Broken Bolt

steven1213 · 03-17-2008, 08:08 AM

I broke the head of the 9/16" bolt which holds on the outlet for the radiator hose on top of the intake manifold. Does anybody have some pointers on the best way to extract it? What size easy out should I use and what size drill bit should I use to start it? I may end up having to re-tap with new threads if I cant get it out because the bolt is frozen in there pretty good. Any help is appreciated. Thanks-----------Steve

03chevy · 03-17-2008, 09:36 AM

use a 1/4 or smaller drill bit. here's a little trick that i have done acouple times, drill the center then take a butane torch heat it up not glowing red just hot and cool it down with wd40. do that a couple times. then use your easyout. what happens when doing that is you heat it up and wd40 cool it down is the heat will pull the wd in to loosen up the rust in the threads makeing it easy to take out.

75K30 · 03-17-2008, 09:51 AM

That is a problem that is pretty common, and believe it or not, can be a rather easy fix.
This area is refered to as the thermostat housing, and usually has a thick enough flange to expose plenty of bolt once the entire housing is removed.
Start by taking off the other bolt, (these 9/16" head bolts are a 3/8" thread), remove the entire t-stat housing. Next determine whether or not you can grab the exposed bolt with a pair of vice grips. You should have quite a bit of bolt exposed at this point.
Here comes the fun part. Aluminum, and cast iron intakes alike can be repaired in the same fashion.
You will need a heat source, like a propane torch, and a candle.
Lightly heat the intake where the bolt enters the threads. Heat this just hot enough to melt the candle when the candle is touched to the fastener. Apply the wax as low on the fastener as possible. You want the wax to enter the threaded portion of the intake. The wax will melt down into the threads and act as a lubricant, and provide a little help during bolt extraction.
While the intake is still warm enough to keep the wax in liquid form, you may then easily remove the bolt with the above mentioned vice grips.
If the bolt has broken flush with the intake, then an easy out will have to be used, so use the largest one possible, and still consider applying your new candle trick.
A little heat, and wax, can provide remarkable results for bolt extraction.
Good luck.

gmctrucks · 03-17-2008, 10:28 AM

A scented candle will make the job smell so much better.

steven1213 · 03-17-2008, 08:31 PM

Thanks guys I will try to find one of my wifes scented candles. I finally found a practical use for them. I never would have thought about heating the bolt up.

ryeja · 03-17-2008, 10:08 PM

Like 75k30 said "Lightly heat the intake where the bolt enters the threads." If you heat the bolt itself it could prove harder or even impossible to remove. Good idea with the candle, I've always heated the **** out of the part and struggled still to remove it. A little weasal **** (WD 40) will definatley help but don't introduce flame as you are spraying as you could end up replacing more than a thermostat bolt due to intense flames. Seen it done, NOT funny at the time.

75K30 · 03-17-2008, 10:59 PM

ryeja:
Thanks for picking me up there.
By all means only use a little heat (not red hot, propane probably wont get there anyway).
Heat only the area where the bolt meets the intake. Heat will actually make the metal expand, and this expansion is part of what you need to break the bolt free. If you apply heat to the bolt itself, you will expand the bolt, and it will become even more dfficult to remove.
WD-40 is pretty flammable stuff so be cautios when used around open flames. This can be a huge saftey issue, and this is why candle wax was suggested.
Again good luck.

03-17-2008, 08:08 AM	#1
steven1213 Full Member Join Date: Mar 2008 Posts: 16	Broken Bolt I broke the head of the 9/16" bolt which holds on the outlet for the radiator hose on top of the intake manifold. Does anybody have some pointers on the best way to extract it? What size easy out should I use and what size drill bit should I use to start it? I may end up having to re-tap with new threads if I cant get it out because the bolt is frozen in there pretty good. Any help is appreciated. Thanks-----------Steve

03-17-2008, 09:36 AM	#2
03chevy Senior Member Join Date: Dec 2006 Location: jax,fl Posts: 990	use a 1/4 or smaller drill bit. here's a little trick that i have done acouple times, drill the center then take a butane torch heat it up not glowing red just hot and cool it down with wd40. do that a couple times. then use your easyout. what happens when doing that is you heat it up and wd40 cool it down is the heat will pull the wd in to loosen up the rust in the threads makeing it easy to take out. __________________ A dirty mind is a terrible thing to waste!

03-17-2008, 08:31 PM	#5
steven1213 Full Member Join Date: Mar 2008 Posts: 16	Thanks Thanks guys I will try to find one of my wifes scented candles. I finally found a practical use for them. I never would have thought about heating the bolt up.

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03-17-2008, 09:51 AM	#3
75K30 Senior Member Join Date: Jul 2006 Posts: 2,507	That is a problem that is pretty common, and believe it or not, can be a rather easy fix. This area is refered to as the thermostat housing, and usually has a thick enough flange to expose plenty of bolt once the entire housing is removed. Start by taking off the other bolt, (these 9/16" head bolts are a 3/8" thread), remove the entire t-stat housing. Next determine whether or not you can grab the exposed bolt with a pair of vice grips. You should have quite a bit of bolt exposed at this point. Here comes the fun part. Aluminum, and cast iron intakes alike can be repaired in the same fashion. You will need a heat source, like a propane torch, and a candle. Lightly heat the intake where the bolt enters the threads. Heat this just hot enough to melt the candle when the candle is touched to the fastener. Apply the wax as low on the fastener as possible. You want the wax to enter the threaded portion of the intake. The wax will melt down into the threads and act as a lubricant, and provide a little help during bolt extraction. While the intake is still warm enough to keep the wax in liquid form, you may then easily remove the bolt with the above mentioned vice grips. If the bolt has broken flush with the intake, then an easy out will have to be used, so use the largest one possible, and still consider applying your new candle trick. A little heat, and wax, can provide remarkable results for bolt extraction. Good luck.

03-17-2008, 10:28 AM	#4
gmctrucks Senior Member Join Date: Nov 2006 Location: Houston,Texas Posts: 1,586	A scented candle will make the job smell so much better.

03-17-2008, 10:08 PM	#6
ryeja Senior Member Join Date: Apr 2007 Posts: 73	Like 75k30 said "Lightly heat the intake where the bolt enters the threads." If you heat the bolt itself it could prove harder or even impossible to remove. Good idea with the candle, I've always heated the ** out of the part and struggled still to remove it. A little weasal ** (WD 40) will definatley help but don't introduce flame as you are spraying as you could end up replacing more than a thermostat bolt due to intense flames. Seen it done, NOT funny at the time.

03-17-2008, 10:59 PM	#7
75K30 Senior Member Join Date: Jul 2006 Posts: 2,507	ryeja: Thanks for picking me up there. By all means only use a little heat (not red hot, propane probably wont get there anyway). Heat only the area where the bolt meets the intake. Heat will actually make the metal expand, and this expansion is part of what you need to break the bolt free. If you apply heat to the bolt itself, you will expand the bolt, and it will become even more dfficult to remove. WD-40 is pretty flammable stuff so be cautios when used around open flames. This can be a huge saftey issue, and this is why candle wax was suggested. Again good luck.