Broken Bolt Extraction-Ideas

explorerlyon

explorerlyon

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I need to remove a broken bolt from an aluminum engine block. Hoping some of you may have some ideas. Or, if someone can machine an extraction tool for me, I would be glad to pay. I read on the internet someone else had the same broken bolt as me. They machined a sleeve for the hole and used a reverse drill bit to extract the broken bolt. The need for the sleeve was to center the reverse bit down a blind hole. With a depth of 2.5", the sleeve also supports (or was attached to) the drill bit.

Bolt is broken off 2.5" deep.

Here is the broken bolt. It's about a 1/4" shaft.
Water Pump Bolt.jpg



The broken bolt end is recessed 2.5" down this hole. (The larger pipes to the left can be pushed out of the way)

Location.jpg


More details: The location is on the front of the block. Six bolts attach the water pump. Four bolts thread directly into the timing chain cover (threads visible in the picture). Two of the bolts pass through the timing chain cover and thread into the block. This is on a 2003 BMW X5 v8 ( 4.4). The alternative is removing the timing chain covers. The cost of removing the covers is more than the car is worth. I want to at least try and extract the bolt before junking the car.
 
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I'd just get a brass pipe to fit the hole the depth of the cover then drill it with a reverse drill. You can get any size brass pipe online or at a hobby shop. Wrap the bit in masking tape until the pipe fits well, if you want to go crazy you can use a paper wrap on the bit and then a drop of superglue to attach the pipe to the bit. The superglue will soak into the paper and make a nice plastic/paper bushing. That bolt looks pretty long but obviously if somebody else has done it there's hope.
 
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pagrey said:
I'd just get a brass pipe to fit the hole the depth of the cover then drill it with a reverse drill. You can get any size brass pipe online or at a hobby shop. Wrap the bit in masking tape until the pipe fits well, if you want to go crazy you can use a paper wrap on the bit and then a drop of superglue to attach the pipe to the bit. The superglue will soak into the paper and make a nice plastic/paper bushing. That bolt looks pretty long but obviously if somebody else has done it there's hope.
Click to expand...
Very helpful, thank you. Trying to visualize the superglue suggestion......are you saying to glue the brass pipe to the bit? So the entire assembly spins inside the hole?
Also, any tips on how to extend a reverse drill bit? All the reverse bits I can find are about 1" too short. I need a reverse bit that is at least 3.5" long (preferably 4" long) between 1/8"-7/32". I can find extended-length normal bits, but not reverse bits.
 
explorerlyon said:
I need to remove a broken bolt from an aluminum engine block. Hoping some of you may have some ideas. Or, if someone can machine an extraction tool for me, I would be glad to pay. I read on the internet someone else had the same broken bolt as me. They machined a sleeve for the hole and used a reverse drill bit to extract the broken bolt. The need for the sleeve was to center the reverse bit down a blind hole. With a depth of 2.5", the sleeve also supports (or was attached to) the drill bit.

Bolt is broken off 2.5" deep.

Here is the broken bolt. It's about a 1/4" shaft.
View attachment 314117


The broken bolt end is recessed 2.5" down this hole. (The larger pipes to the left can be pushed out of the way)

View attachment 314118

More details: The location is on the front of the block. Six bolts attach the water pump. Four bolts thread directly into the timing chain cover (threads visible in the picture). Two of the bolts pass through the timing chain cover and thread into the block. This is on a 2003 BMW X5 v8 ( 4.4). The alternative is removing the timing chain covers. The cost of removing the covers is more than the car is worth. I want to at least try and extract the bolt before junking the car.
Click to expand...
Get an accurate measurement of the ID of the hole and then use that to check pieces of steel fuel and brake line in the assortments parts stores have. Use that sleeve to drill. Don't bother with that left hand stuff, just drill with a good bit and then use the square corner extractor. The reason folks break them off is they tip them over sideways when they turn them. Don't do that.
 
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mrblaine said:
Get an accurate measurement of the ID of the hole and then use that to check pieces of steel fuel and brake line in the assortments parts stores have. Use that sleeve to drill. Don't bother with that left hand stuff, just drill with a good bit and then use the square corner extractor. The reason folks break them off is they tip them over sideways when they turn them. Don't do that.
Click to expand...
That makes sense. I am assuming with a bolt diameter of only 1/4" I want to drill about half of that diameter, so 1/8". My search for square extractors in small sizes, like 1/8", are all short. Do you think welding a rod to the end of a square corner extractor to make it longer (like 3.5") will work? Same issue I am finding with reverse drill bits, none are long enough to go down the hole.
 
It might take less force to use a reverse bit than to use an extractor, if you can weld something like that together you might consider the drill first. If either one breaks while you are using it you're in a much worse situation overall with a hardened thing in there. I might drill a small hole and get a slightly bigger fastener with slots cut in the end like a tap and get a little bite on it to see if it just rolls out. Just something to try first that doesn't involve making the situation worse quickly. Worst case on that you are ready to try anything else suggested, just go easy on the smaller bolt.
 
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