Broken mandifold bolt, help!

[gray85]

Ok corvette form people I have a good question. What is the best way to remove a bolt broken in the manifold. My thermostat was bad and I tried to remove it, now one bolt broke without anything to grab.
1. Should I take the manifold out and bring it to a machine shop
2. Is there some pull out tool that can be used.

My car is down and it is my daily driver, any information will greatly be appreciated.

 

[Robertwav1]

I agree with sherry. You might want to start using a penetrant on the bolt and let it sit overnight or better yet longer. Don't be afraid to re-spray the penetrant often. An easy out should then do the job. Be carefull with the easy out....it's extremely hard and can break. Use the largest that the bolt will accomodate. Good Luck!

 

[SPANISHVETTS]

:argue The problems with Easy-outs are:
1. If you let the drill slip off center you will make a real mess out of the manifold. :cry
2. If you drill the hole too small you will need to use a small easy-out which will break off in the bolt.
3. If you drill the hole too big the easy-out will expand the now very thin remains of the bolt and destroy the threads in the manifold, forcing you to rethread the manifold and insert a heli-coil. ad

Papi of Yamaha fame and now the team’s chief wrench and Guru taught me this trick. Make a T handle from a mild steel bar a few mm smaller than the broken bolt. Electric weld this to the broken bolt and unscrew. Use plenty of penetrating oil.

We use this method at least ½ dozen times per week, it works every time and we never strip out the threads in the aluminum part.

You need to have a good welding hand. If you are not an experienced welder find someone who is. Don’t worry about cost, it will take less than 5 min to do the job.

 

[8388]

You *might* get off easy by using a pick or a small flat blade screw driver and tapping it in the counter clockwise direction on any rugged edges created when the bolt broke. Of course like every one said, let the oil penetrate first.

 

[Eagle85C4]

Same thing happened to me. I drilled out the entire bolt, it was metric so I used the next size down american. It removed the bolt without taking out the threads. Then retapped the bolt hole. Now the trick here is that the hole is drilled another inch longer then the stock bolt. So replace the bolt with one a 1/2 inch longer and you are back into good threads. Mine has not leaked in 2 years. Also the big problem here is the difference in metals, the steel bolt corrodes in the aluminum hole and makes a mess for trying to get it back out, use anti seize thread dressing and a lock washer to make sure it does not get loose.

 

[wx briefer]

There are two configurations (maybe more) of 'easy outs'. If the bolt is broken below the surface, one must drill hole. If a good bit of bolt thread is above the surface and just missing the head, one can use the 'easy out' that looks like a fluted socket inside to place over the bolt. Sears has 'em if you have prolems locating them.

 

[vette-dude]

If this is the bolt (s) that hold the thermostat hsg on, the way I repair them is to CAREFULLY drill out the old bolt, install a KEENSERT per the instructions, use a screw in stud, and then use a nut and lockwasher to bolt on the hsg. This way you never have to worry about the bolt breaking off again in the future. Here's a website for the KEENSERTS. I think you can find them locally at a bolt supply house. I like them as they lock into the aluminum hsg and are easier to install than a Heli-coil.

www.keensert.com

Randy

 

[vette-dude]

One thing I forgot to tell you is that you do not need the installation tool. The keys can be driven in with a flat piece of metal position on the two keys and tapped with a hammer. Cost of the item is around $4.00 depending on what size you would use. 5/16 x 18 should be about right.

Randy

 

[gray85]

I tried the two tools from Sears with no luck. I did get it out by drilling through the center of the bolt and then prying a small screw driver between the hole and screw.

I had to take off the manifold, since the manifold is off I will be getting a value job.

I do have a question on the condition of the lifters and value stems. The value stems have wear on the ends, and two of the lifters have some slight chipping on the edges.

I will start a new thread with pictures.


Thank you, for the help!!!