Several years ago, I was removing my Y-pipe and sheared off the lower bolt to the manifold on the passenger side. It broke off flush so there was nothing to grab on to. I have since returned to this project and after reading the horror stories about "easy-outs", I decided just to drill it out in incriments, especially since the bolt hole runs all the way through. I figured if I screwed it up a little, I could at least run a bolt all the way through and tighten it down. There is ample room to drill, and so I center-punched a hole dead center and began drilling away with a titanium-coated 1/16" bit. It bit right in and was cruising along pretty well until it snapped. It was only in by about 1/8" and I was able to pull the broken piece out. Well, I shoulda paused after that one. Instead, I grabbed the next size up and went to town. It went in a pretty good ways before it also snapped. This time, however, it was flush! I could not get it out with a magnet or a set of diagonal cutters that I ground down flat. Now I'm screwed almost as bad as the easy out. Of course I tried drilling away at it, but the bits won't bite down very well and now my hole is no longer centered. I was PISSED! It was going so well and now I'm stuck. I went to Lowe's and AutoZone and grabbed a variety of their "strongest" metal bits. 135 degree split, titatium, cobalt, HA, this thing LAUGHS at this stuff. I spent about an hour solid going from on bit to the next and was only able to "wallow" out about 1/16". If I could get a smaller bit, say 1/8" that would really bite into this thing and go all the way through, I believe I could finish it with the others (also have left-handed to try towards the last). Any ideas or know of what brand and where to get a drill bit worthy of this task?

 

i broke off all 4 of mine (both sides) when removing the exhaust, i think the machine shop charged me $40 to drill out the old studs and rethread the holes. might not be the answer you were looking for, but you are probably getting close to $40 worth of drill bits.... if nothing else, pull the whole manifold and put it in a drill press and use lots of cutting oil, and go slow. also, you can come at it from the other side if the manifold is off.



now i just need to get some new studs.

 

If the broken stud is stainless then going slow with plenty of cutting oil is the key. You'll have to lean on it pretty hard but when drilling stainless it's slow slow slow. I think you've got the right drill bits though, they don't come much better than that.

 

I had thought of that, but I know that once I dive into the manifold removal I will surely break some of those and that will REALLY be a pain. Yes, I will be right at $40 worth of drill bits before this is over, but the experience has been priceless!

I read some more threads and I'm thinking of getting a carbide-tipped bit from www.mcmaster.com

 

if i understood correctly his problem is getting through the other drill bit that already broke off in the stud... never any fun, but doable if you have more patience than i do.

 

well, like i said, all 4 of mine broke off, but the manifold to block bolts came out fairly easily. ymmv though...

even with it on the car i would still try to come at it from the other side, so you are not drilling through the broken drill bit. that way it will just push it out when you get there, if there is even enough room.

 

At this point, I am expecting the worst case scenario which would be broken bolts in the head. Right now, I really just want to get this back on the road. If I remove the manifolds, I'm replacing them with headers.

 

when you say broken off is it broken off even with the head or even with the manifold?
if its even with the manifold you have no problem. unscrew the other bolts and unscrew it using the manifold as a wing nut.
but before you do that - soak that bab boy with lots of gun lube - spray can - fine oil - soaks into everything. let it soak in keep using it until every few hours. until the bolts come out easy. dont want to break another one.
good luck.

 

I dont get what you did cause I just skimmed the article.

I can tell you you wont drill out an easy out as it is hardened pretty high up on the rockwell scale.

If you got a metal squirter you can squirt a longer bolt on to it preferebly allen head and back it out.

or you can use a plasma cutter to burn it out.

When your done just weld a hex nut to the flange for your new bolt.

 

It's not in the head, it's the manifold to Y-pipe flange on the passenger side. The bolt broke off flush on the Y-pipe side. I broke a 5/64" drill bit off in the bolt, not an easy-out. I really don't have access to a plasma cutter or else I would have done that LONG ago. I'm going to give the carbide-tipped bit a try and let everyone know how it goes.

 

Just pull the manifold and take it to a machine shop and dont worry about it cause its common and a cheap repair.

 

I've had a couple pretty stubborn bolts, and what I've done is drilled a small hole in the center of a broken bolt. Then I've threaded the hole and put a screw in and turned until enough had come out to grab it with vice grips. This is good when you can see the bolt from the top (which you can) so this may be one of the "easier" ways to do it, IF you can fit a tap in there.

 

Problem is the drill bit broken off in the bolt, not the bolt itself. the drill bit is High speed steel, way harder than the bolt. I've actually broken off easy-outs in similar situations, here's what I do:
1) Using a round nosed, 1/8 inch carbide burr in a dremel tool, start plunging in directly in the center of the bolt. if that's where the drill bit is, the carbide will cut through it. I use the dremel bit as far as is will go down, or until i've reached full depth of the burr (about 1/2 inch)
2) I then continue through the bolt with an 1/8 inch solid carbide, machinist length drill bit either in the same dremel tool, or in a drill if I have room.
This method has worked for me even through easy-outs, which are way tougher than a HSS drill bit. I am a machinist by trade and fix these kinds of things for my friends all the time.

 

That sounds like the best advice so far. I will get one of those dremel bits and give that a try. I already have a carbide-tipped machinist drill bit on the way from Atlanta to continue the job.

 

MAN!! That carbide tip for the Dremel was the trick! It ate through that broken drill bit and bolt like it was a rotton tooth. I was then able to use my regular drill bits to drill out the bolt by progreesively going to larger sized bits. I stopped when I could see threads, but there is still some pieces left inside I think (can't see at the angle I'm at). This hole goes all the way through and technically, I could just get a smaller sized bolt and run it through as is and bolt it from both sides - OR -should I attempt to clean out the hole with a tap? I've heard of taps breaking and that would send me back to square one, so I'm a little hesitant.

 

you *could* try to run the tap through it. however, if you don't have the room to get a proper tap wrench on it, NOT an adjustable wrench or a open ended wrench, that's when it will break. i've done the smaller bolt all the way thru the hole before, and it works. Will it last just as long? No, not really. the other option is to oversize the hole and helicoil it so you have fresh threads, however, the kits also use a tap, so you are still in a tight location, but IMO are a much better repair than a re-tapped damaged hole.

 

Well, there is no way to properly tap that hole without removing the manifold. There is just not enough room. As soon as I would get a good "bite", the T-handle would prevent me from keeping the tap straight while applying pressure. I did use the tap to clean up the remaining bolt holes, though. I am going to run a smaller sized bolt through that buggered hole and use a nut on the backside with a lockwasher and get this thing running again. If I ever need to remove that manifold in the future, it is going to be repaced with headers, anyway, so screw it. Thanks for all of the feedback and suggestions!

 

Glad you've got this thing run to ground.

Dremel tool bit:
I had a similar experience with a rear-disc brake bracket.
I was fortunate enough to have a drill press (very controlled
& accurate), and the part was small.

Let me also offer some insight gained during this experience.
Cost to replace piece: $60 (GM is REALLY proud of this bracket.)
Reasonable labor rate of $20/hr to keep futzing with it.
(Ended up w/ ~4 hr's total.)

Lesson is that replacement may be more economically viable.
Unless you're just into quests. That can include learning useful
stuff from other gearheads, as well as contending with the
accompaning gas-bags.