I'm sure this topic has appeared before, but would really like your input.

My 1962 exhaust manifolds have several broken studs in the lower flanges. At Sears I found and purchased a set of hex nuts which have splines on the inside and, when driven over a stud, work great to remove them (they were rust-welded in).

The remaining broken studs are flush to the flange, having sheared when I removed the exhaust pipes. I haven't had a lot of luck with the process where you drill a hole, drive in screw extractors with the twists on the ends and remove. Does anyone know of a similar set of screw extractors to those with the splines? It has occurred to me that, by driving a splined extractor into the hole the stud receives even more pressure to resist extraction since what's left of the stud wants to expand outward against the sides of the hole. Any words of wisdom?
Thanks, Ken

 

i have never had too much success with the insertion type. only about 2 out of 10 work. the back out bits usually snap and fly across the garage. soak it with pb blaster and apply heat with a torch before tristing out. goodluck

 

center punch and drill for the proper tap size....then tap them...sometimes the old bolt will be cleaned out by the tap..[ if you get the center punch right]... if not new threads will be cut anyway....

 

I had one that was impossible to get out so I had a shop remove it with EDM.

It worked great and I think it was only about 20 bucks.

 

i invested in a set of left handed drill bits after my neighbor showed me the way

punch the stud, and drill out the center, with a regular handed drill bit, keep going up insteps in diameter, with the regular drill bits, and when you get somewhat close to the i.d. of the threads, use the left handed drill bit on a slow speed, when going slow, the bit catches, and with the material removed, it almost always cleanly unscrews the left over stud threads without any damage to the original tapped hole threads.

Now if they are totally rusted together as one, they might not be saveable by anything but drilling out and the next size up tap.

I broke off a stud extractor inside the remnants of a bolt in the rearward oil pan bolt of a big block I was wrenching on when he showed me this trick. We punched the piece of extractor thru the bolt, , used a lefty, and it cleanly unscrewed the remnants, and out came the broken piece of screw extractor behind it.

 

Absolutely the best advice. Last thing you want to do is drill a hole, insert an Easy-Out or something similar and then break that off inside your manifold.

 

Have used a technique that works for me. Center punch and drill it centered as well as possible, up to close to the minor thread diameter (just before touching the threads).

I then use a Dremel tool with a diamond tip (1-1/2" long, 1/8" diameter shank with industrial diamond grit up about 1/2" of the shank - but they come in several shapes). The diamond tip will cut just about anything, including broken off "Easy Outs", taps, drill bits, etc. Once you start cutting with the Dremel, you can see the very tip of the threads. Think of this as "playing" Dentist and removing a cavity, but you are on the good end of the drill/tool. With some skill, you can then just "pick out" the rusted in threads of the broken off bolt, and they will sprial on out. The old threads in the manifold are then almost good as new, after running a tap through them with a suitable lube.

Have found the diamond tipped tools at Sears, etc. Not cheap - last time I purchased one, it was about $10. Found a package of them (20 per) at a swap meet for $15 (a real deal - but hope I don't need to use one again, but I am prepared).

Plasticman

 

if it broke off while trying to remove the exhaust pipe, then it is so tight that there probably isn't a snowball's chance in hell that you will get it out. drill a new hole (carefully) and re-tap.
Bill

 

What I did involved a lefty screw.

1. Drill the center of the bolt as large as you can.
2. Use a left-handed tap set to tap the new hole with as coarse a thread as possible.
3. Soak the bolt with PB Blaster...a lot. Soak it again. Next morning, soak it again. 40 years of rust does not let go in 30 seconds.
4a. If the bolt is "proud" of the hole that it is stuck in, then drive a lefty bolt with a hex head or allen head, heat the area, and go to town.
4b. If the bolt is recessed in the hole, use at least two washers as thrust bearings to prevent the lefty bolt head from sticking when you drive it in. Heat the area and go to town.


Good Luck!!

 

Thanks to all!!! All good advice.

