Broken Bolt Blues

[Island Fish Lifter]

if you are at a point of no return, make a drill guide to fit inside the hole so that you can drill a perfectly centered hole. If you can do that, then you can gradually increase the size of your drill bits until there is nothing left of the stud then run a tap through the hole. This can be done, but you will need good quality, sharp drill bits. Make sure you drill them at low rpm's and take your time.

 

[Island Fish Lifter]

from what I can see, someone has had a similar problem in the past as the remaining bolts are imperial stainless, not OEM metric.

 

[Percy Stipec]

I'm sorta thinking the same thing as you, there are 4 bolts holding it in and 3 broken bolts. The two stainless bolts are replacements for the two that did not break when I removed them. The other two I haven't touched but they look as if at least 1 will surely break if I try taking them out. I haven't tried running the motor yet because I am also waiting on a starter solenoid that caught on fire last month. I'm thinking if the manifold does not leak I will not try to remove the bolts that will likely break but it would be nice to get out the broken ones. The only problem with this is that I cannot replace the internal zinc anodes. These bolts should have been stainless from day one I think. Thanks for the responses.

 

[Wild Bill]

Looking at the housing I would measure with a vernier caliper and determine if the bolts are above or even flush with the casting surface. Work real hard at not breaking the other two, all depends if you can sense bolt movement and not just how would you say bolt failure movement. If the stud is even a little above the casting put a nut around it and weld it to what's left. Quite often the heat will loosen up some of the corrosion. I let it cool and lube the crap out of it. Back and forth, stop to stop till wrench travel gets larger and larger. Lots of lube.
If all else fails, a perfectly cantered drill bit, start with a pilot hole and drill through bolt. Then determine how close to centre you are. Take a drill bit same size or just smaller than smallest diametr of threads and drill through bolt. Depending on how centered you are you can see the threads breaking through the bolt. Sometimes rocking the same drill bit taking extra material from the side you still see solid thread will work or use a carbide burr till you can see thread lines through the steel. Quit often you can pick out one end and pull what's left out as it spirals out of the threads.
Then helicoil if necessary.

 

[Percy Stipec]

Alright ordered some carbide burrs on amazon scheduled to arrive on Thursday and got a dremel. Unfortunately there isn't enough sticking out to weld on a nut. The plan is use dremel/drillbit to get the bolts out. The carbide burrs should be able to go through the broken EZ out. I'll update when I get a burr on those bolts