The old " I broke bolts off in the head question"

[IamCanadian]

Decided to check the thermostat in my 1966 Chrysler 50, All 3 screws broke off in the head. Any tips on how to get them out? or should I just drill out a size larger and use bigger bolts? keep in mind they are very very weak and twisted off like they had been made out of lead.

Here is a pic.

 

[pnwboat]

Re: The old " I broke bolts off in the head question"

Try soaking the area with penetrating oil overnight. Looks like you may be able to get a pair of vice grips on a couple of the bolts. You can also try gently heating up the area with a propane torch and gently tapping on the bolts. If all else fail, then yes drill out and tap.

 

[glenn property of pam]

Re: The old " I broke bolts off in the head question"

if you have to drill take your time and grind the heads flat then dot punch and if you have a dremel use that to start the pilot hole started. A napa square easy out is better than a cheap swirly type because breaking a easy out makes a broken bolt look like childs play.

 

[BonairII]

Re: The old " I broke bolts off in the head question"

If possible.....cut a notch in the broken bolt and use a flathead screwdriver to turn it out(after heating and/or soaking with PB blaster).

 

[IamCanadian]

Re: The old " I broke bolts off in the head question"

I may remove the head and do the job in a drill press, Wouldnt mind replacing the head gasket anyway for some added piece of mind for the season.

 

[jerryjerry05]

Re: The old " I broke bolts off in the head question"

You just broke off 3 little ones.
Make sure the head bolts are free before you break them too.
They are only tightened with less than 20 # tourqe.
I had to work almost 4 hours removing 3 bolts on a 85 block.
It needed a propane torch,PB Blaster,WD-40 and a hammer.
If the bolt doesn't loosen easily by hand on the first try.STOP and start the spray and then heat and tap the screw and then repeat.
Then turn in small bites.1/16th turns.

I had trouble with the thermo housing too.
Almost 3 hours to loosen 3 screws.

Moral of the story??? Just go slow and don't strong arm it.

 

[gm280]

Re: The old " I broke bolts off in the head question"

DON'T drill and tap to a larger size. If you have to drill those broken bolts out, start with a very small drill bit and work your way up a size at a time until you can work the remains out with an awl or scribe or something like that. Then tap the existing holes with the correct type tap before going back with new bolts... You only drill and tap to larger sizes when the existing threads are to far gone or stripped...

 

[pnwboat]

Re: The old " I broke bolts off in the head question"

If you have access to a TIG welder you can also weld a nut to the broken stud and remove it with a regular wrench. The heat from welding helps break the bond or corrosion. This is an old welder's trick that has been used for many years. You can also use a MIG welder but, TIG controls the heat better.

Another "Frozen" Fastener Extraction - WeldingWeb? - Welding forum for pros and enthusiasts

 

[belairbrian]

Re: The old " I broke bolts off in the head question"

If you take the head off, just take it to a machinist and have him do it. Sometimes, especially with old parts, it's best to let a pro handle it.

 

[Grub54891]

Re: The old " I broke bolts off in the head question"

Sometimes drilling with a left handed bit will screw em right out,if not to corroded....

 

[IamCanadian]

Re: The old " I broke bolts off in the head question"

I am a welder by trade, I will just take my time with heat and pb blaster, there is enough material to grab hold with a pair of grips.

I hope to fire it up this weekend and star on my transom.

 

[jerryjerry05]

Re: The old " I broke bolts off in the head question"

When I say heat, I mean a small propane torch.
The cutting torch I have even turned down can be too much heat.

 

[3rdtimesthecharm]

Re: The old " I broke bolts off in the head question"

I`ve had good luck doing this too.

Sometimes drilling with a left handed bit will screw em right out,if not to corroded....

 

[johnbottsr]

Re: The old " I broke bolts off in the head question"

Left-handed bit after all the soaking and heating.
If it doesn't come out then, at least you have a hole for the EZ out.