How To Remove Shreaded Bolts From The Block

[ifcho 0]

Hi,

 

Yesterday I was removing the head from one 1.9 engine, and someone had done the headbolts really tight...

and two of them shreded and parts of the bolts are now in the block.

 

Is there a way to remove them? I'm at my office this weekend and I cannot take a look from the downside of the engine, but it keeps me buzzing.

Are the bolts protruding from the block? If yes, maybe I can use some extractor bits and remove them from the other side?

 

Any ideas?

[brianthemagical 1]

with reet difficulty i think is the best bet. they snap because they are siezed t the bottom. the only way i can think of is tp get it drilled out but as the bolt is vert hard and the block isn't, you need to be very careful and ideally use a drill press.

[applemobile 0]

i would take drilling as a last option. keep them soaked in wd40, and try a stud extractor or some mole grips. you might just get lucky.

[GLPoomobile 958]

But substitute WD40 for something like Plusgas.

[ifcho 0]

Plusgas is gas for lamps right? If so I think I have a bottle at home and I can soak them with it tonight. However, I'm not very keen on using extractors as if they break in there won't be many more options.

 

I asked a friend mechanic, and he said that the method is to to drill the bolt with 4mm bit, then 6 and finally 8mm. Then use a left tap to get the bolt out, from the heat it should go out easily, alternatively a left drill bit should also do the job...

If this fails, then drill the bolt again to 10mm and again with a tap, but this time the drilling must be done on column drill (I'm not sure if that's how you call them...) as the bolts are 11mm...

[Ryan 99]

No, Plusgas is a spray lubricant. It does a FAR better job than WD40 though. Once you've tried it you'll never buy WD40 ever again.

[Edp 67 3 Cars]

This happened to me when i stripped my head.

 

A company from Sutton came to my house and heli-coiled the bolt for £90. Good value i think.

[applemobile 0]

you could probably buy a helicoil kit, and do it your self for under £20. still involves you having to drill it out tho.

[JimLad 1]

You could try welding a nut to the broken studs. The heat from welding the nut on often frees off the threads.

[B1ack_Mi16 67]

Had the same problem once. As the bolt usually breaks a bit into the block you can't really weld anythign to it.

 

Just drilling it out might be hard as it will not be easy to make the drill hit spot on centre of the hole.

 

I took the block to a machineshop and they milled it out, then helicoiled it afterwards.

[nick 3]

This happened to me when i stripped my head.

 

A company from Sutton came to my house and heli-coiled the bolt for £90. Good value i think.

 

I don't £90 will cover a trip to Bulgaria...!

[ifcho 0]

heh, absolutely, for 90 pounds I can just buy a new engine

[ginjaspeed 0]

Last time i had this happen to me, the bolts sheared above the block, so were reletively easy to remove.

[Guest ae86clyde]

This happened to my mi16 engine when i pulled the head off, your better taking it to a professional because it very easy to damaged the block.

 

I took mine to a engineer who lived close to me and he drilled out both my broken bolts and helicoiled them for £20 which was an absolute bargain!!!

[ALEX 98 1 Cars]

The threads are exposed at the bottom and go rusty. When you remove them after 10 years of rust and grime the dirt gets jammed in the holes and locks up the bolt causing it to snap!

If you screw the broken stud down and out through the bottom in theory it should work. Depending how far down the bolt snapped It should be possible, if you can't get the stud out through the opening at the bottom (i.e it's too long), at least you could clean the exposed threads up to remove it from the top.

You'll need a reverse extractor this way though, or you could try and drill and tap it to about M8 and use a HTS. bolt with a couple of nuts a few threads up from the end!.

Not tried this method myself, but I did think of it after trying to remove a few with an expensive extractor, which snapped causing more grief!

 

Edit: We managed to drill the hole for the extractor perfect centre, it wasn't easy and a centre punch is a must.

Also it's only possible if the bolt sheared flat! If you're unlucky and it hasn't I can imagine it impossible with a hand drill to get the hole central. The block will will need clamping down on a pillar drill.

Edited February 4, 2008 by ALEX

[Rob_the_Sparky 9]

Oh and of all reports I've heard that the left hand thread extractor are a waste of time. They tend to snap off leaving a lump of hardend steel in the broken bolt, virtually impossible to drill.

 

Also the engine is canted and aluminium so drilling is very hard to do right. Generally easier to get an engine unless you have a good reason to preserve the one you hgave.

[Tom Fenton 1,526]

I've cured this in the past by making a steel plate to pick up on a couple of the OK head bolts. I then borrowed a magnetic stand mounted drill press, usually used for drilling girders etc. By positioning this on the steel plate I was able to drill the bust stud out totally square to the block face. I then helicoiled the hole as the alloy was chewed up. The thread is 11x1.0, you will probably find you need to use 2 inserts one on top of the other to get enough thread engagement to be as it would be as standard. I now always use anti seize on the bolts when working on XU alloy engines.

[jeremy 68]

When I sheered a head bolt in my 8 valve I ended up taking the engine out, this had to be done as access from both above and below was just to tight to enable me enough. I then used a ring spanner over thend of the bolt protruding from the bottom of the block and pussed it hard down against what little bolt that was accessible and then turning the bolt a fraction of a turn. I also drilled small holes perpendicular through the bolt and inserted a small piece of metal (something like a watchmakers screwdriver through it and turned the bolt too. Both methods were slow. To give you an idea it took me six hours before it popped out

[ifcho 0]

I was thinking of drilling small holes in the part of the bolt showing from the bottom as well, I may give it a try these days when I have some more time for this.

[Beastie 1]

Oh and of all reports I've heard that the left hand thread extractor are a waste of time. They tend to snap off leaving a lump of hardend steel in the broken bolt, virtually impossible to drill.

 

The eponymous term for these are easyouts The Ison bicycle tool catalogue always used to comment that this is a misnomer because they are far from easy and they never get it out

 

Removing the remains of High tensile bolts from aluminium with any degree of success is a skilled job. If you don't already posess those skills then I would highly recommend taking the complete assembly to a professional whose skill will be worth every penny!