Broken Head Bolts Solution

TheShadow619 said:

So I have seen several posts all over about GM broken TTY bolts. I have been an auto mechanic for 20 years, most as private fleet mechanic. This is the first time I have encountered this problem with head bolts. I took the head off of a 2006 4.2 L6 because of bad valves. I tried the hammer and punch, rattling the bolts with an air gun, tightening a bit then backing off, working the bolt back and forth, etc etc... nothing worked. I broke 11 out of the 14 bolts.

So here's how I removed them. You don't need a $400 extractor set.

I started by filling each bolt hole with PB Blaster penetrating oil for 2 days. Then I got a Blue Point E1020 extractor set ($125). It worked great on the one bolt I used it on. I used the centering sleeves that help center the drill bit on the bolt on every bolt. The sleeve keeps you from accidentally messing up the block. I had to put a single layer of electrical tape around the sleeve to make it tight in the hole in the block. But this set doesn't have left hand drill bits. Then I discovered that long left hand bits are hard to find. So I picked up a set at Harbor Freight for $9 (Item 61686). I figured they only need to last for a few drills anyways (but I used cutting oil, and the bit stayed very sharp for all 10 bolts). I also picked up a $10 screw extractor set(Item 95530). I used a cordless electric drill, the rear 4 bolts will require a right angle drill. The left handed bit caught and removed 8 bolts without using an extractor. The 2 very rear bolts required some help. I drilled the bolts with the 3/16 left hand bit, then used one of the HF screw removers with a 3/8 ratchet. The screw remover caught the bolt and spun it right out without having to drill very deep.
All the bolts came out clean. The holes look great, and I expect no stripping problems going back together. I hope this info helps someone out there. Good luck. Take it slow, lots of lubricant. And keep the holes clean of cuttings while trying to remove the bolt.

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Ravalli Surfer said:

I've always made it a rule to not panic when trying to remove broken bolts - especially the ones that require a right-handed drill.

Left-handed drill bits are sometimes all you need and if they are too short --- there's no rule that says you cannot braze extensions on them. I've brazed multiple extensions, collectively over 3 feet long on special projects involving tilt-up slabs, and never had a braze fail nor lose as bit in the slab either. This was with using a rotary hammer drill ... so too there's that success.

Start small ... use a hardened drill guide if you can, and if possible - use a punch to help start the point .

And about drill bits .. Kennedy Cobalt bits have always served me well ... but even a simple VS or Moly bradpoint bit is a LOT better that no-name or HF tin plated Chinesium drills.

BIG RULE TIME ----> take time to make a plan ---> take time to run your plan.

Broken off bits inside a bolt or stud can be decimating --- but there ARE services ($$$$) that can remove broken taps and drill bits.​

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