Aaaaargh... broke a bolt

franksm

So there I was, bolting the thermostat head back onto the engine and *clank* the head of the bolt falls onto the ground. There's nothing left of the bolt outside of the head, so I need to extract it with a special bit.

Unfortunately when I drilled into it to make room for a screw/extractor bit, the drill bit broke inside the bolt. Double-aaaargh.

Is there a special drill bit I can use to drill out the remains of the broken bit ? I'm using standard HSS bits and I'm rapidly building up a nice collection of broken drill bits.

The only good thing is: it's at the front of the engine, so there's plenty of room for working on it.

Any ideas ? Or anyone know any mobile mechanics in the Clonsilla direction ?

andyj22

Uh oh. Sounds like the bolt simply siezed up in the hole. They do sell bolt extractor kits for broken bolts, but I'm not sure it'll work on a siezed up bolt.

You might have to carefully drill it out- inching up from a small size to one that is just under the minor diameter of the bolt hole. Then clean out the remaining pieces and debris with a good thread chaser.

Adam

corktina

i trhink you need a special hardened bit to drill out a bolt...they usually come with the extractor kits i think.....can you weld a nut on to the broken bolt and get it out that way?

franksm

If I could weld

Going to try to get a "proper" centre-punch and attempt to shatter the drill-bit remains. A lad on octane.ie mentioned getting proper tools from an engineering supplier - need to figure out who/what that is. I think I cross-threaded the bolt, and that's what caused the prob, so I'll need to retap it too.

Also mentioned by someone else was using a cobalt-tipped drill-bit, which apparently is a masonry or concrete drill-bit

MercMad

This has happened to me on several occasions !

You need a hardened bit definitely, you may be able to pick the remains of the drill out, but using standard drill bits, or masonry is a waste of time.

It would be better if you could get some heat on there, from a torch, so soften the remainder of the bolt. Welding would be the quickest and easiest by far, maybe you could hire or borrow a welder locally, they are portable after all !

Howvere one of the things you MUST buy is a can of PlusGas. This is the best penetrating fluid you can buy, used on aircraft and never let me down. Halfords do it as do Radionics.ie. Also treat yourself to some Easyouts.

Both of these are what should be in your toolkit at all times because if you work on cars this will happen sooner or later.

Good luck !

franksm

Thanks dude

Shopping list:

centre punches
http://www.radionics.ie/cgi-bin/bv/rswww/searchBrowseAction.do?Nr=AND(avl%3aie,searchDiscon_ie%3aN)&Ntx=mode%20matchpartial&N=4294954481&in_dim_search=1&name=SiteStandard&forwardingPage=line&R=3814896&callingPage=/jsp/search/search.jsp&BV_SessionID=@@@@0046599084.1175162949@@@@&BV_EngineID=ccdiaddkhmjdkfmcefeceeldgondhgj.0&cacheID=ieie


PlusGas
http://www.radionics.ie/cgi-bin/bv/rswww/searchBrowseAction.do?D=plusgas&Nr=AND%28avl%3aie%2csearchDiscon_ie%3aN%29&Ntk=I18NAll&Nty=1&Ntt=plusgas&Dx=mode%20matchpartial&Ntx=mode%20matchpartial&N=0&name=SiteStandard&forwardingPage=line&R=0691117&callingPage=/jsp/search/search.jsp&BV_SessionID=@@@@0046599084.1175162949@@@@&BV_EngineID=ccdiaddkhmjdkfmcefeceeldgondhgj.0&cacheID=ieie


Bolt extraction
http://www.radionics.ie/cgi-bin/bv/rswww/searchBrowseAction.do?Nr=avl%3aie&N=4294962142&name=SiteStandard&forwardingPage=line&R=4236685&callingPage=/jsp/browse/browse.jsp&BV_SessionID=@@@@0046599084.1175162949@@@@&BV_EngineID=ccdiaddkhmjdkfmcefeceeldgondhgj.0&cacheID=ieie

http://www.radionics.ie/cgi-bin/bv/rswww/searchBrowseAction.do?Nr=avl%3aie&N=4294962142&name=SiteStandard&forwardingPage=line&R=2642230&callingPage=/jsp/browse/browse.jsp&BV_SessionID=@@@@0046599084.1175162949@@@@&BV_EngineID=ccdiaddkhmjdkfmcefeceeldgondhgj.0&cacheID=ieie

Is there a builders-merchant or that kind of thing I can buy these at in Dublin ?

MercMad

Radionoic are in Dublin, Herberton Road Rialto I think !

Phone them to see if they have stock & you could collect 01-4153100

mike65

Radionics don't allow Opera browsing! :mad:

Mike.

