Bolt head broke off!

As most projects go, a simple raw water pump change resulted in a huge project. My goal was to replace a leaky raw water pump. One bolt was particularly stubborn as a result of seawater corrosion. I soaked the bolts in penetrating oil and three of the four came out with ease. The "stubborn" bolt broke off at the head with what I consider minimal force and despite being careful.

Amazing that a little anti-seize compound on the threads would have prevented this from happening!

So, how did I get the bolt out?

Materials:

1) Angled drill (regular would not fit since the backside of the engine has little clearance with a bulkhead)

2) Center bits and left hand drill bit set (cobalt and machinist length)

3) Punch

After re-soaking the bolt in penetrating oil, I used a punch to create a dimple in the face of the broken bolt. The pump opening was sealed with tape to prevent shavings from entering. I then created a pilot hole with the center bit. I set the drill to reverse and drilled into the bolt with a left handed bit--I drilled slowly to avoid a broken bit. The bit was able to "bite" and back the bolt out.


I'm 5'10" and fortunately slender so I was able to contort myself to work behind the engine. None of this was fun!


There is a great video on youtube that describes the process:
Remove a broken bolt using a left handed drill bit - YouTube

Here is a before shot of the culprit:

Sounds like a similar process to the Easy Out tool.

Greetings.
Mr. B. Indeed similar BUT the advantage, since you're using a left hand drill, is a very good chance the broken stud will just back out with the process of drilling. If it doesn't back out, you've got your hole for the Easy-out.

RT Firefly said:

Greetings.
Mr. B. Indeed similar BUT the advantage, since you're using a left hand drill, is a very good chance the broken stud will just back out with the process of drilling. If it doesn't back out, you've got your hole for the Easy-out.

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Exactly, RT. The Easy Out was a last resort. The thought of one breaking frightened me. The left hand bit backed the stud out far enough to grab with vice grips.

My favorite trick for breaking frozen threads loose is to heat the surrounding metal. Obviously that would have been hard to do in this situation.

Has anybody tried this stuff?
"A unique formula that immediately drops the temperature of the area in direct contact with the spray. The freezing effect cracks rusted surfaces, allowing Freeze-Off® to reach deeper & work more effectively than other penetrants. Low VOC Formula."

Had the identical incident happen with my pump and I swear Cat must use triple hardened steel bolts. Despite liberal does of penetrating oil and banging it to loosen mine also broke, in my case the drill bit did not run true and it completely ruined the threaded hole on the back side leaving a small chunk of the bolt still embedded. I ended up drilling the hole larger & simply through bolting it using a nut & lock washer on the back. I now dread taking anything apart on my engines but when I do, every bolt gets never seize.

I may pick up a can of the stuff Hopcar mentions & try it in the future. A micro set of acetylene torches would be a blessing to have aboard if they made such a thing.

Captk

Did your engines get sprayed with salt water?
You might start spraying all bolts with wd 40 from time to time.

Capt Kangeroo said:

. . . . A micro set of acetylene torches would be a blessing to have aboard if they made such a thing.

Click to expand...

They do, and, to my surprise, Harbor Freight now sells them! I have one purchased some years ago (not from HF). Beautifully made - need their own regualtors though, so not a cheap package.

Greetings,
Not expensive....relatively. Mag Torch Bernzomatic Worthington Braze Weld Cut Kit Oxygen Map Gas Cylinder | eBay

Broken head bolt

I had a head bolt snap off when torquing a head on an old 6 cylinder engine on our boat. It was the last bolt to be torqued on a 3 sequence torque job. Bang snapped off flush. I was in a remote location in the Philippines and no access to a reverse drill or easy out. What we did was weld a stud to the exposed bolt head and then was able to back it out with a wrench. Then we had to have a bolt machined to fit as we could not find a bolt of the same side. This time I didn't let my mechanics over torque the bolts. They seem to think more is better.

Bayview, your pretty sharp, that's exactly what happened. The PO must have decided it was just fine having the leaky raw water pump spray salt water all over the front of the engine for months. The pic shows the extent of this completely unnecessary damage, the belt guard (missing in the pic) along with the pump, crank & Alt pulley's were completely destroyed. With the exception of replacing the crank pulley, I have it all looking sparkling new now but it was a lot of work. Like Vashon, I also carry cobalt bits now.



RT, I had one of those once, they do work but as I recall the oxygen only lasts about 8 minutes. Still a nice cheap compact set that might suffice for emergencies.

Capt Kangeroo said:

Had the identical incident happen with my pump and I swear Cat must use triple hardened steel bolts. Despite liberal does of penetrating oil and banging it to loosen mine also broke, in my case the drill bit did not run true and it completely ruined the threaded hole on the back side leaving a small chunk of the bolt still embedded. I ended up drilling the hole larger & simply through bolting it using a nut & lock washer on the back..

Click to expand...

Helicoil would be an alternative, you were fortunate having access to through bolt.