Vashon_Trawler
Guru
- Joined
- Jun 13, 2013
- Messages
- 598
- Location
- USA
- Vessel Name
- M/V Sherpa
- Vessel Make
- 24' Vashon Diesel Cruiser
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:
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: