Valve Cover Bolt Sheared - Best Way to Remove

[1990new]

I'm replacing the valve cover gasket on the 1989 automatic that I bought on Saturday.
The left front valve cover bolt is sheared off at head level. (I knew this when I bought it.)

Here is a link to the folder which shows the problem:

https://picasaweb.google.com/105052195308338442517/1989FestivaValveCoverReplace?authuser=0&authkey=Gv1sRgCN7y55bygqWZ1wE&feat=directlink

I need advise from someone who has successfully remove one of these without damaging the head.
Would like to get it out and be able to keep the threads in the head intact.

Open for suggestions?

[RhodeStiva]

easy out set. it helped me with a broken head bolt i am sure it will work on that.

[zoom zoom]

very small easy out very carefully! Your gonna have to drill a hole in the center of that!

[1990new]

I have an easy out set, and been trying to drill the last 20 minutes but I've not had any luck with any of my drill bits cutting into that steel bolt.

Can some suggest a size and grade of drill bit I should buy to do this job? And where I can find it.

[bravekozak]

Do not use a cobalt bit use a brand new black oxidized drill bit. They are cheaper and will cut in better. Their point has more of an angle and isn't as flat. I always center punch before drilling so that the bit doesn't wander. Too bad the head wasn't off the vehicle. Then you could have the bolt shank head spot-faced so that it could be drilled dead center. Good luck.

[1990new]

Do not use a cobalt bit use a brand new black oxidized drill bit. They are cheaper and will cut in better. Their point has more of an angle and isn't as flat. I always center punch before drilling so that the bit doesn't wander.

Thanks Dan... I'll Google it to see where to buy these. On this one, somone had already drilled a small hole close to the edge and looks like
they broke off the small drill bit in the hole. I think I can use the punch and miss it drilling down the center. What do you know about left hand drill bits?

Would this do the trick?

http://www.lowes.com/pd_316855-68082-9227_0__?productId=3340802

[RhodeStiva]

And lay a magnet next to it so shavings don't go every where.

[bravekozak]

I know they come in sets and if you break one like I did, you have to buy another set. I got mine on the Bay. If you just even tick that broken bit, the drill bit you are drilling with will probably break. Is there any way to get that other broken bit out?
Based on what was described, surgery is recommended. Really, you need a very small drill bit in a drill press drilling out the remaining meat in two places. not the center. I wouldn't risk it. If you truly want to save the thread, take the head off and take it to a machine shop. Using a hand drill to achieve the required precision is almost impossible on an M6 bolt with a broken bit already stuck in it.
You can buy black oxide drill bits individually if necessary.

[zoom zoom]

haha, looking at it again, you could almost use another small bit to drill a shallow hole beside the current hole and use a flathead screwdriver to twist it out of there ^.^ Maybe a impact driver with a flathead bit? Maybe even a grider or a dremel tool to cut a nice slit in it...

[1990new]

Magnet..great idea, Thanks Rhodes,
Don't really want to take the head off yet. Just got the car this past weekend (79,000 original miles) and I want to run it a while to make sure there are
no other problems before I start tearing it down. It ran great on the 100 mile trip home (except for the loudness from the holes in the exhaust pipe).
If I can't get the bolt out by one of these suggested methods, I'll just put the new valve cover gasket on and put a little C clamp at that edge and see how it holds.
Appreciate all the suggestions... I'll get back at it tomorrow and post my results.

[WmWatt]

Soak the stub with penetrating oil 2-3 times a day for as many days as you can wait before attempting extraction.
Hit top of stub with hammer and punch, large nail, or similar each time penetrating oil is used.
Clean away any debris with wire brush to make sure thread is clean.
Heating the side of the block may help but I'd get confirmation on that before trying.

[jms0924]

Hey Jesse,
Give me a call if you don't have any luck. All the advice above is good, but there may be a few contingencies that can hamper your success. I believe I can give you enough info in 5 minutes on the phone to get you through the challenges, and get the thing out without removing the head. Looks like you have great access to it. Do you know if the bolt was broken by overtightening? ..Corrosion? ..crummy threads? ..wrong fastener installed? ..Other? Don't fret, you can always heli-coil the thing, if it's already gotten too "boogered" - still without removing the head.

Let me know if you don't have my number any more. Call anytime 7a-11p EST.

Best,
Jeff

[1990new]

I've spent about $35 on drill bits, cutting oil, and other tools trying to get this bolt out and none of the bits I bought will cut into the bolt.
I think from all the drilling attempts, the bolt has become hardened to the point that nothing will cut into it.

However, something that jsm0924 suggested for creating a jig to center the drill, has become my short term solution to the problem.
A piece of angle iron bolted to the side of the head with the other angle sliding over the valve cover edge. The screw is to keep it for
slipping left as I tightened. Hopefully it will provide enough pressure to keep that corner sealed. Changed the oil and ran it about 5 minutes.
Appears to be doing the job...we will see as it is driven and remains hot for a long period.

Thanks everyone for you suggestions.

https://picasaweb.google.com/105052195308338442517/ValveCoverSealReplaced02?authuser=0&authkey=Gv1sRgCIfEjOPClsjF4AE&feat=directlink

[kingstonpygmies]

Don't know if it will be good for this application but I have welded (or jb welded) a nut onto the broken bolt and backed it out from there. Or just left it and tightened it down on a few occasions. Oops

Sent from Kingston Ga from my hillbilly handheld

[1990new]

Don't know if it will be good for this application but I have welded (or jb welded) a nut onto the broken bolt and backed it out from there. Or just left it and tightened it down on a few occasions. Oops

Sent from Kingston Ga from my hillbilly handheld

I've read about that being done. Might work here but since it's a 6mm bolt it might be hard to weld a nut on the indented stud and not damage (melt) the head seal surface.