In an act of desperation, I went back to Sears during the noon hour and asked a salesperson for assistance (Usually akin to spitting in the wind). This time I was directed to no less than four places in the tool department, all of which had some kind of "easy out" (unbelievable!). I found they carry a set of "bolt extractors" that are tapered and four-sided instead of the usual "twist" type. I am heartened since this is more or less consistant with the spline concept of the outside extractors - the four sides provide four edges to cut into the sides of the hole I'll drill. I will post the results of the use of this product and may be back to following some of the excellent advice everyone provided.
Ken

 

Be careful with the extractors, I had one of the same brand you purchased break once, and it was a helluva time getting out because its hardened. Another trick is to get a left hand drill bit from Grainger. it will bite near the end of the stud and back out on the bit. Dont forget that PB Blaster too.

 

What is EDM?

Jim

 

I Just did this on the water pump bolt on the '59.. It is a PIA Get an easy out (left hand thread, and before anything soak the heck out of it with WD40 or similiar. Center punch it and slowly drill into the center. Also you may want to keep spraying WD40 on it every so often. If you have a torch, heat it as well. BE carefulkl to stay centered. If you have the Easy out, after you drill into the bolt, you will want to insert the easy out and then try and reverse it out. If it seems like it could break the easy out, STOP. If you break an easy out, it will be hell to get IT oout as well. I always then go one size up on the left drill bit and do it again. It is timne consuming, but if done correctly, you can get the bolt out WITHOUT damaging threads.

 

Jim,

ELECTRICAL DISCHARGE MILLING or ELECTRICAL DISCHARGE MACHINING
(essentially the same thing)

EDM is a yet another way of machining objects. Both conventional and wire EDM processes are available.

Basially cutting metal with an electrical spark (either via an electrode or a wire). Tooling dies (for stamping, molding, etc.) use the process considerably.

Plasticman

 

These were never intended to remove items that were frozen in a hole. They were intended for removing bolts and screws that broke off while inserting.

Think about this realistically. If the threads are so rusted or messed up you break a 3/8 inch bolt off (or whatever size), what makes you think a 1/4 inch or 5/16" Easy Out is NOT going to break under the same torque load?

Lesson 1. Smaller bolts break with less torque than bigger bolts. If the big bolt broke, the smaller Easy Out is going to, too.

Lesson 2. Easy Outs and other extractors are hardened. Your drill bits aren't. This means you snap an Easy Out off in that hole, you will be using a torch to get it out, unless you know a safe cracker.

Lesson 3. The machine shop will charge you more to remove the broken Easy Out and rusted bolt than the rusted bolt alone.

Goal in Life: Throw the Easy Outs as far as you can throw them into some field so you are never tempted to use them again.


An old trick to remove bolts is with an electric welder, if you don't have an Oxy-acet torch. Zap the bolt until it glows. The melting point of a steel bolt and the cast iron manifold or engine part it is stuck in are very different and you can do this if you are careful.

Don't do it over your head, or with gas leaking around you, though. Remove the manifold and put it in a vice.

 

Bill

 

Thanks, --Jim

 

 

Like so many of us I too have struggled with broken bolts, studs etc. Having used the new Sears extractors and about all the others made in the last 30 years I concluded that for really rusted bolts as in exhaust manifolds its best just to drill out the broken bolt using the Helicoil tap drill and then install the coil. In the end you will have a much better fastener. The key to success in any of these operations, extractors or Helicoil, is being able to drill out the broken bolt while staying precisely on center. Even in a drill press starting with a center drill it is very difficult to stay on center through the complete length of the hole. In my last trip down the boulevard of broken bolts I needed to remove what was left of the forward most intake manifold bolt, next to the water passage, from the right bank of my 327/350 C-2.
With the intake manifold removed, I made a 1" thick guide block for the Helicoil tap drill, and for the tap itself. The block was long enough to be bolted to two adjacent holes . Drill, tap, insert and life is good again. Yes it's time consuming and you need a set of duplicating punches to make the block. But....it works !!!!
Hgvracer

 

You made a Jig to drill to correct dimension. Standard tooling technique for manufacturing and accuracy of function. Nice! Al W.