Snapped Head Bolt - Help!!

[fomoco_44]

Hi All,

New to the site and new to Zed ownership(not really the owner, just an amateur mechanic in an amateur car club)

Anywayz, down to the problem at hand. Its a mates car I'm working on (76 2+2 260z) with a leaking head gasket, which looks like it s been a problem for a while. I wen't to take the head off last night and removed all but three of the bolts which just didn't want to budge. Thought i would take another stab at it, as the others were tight with corrosion but eventually gave, and the head of the bolt sheared off!!

After many expletives I inspected the remains to discover why it was so tight....coolant has seeped into the bolt hole, dried and virtually welded the bolt to the head. I suspect this is the case with the other 2 bolts(evidence of fluid weeping down the bolck near these bolts).

My plan of attack from here is to heat the remaining bolts with a portable blowtorch, bit of shock therapy with a lump hammer, and sacrifice a small animal to the Datsun Gods. Once I can get the other bolts off I'm hopping I can lift the head up and over the snapped bolt, and then have a better chance of removing it.

Does anyone else out there have any other ideas\hints\advice for me?...anyone had the same problem 

[260Coupe]

Spark erosion may be the sure fire way to get the head bolt out without damaging the cylinder head

[fomoco_44]

Hey 260Coupe,

Forgive my ignorance, but whats spark erosion?

[260Coupe]

And electric charge (ie a high current spark) is used to erode away the broken bolt without damaging the surrounding thread.....much like a big spark plug firing a high current spark which zaps away the metal......many engineering shops have this facility.

cheers

Alan

[PZG302]

Easy out, hope that's the right spelling, and then Helicoil works fine, my first L28 had a couple of bolts let go trying to get the head off and once done never a problem for another 4 seasons of fairly hard racing.

[fomoco_44]

Ok, thanks guys.....had never heard of spark erosion working on a thread before. Our old toolroom had one for making dies and jigs, but it was a pretty big machine.

Hopefully I can get the other two out without snapping them, so then i only have to deal with one and can leave the block in place.

I am still a bit wary of using an easy-out on the stud....bit worried that if its tight enough to snap the head of a high tensile bolt an easy-out might not have a chance. Glad you reminded me of the Heli-coil...completely forgot they existed!!

[pauly_adams]

when you get the head off try soaking the bolt in crc or wd 40, then get one big pair of vicegrips and try to undo the bolt worked for me before but cant say it will work for you but safest option to start with

 

cheers pauly

[Zedman240®]

A good friend of mine (ex fitter) told me the best fluid for releasing frozen studs of all things is brake fluid! He recently removed 2 broken exhaust flange studs for me using good ol dot 4. He swears by it.

[fomoco_44]

Just snapped the 2nd bolt off!!....one left to go now!. Heating helped budge is a couple of turns but then it just snapped.

I am thinking I'll snap  off the 3rd one and try to get the head off....then I can get to the threads with some brake fluid and much aggression.

Thanks for your help guys

[Dingo Dave]

I Have had this problem. I used an oxy to heat up the bolt and then they turn out but you need to be pacient and turn it out turn it in, turn it out and in for a few times because you should have rust right up the bolt. With the ones that are broken off. Use some sort of jack or hydrolic lift to move the head up evenly. You can damage the head more by twisting it or lifting it unevenly.

My first time I did it I used a bottle jack on one side move it a tiny amount, release the pressure. Apply spacers on the other side. Jack it a little more. Dont do to much though because you are going to extrude the aliminium head and it will make a lip around the hole and this isnt good. Lubricants or hydrolic oils are good to use. Find out where the bolt has broken off though because they step down part way down the bolt and this can cause damage when taking the head off. If needed drill a little. Then heat the bolts up and use multy grips to turn them out while still hot.

[.]

So what was the outcome on this? Any suggestions how best to remove a snapped head bolt. I have one snapped in the block. It is flush with the deck of the block so I can't use multigrips.

 

Should I try an ezy out?

Should I just give it to a professional?

Should I ditch the block and move on to my spare?

[Scoota G]

Place a dynabolt sleeve around it and then drill small holes across the bolt  to make a slot for a screwdriver, vacuum out and use a square shaft screwdriver that can fit an adjustable wrench. You can put a lot of pressure on it downwards.

 

Just realised this is a 3 year old thread. . . Yikes!

[.]

Just realised this is a 3 year old thread. . . Yikes!

 

Yeah but I thought that would be better than starting a brand new one and having people say ...go check such and such thread.

[C.A.R.]

Greg, go buy yourself a set of splined Ezy-Out's.

Simply drill a hole in the top of the stud, hammer in & then undo.

[Zedman240®]

Avoid the cheap ezy out's...or else you will have to buy another ezy out to remove the other ezy out to remove the original bolt! You can always drill as much of the original bolt out until there is very little of it left then re tap the hole. Might be very hard since the head bolts are high tensile..Oh, try some brake fluid on it to help remove it..

[lightmaster240z]

Rather than wd40 use penertrine it work better and let it sit over night.

[peter mc]

good advice there spamaster ,  in the work shop we have left hand drill bits for this problem and they work like no other product i have seen  just drill the hole with it and most times it removes the stud

[Patch]

An Old mate of mine who does lots with older cars swears by using Methylated Spirits to free up locked up rust, I tried it the first time on freeing up my motor that has been sitting for 10 years, soaked it over night down the plug holes,  and got movement the next day with a screw driver on the fan pulley back and forwards, yet I could not get movement with WD40, Soaked it again for another day and no problems to turn over by fan complete turns. I filled it up again and a week later spun it with the start motor, haven't started it yet got to sort out spark and fuel issues.

 

He said he has found it the best as it eats away the rust.

[.]

Excellent suggestions, and great timing too. At least I have some things I can try over the weekend. I will advise on the result.