Specific advice needed for broken bolt
 

I have read some other threads on how to deal with broken bolts/studs, but I'm hoping for some case-specific advice on my situation. I just received my new 3.2 engine and one of the 4 bolts that tie the engine to the tranny has been broken off flush with the engine surface.

The PO of the engine advised me of this situation before shipping the motor. It happened as he tried to seperate his transmission and he ran out of time to fix it before having to ship the motor. There are no hard feelings but I am left to deal with this myself. As you will see from the pics below, he did start an attempt to drill out the broken bolt, but his initial drilling is well off from dead-center on the bolt.

I look forward to your collective advice on this one!! Thanks!


http://forums.pelicanparts.com/uploa...1212703308.jpg

http://forums.pelicanparts.com/uploa...1212703330.jpg

http://forums.pelicanparts.com/uploa...1212703346.jpg

A center punch (To aid drilling a more centered hole) a series of drill bits (probably three) and a set of easy-outs would probably get you where you want to go.

The off center hole is a bummer and will make this harder than it otherwise had to be. If you were to start with a very small drill bit and a center punch you may still have room to make a hole closer to the center. Light pressure while drilling with successively larger bits and some luck could keep you from falling into the existing hole. A set of Craftsman easy-outs will hopefully do the rest.

Same thing happened to me last year when my 2.7 fell off the farking stand. Bottom stud pulled out of the case; when that one let go, the top stud just broke right off. I repeatedly heat cycled it with a torch, and doused it with penetrating fluid daily for a few days. Then I cut a slot in the broken-off stud with a dremel. There was some inconsequential collateral damage to the case, just cosmetic. Very little depth was needed to get the slot I needed.

After that it turned right out with a screwdriver.

Oh, almost forgot the obligatory kick in the nuts: this never would have happened if you bought my engine ;)

i would take a round burr die grinder and cut a big concave dimple in the end of the stud so you can get a drill bit centered. the drill hole doesn't look too deep, so maybe the dimple will get past it so youcan centerpunch right in the middle and drill a small pilot hole. drill as large a hole after that as you can and use the biggest easyout as possible so the chances of it snapping off and compounding the problem are lessened.

You need to start with a very small bit to get the center of the bolt started - from there go up in sizes - slowly and with minimal pressure. Use a corded drill - must cordless don't have the higher RPMS

This is a great start - - thanks guys. Sounds like I have some options.

LOL - thanks a lot, Dave! And thanks for the advice, too :)

What they said. I have only one thing to add. Be patient. Very patient. When your patience starts to fade, quit. Resume the following day.

Oh, one more thing. Two, actually. I like the Snap-On screw extractors. They are not as spendy as you probably think, and they work better than the others. Also, there are reverse drill bits. About half the time I use them, the stud comes out while I am drilling.

Since the hole is off center, you may try (after soaking w/PB Blaster a few days) try to tap it out with a thin round punch. Put the end in the hole, hold it at approx 15 degrees parallel to the case, and tap it out. Hard to explain, but picture unscrewing it using the tapping motion, you'll have to follow the hole around as it unscrews. I've had success in the past using this method.

Good luck

Dave

Wouldn't a trip to a machine shop that has a decent drill press and about $40 do it? Let someone else sweat while you spend your valuable time prepping the engine compartment.

+1

I hate easy outs!
You know you're in a bind when the darn thing breaks off in the bolt... Try drilling that out!
I would try to plug weld a nut to the remaining bolt but i don't know if this would be practical in this case.
Good luck!!

Exactly what I was thinking, of course I have a few welders handy.

easyouts work fine as long as you know your limits. big as possible and slowly take up the tension to get the stud moving. you can feel when it ain't going to work long before you break it. you just don't crank on it gorilla stlye until it breaks. the stubby snap-on ones work great. drill large enough to just get the tip started, then tap it snug with a hammer.

The guy who does my heads (Bob and Atlantic Enterprises) also goes around to shops drilling out broken off head studs and such. He uses a small burr on a die grinder just like JW said. The reason this works is that, unlike a drill, you can "steer" the burr to get it in the center of the bolt. Then use the dimple you made to center the drill.
-Chris

+++++++++++++++++++++++++ always works for me.

+1- I had a broken bolt on the water pump of my blazer and the drill got off to the side and into the threads much like yours the die grinder worked great got me centered up, I went ahead and drilled it all the way out and tapped for a timesert the whole thing is just as strong as the original hole.

Status Report
 

Okay guys - here's where I'm at.....I tried Dave's Dremel idea (cutting a notch for a big screwdriver), but the available angles of attack just weren't conducive so that approach was abandoned. However, I did do just enough with the Dremel to provide a "punchable" indentation at the bolt's center. This got me started with a small drill bit in (more or less) the center of the bolt.

I went to Sears before starting anything and picked up this little kit:

http://forums.pelicanparts.com/uploa...1212755565.jpg

I started with the smallest bit and fought my way into the center of the bolt. Then I went to the next larger bit and made even more headway.

http://forums.pelicanparts.com/uploa...1212755810.jpg

On the third bit things started to go wrong. Either my drill doesn't have enough power or the size jump from the 2nd to 3rd bit was too large because I couldn't even get started without binding up. So I went back to bit #2 (7/64" maybe?) to try and wallow out the hole a little and *snap*! Broke off the tip of that 2nd bit. :mad: I could not readily extract the broken tip so that's when I decided to quit for the evening.

It looks like I need a very small set of needle-nose pliers to get that tip out of the hole. I should be able to get it out, but then what? Do I try to find a bit that's in between the 2 sizes in my kit? I'm planning to return the extraction kit to Sears and see if they will replace it......or should I be looking at a different kit? I was looking for the "Easy Out" name, but could not find it. This kit looked okay so I bought it. If I do stay with this type of kit, what should I be using to apply torque to the extraction bits? A tap wrench? Square sockets?

Thats hardened steel if you cant get it out with the pliers then you really need to go the die grinder route ( ask me how I know) the different hardness of the bit will push any drill attempt off to the side into your other hole.

The bit should come out with a little influence, when it does get a standard indexed set of bits.
Drill it out with smaller jumps in bit sizes.
The reason I like the plug welding method is because the heat from the welding usually will help expand then shrink the bolt as it cools making it easier to remove.
Once the extractor method has been unsuccessfully used, there is nothing to weld to if you are still in a bind...
I have rented magnetic base drill presses and drilled out the bolts and picked threads clean (very time consuming but doable..). If very careful you could do this free hand.
Hope you have better luck today!