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Discussion Starter #1
Anyone else had theirs break off? I have 4 broken in total, might have to get them drilled out :(
 

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Yeah a few were already sheared on mine, I drilled out and re-tapped two successfully by hand, the third I went off center and had to go up a size. Obviously the cast iron is much softer than the bolt you are drilling so a mistake quickly goes bad. The key is patience and to dremel the top of the remnants of the bolt to get a flat or slightly dished surface, then a clean centre punch to keep the drill centred. If you start to go off centre sometimes you can rescue it by using a small grinding stone or carbide bur to open the hole in the direction you want.
 

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I had the same issue and got annoyed trying to drill them back out.

So I ended up just grinding off the remaing material then heat wrapped the manifold instead :p
 

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the manifold ideally needs some heat to expand the thread, then with a nut welded to the broken bolt it should come out.

drilling is tricky as if you don't get dead centre it can become a knightmare.


that's how I do it anyways, I have a mag drill for removing broken bolts from my machines but its last resort that I use it.
 

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I've never had much luck with welding a nut on, tried it a few times. If you are patient and have the time on your hands drilling works ok but there is room for error and there are places were a mistake would scrap an expensive part and I'd think twice before drilling that sort of thing myself.
just welding a nut will hardly ever work as the threads are seized/rusted together, with enough heat so the outside area of the thread is red hot it will expand and release the thread. ive done it literally 100s of times on my caterpillar dozers.

if a small hole is drilled right through the bolt that can help aswell as it will release any pressure the bolt thread has on the outside thread.

ive recently changed the turbine housing on my gt40 turbo and without heating the housing the bolts wouldn't of come out, ive had 2 garrett t6 turbos in the past I had to cut the heads of the bolts and then drill them out and it wasn't an enjoyable job !
 

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Discussion Starter #9
I tried to tap and drill but burnt the drill bit out lol. I had to take it to my local engineering shop and they managed to sort it out. The Tomei manifolds are sexy and tempting, but it is a big shame about them prone to cracking. I will stay with cast ones.
 
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