifold bolt..

Not the part up at the head, the down pipe part.

I'll see about drilling another hole in it tomorrow, the first one was to one side so the next will be more towards the other side. Maybe I'll get lucky.

 

[Bugeye58]

Re: Broke drill bit off in exhaust manifold bolt..

Rick, suck it up and pull the manifold, before you do irreparable damage. Take it to a machine shop and have them remove the bolt. Even if they have to do it on a mill, it'll be cheaper than buggering it up and having to pay for a repair or a replacement manifold. With a drill bit broken off in it, it's going to either require enough heat to anneal the bit, a carbide mill or drill, or a combination of both.
Jeff

 

[mikespain]

Re: Broke drill bit off in exhaust manifold bolt..

I agree-as the drilling is already off center,redrilling will probably end up with the same result,better, surer, quicker,cheaper in long run to remove it and take to machine shop

 

[boxofparts]

Re: Broke drill bit off in exhaust manifold bolt..

If there is any bit of the stud showing , even it it is flush, hit it with a mig welder. The welds will stick to the stud better than the cast iron plus it will put some heat into the area.

If you can create enough of a weld tit ..place a nut over the tit and fill the nut with weld.

Take a wrench and turn out the stud.

It might break off the first time but try it again as the stud will now have a real clean surface to take a weld.

Don't be afraid to turn up the welder a bit to get good deep weld.

 

[RickB]

Re: Broke drill bit off in exhaust manifold bolt..

Thanks guys, some ideas there I hadn't considered.
We have brilliant sunshine this morning, just as forcasted.
I am taking a day off work, an MG health day...
After I drink some coffee I will go out there and take another look.

If it comes down to removing the manifold, where do you get new gaskets? Is that something NAPA can get for me?
Is one kind better than others? It's been more than 20 years since I've done any gasket purchases.

 

[RickB]

Re: Broke drill bit off in exhaust manifold bolt..

Vince, did you use any PB blaster or other type of penetrating oil first?

Several days ago I put a ratchet wrench to a couple of mine and determined they had that feeling of "Go ahead punk, make my day". So I sprayed and sprayed them over three days. I was still amazed when they came right out.

Of course I bought new grade 8 hardened bolts and washers for the reassembly. I'll not tempt fate, I've broken my share of bolts in the past.

 

[RonMacPherson]

Re: Broke drill bit off in exhaust manifold bolt..

Why Grade 8, instead of Grade 5?


Reason I ask is Grade 8 is more brittle and will have more of a tendency to shear than Grade 5. Grade 5 will stretch and deform before it breaks, but Grade 8 just snaps.(shears, actually).

 

[sqbsprite]

Just for future reference. This is when left handed drill bits work well. As you are drilling into the stud sometimes they actually cause it to break free and begin to come out. Spray them first with PB-Blaster and add some heat to help it soak in. Also, when putting in the new studs, a little Never-Seize on the stud and nut makes for easier removal next time.

 

[19_again]

The never-seize. lock-tite and the PB blaster are the best jewels so far that I have gained in this forum. Rick's predicament reminds me of the time it took four days in a New Hampshire February for me to change a thermostat on a '65 Comet. I think I broke all 3 of the [censored] bolts and two knuckles. Now with the help of the forum I fly through repairs, why just last night I finally got that light bulb in the radiator to work. just another dead short was all was, as usual.

 

[RickB]

I've busted off a few more titanium / carbide / whatever type drill bits today. I'm taking my new gaskets out now to put it together.

While the back hole on the front downtube isn't what anyone would call pristine, I have no doubt that I will be able to get this puppy back on the road today. Without removing the manifolds, ordering new gaskets, waiting around for them to arrive, breaking who knows what else in the process.

And yes, I will go and buy some never seize right now, before putting the new bolts in. Thanks for the tips & suggestions - hopefully the next post I make will be after success. /bcforum/images/%%GRAEMLIN_URL%%/wink.gif

 

[RickB]

Re: Broke drill bit off in exhaust manifold bolt..

Done.

Back on the road.

Had to cheat a little, but all in all I'm pleased.
Sounds good too, there was an exhaust leak when I bought it, that turned into the flange gasket blowout.

Two new gaskets, everything cinched down tight, sounds perfect! /bcforum/images/%%GRAEMLIN_URL%%/wink.gif /bcforum/images/%%GRAEMLIN_URL%%/laugh.gif /bcforum/images/%%GRAEMLIN_URL%%/wink.gif

 

[Adam58]

Re: Broke drill bit off in exhaust manifold bolt..

Had to cheat a little, but all in all I'm pleased.

You have done well! Care to share any of your cheating ways with us?

Adam

 

[RickB]

Re: Broke drill bit off in exhaust manifold bolt..

I got most of it drilled out, messed up the threads.
There was enough room to fit a 1/4 inch bolt so I used that with a washer and a nut. That's what I call cheating, but it did work.
I figure it's been going with only two bolts for a long time, it's gotta be better with two 5/16 & one 1/4.
Call be a scab if you will, but the job is done.

We went out and celebrated our 20th anniversary tonight, we went in the MGB.

 

[jlaird]

Re: Broke drill bit off in exhaust manifold bolt..

Knew that was what you had done. Been there done that, why not.

 

[RickB]

Re: Broke drill bit off in exhaust manifold bolt..

At least if I ever do this again on this car it won't be hard to get that one out! /bcforum/images/%%GRAEMLIN_URL%%/yesnod.gif

Trouble is, when you keep buying 'new' LBC's you only get to do this kind of thing once (unless you are Jack...). /bcforum/images/%%GRAEMLIN_URL%%/wink.gif

 

[blhazzard]

My attempt to remove lower rear manifold stud...
i am now removing head...
Any guesstimates what hardened seats and valves would cost ?

Pic rotated CW 90deg

67 TR4a IRS
car has history of blowing out exhaust gasket 40k miles or so.
think this stud just got baked (annealed ?)
all other studs came off with lots of muscle.
note blowby scoring on head flat ...