Getting the remains of a bolt out of aluminium?

Iamzod

Iamzod

Iamzod

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I have been stripping & rebuilding an engine these last few weeks however I have managed to shear the head clean off a nut that attaches the water pump to the timing chain cover.

I am left with about 8-9 mm of the bolt protruding & was considering welding a nut onto the end of it in order to remove it but I've been told the heat will damage the aluminium, will this be the case or will I likely be ok?

Any help greatly appreciated!
 
I'm not certain but if its an alu block rather than a thin bit of plate I wouldn't have thought it'd be much of an issue.

Can't cut a slot and knock it round?
 
Got a picture?

The way it sounds, it shouldn't be under any strain so a set of mole-grips would do it but im sure you have already tried that so im finding it hard to picture the situation.
 
Is there enough thread to get 2 nuts on there and tighten them up against each other so that they can then be used to undo the whole thing?
 
Welding a nut on should be fine provided you aren't welding right up against the alloy (and with 9mm sticking out you won't be). Aluminium is a good heat conductor so you'd have to put a lot of heat into a big lump like an engine block to cause local melting.
 
Last edited:
Finners said:
Got a picture?

The way it sounds, it shouldn't be under any strain so a set of mole-grips would do it but im sure you have already tried that so im finding it hard to picture the situation.
Click to expand...

It snapped for a reason!

The reason is likely to be that corrosion has formed a very effective "Glue" sticking the steel bolt to the alloy threads.

Heat up the remains of the bolt (Carefully) with a blow torch (or ideally with oxy and a small tip), spray with WD40 to cool it down and then unscrew by hand! ;)
 
The heat will be a good thing as it helps break the corrosion. The higher thermal expansion of aluminium works in your favour. Make sure the protruding bit of stud is cleaned back to bright metal and use lots of power for the weld. You need to ensure plenty of weld penetration or the but will just spin off. Also, use the biggest but that is practical as it'll be easier to get the weld in.
 
if it's a steel bolt and an alu block I really feel for you - when they oxidise they effectively cold weld to each other. On my old car there was a pinch bolt (steel) which went into an alu block and it would NOT come out - even took it to a garage. Drilling it out would have been the only option. good luck, you're going to need it

B@
 
let some WD40 or similar soak into the threads then get a pair of molegrips on it and see if you can ease it out.

With a decent section of the bolt sticking out you've got a fighting chance that way, it'd be a lot worse if it had snapped off flush.
 
I had my towing eye snapped off at the stem, flush with the screw hole.

I had to drill a hole into the remaining toweye stem, and then hit a flat head screwdriver into the hole, the widest bit of which was narrower that the hole I drilled, in order to give it as much grip as possible.

Came out really easily when I tried that.
 
Assuming the remains of the bolt are no longer in tension, you could try shock loading the end of it (CAREFULLY) using an SDS drill in chisel mode, thus breaking down the oxidisation in the thread, then using any number of the above suggestions to undo it.
 
danza said:
Assuming the remains of the bolt are no longer in tension, you could try shock loading the end of it (CAREFULLY) using an SDS drill in chisel mode, thus breaking down the oxidisation in the thread, then using any number of the above suggestions to undo it.
Click to expand...

Could try drill in reverse? Actually chuck might undo:p
 
It's out. I couldn't find a steel nut in the garage that was the right size & I didn't need so I got a stainless steel one that was slightly too large to use as a spacer so I wasn't too close to the Aluminium.

I then welded loads of blobs of weld to the top to give the mole grips something to hold onto and it came straight out.

This is what I was working on-

 
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