Torq

Hi,
Your links have timed out, if the extractors you are looking at are the spiral type give them a miss!! They are made of very hard but also very brittle steel and if you put the slightest sideways pressure on one it will shear off and then you are in big trouble.
If you can get the remains of the dril bit out the type of extractor to use is one of these,



They are on the following site,

http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=10529&group_ID=1262&store=snapon-store&dir=catalog

Personally I usually drill out the bolt as deep as possible then hammer in an old allen key, apply heat and then turn the bolt out with the key.(most times, but not always!!)

If you can't get the drill bit out then get the welder out and build up the remains of the bolt till you can grip it with vise grips and unscrew. The heat of the welding should free up the bolt.
Keep well,
Torq

franksm

Torq, guess what happened.

Go on, guess. It ain't nice.

Had a nice hole drilled all the way into the offending bolt and this morning was winding in a nice, new Draper stud-remover/eazi-out. All was well, it started to bite into the bolt and.... <crack> the stud-remover broke off inside the bolt.

And since it's really REALLY tough material, I have no hope of drilling it or punching it out... so I'm now in the process of removing the head from the car. Not nice.

Anyone know a good engineering firm that could work on it for me if I bring the cylinder head to them ? Might be easier to put a second-hand head on the car but... lets see how this pans out.

Spit62500

You could try Loftus Farrell in Harolds Cross (454 0609). They should be able to sort it out for you.

Alternatively Howard Engineering in Glasnevin (882 7555).

Rovi

Too late now, unfortunately, but I swear by these-
http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=10418&group_ID=1254&store=snapon-store&dir=catalog

I rarely have to resort to the actual extractors, as the left-handed drill bits usually walk the offending broken part out all by themselves.

Gerry

Following this thread with interest.. Have a bmw e36 up on stands, we are trying to replace the rear trailing arm bushings. Unfortunately snapped two of the bolts holding the trailing arm mounting to the body of the car. They are snapped about 10mm away from the head of the bolt.
They are fairly big, high tensile, possibly stainless steel bolts.
Would that snap-on kit be good enough to extract them? A lot of advice says "drill them out", but its hard to be accurate when working upside down. Tried some teng extractors, but they just turned to butter.

franksm

Latest update: finally got the exhaust downpipe off the manifold, but will be leavin the manifold on the head as it's less bother that way. Got the intake manifold off (book says to leave the manifold on the head, but it's going to be too heavy for me that way).

Was looking for the gasket on the intake manifold and found... there was none. Just some "gasket in a tube" type of compound. Oh... Kayyyyy... so, someone has been here before me. No probs.

Took the camcover off the top of the engine, sprocket off the camshaft, bits and pieces from the chain tensioner taken apart, then started on the head bolts. Removed oil from the 10 of them so I could see what I was doing... and then saw more evidence of someone being there before me... one of the bolts is destroyed.

The bolts are 12-spline Torx-head type things for which I have the proper tool, but the splines are stripped off one bolt !!!

Going to have to find a welder as per one of the original suggestions, so I can get that bolt off :-(

Bradidup

Best trick and it always works is to get a low hydrogen 29.9 welding rod, blue in colour, they are expensive ie over e2 each and build up the broken stud with a stick plant. Then use a vice grips to extract the stud when its built up, has never failed with me. You can get them seperatly in most good hardwares or welding suppliers.

franksm

Thanks Braididup. I'm definitely getting some welding kit this summer, I need to learn this stuff.

As for the head bolt:

Panic over... I set my camera on "macro" and took a close-up shot of the bolt - the bottom 1/2 of the splines were good, it was just the top half that were screwed. So, I went all-for-broke and hammered the splined bit into the bolt - got it seated well. It gave a satisfying <crack> when I turned it with the breaker bar.

So, all the bolts are out and the head should now theoretically be able to be lifted off

It's stuck fast though. :mad: Sun's in my eyes, so I'll leave the mallet in the toolbox till tomorrow. It's the long weekend anyway, so there's no absolute rush - all the engineering places will be shut.

Tell you what - those pins holding the timing-chain's guides in are the devil's own work. They needed to be slide-hammered out, and there's precious little room unless you remove the radiator.

andyj22

franksm wrote:

Thanks Braididup. I'm definitely getting some welding kit this summer, I need to learn this stuff.

As for the head bolt:

Panic over... I set my camera on "macro" and took a close-up shot of the bolt - the bottom 1/2 of the splines were good, it was just the top half that were screwed. So, I went all-for-broke and hammered the splined bit into the bolt - got it seated well. It gave a satisfying <crack> when I turned it with the breaker bar.

So, all the bolts are out and the head should now theoretically be able to be lifted off

It's stuck fast though. :mad: Sun's in my eyes, so I'll leave the mallet in the toolbox till tomorrow. It's the long weekend anyway, so there's no absolute rush - all the engineering places will be shut.

Tell you what - those pins holding the timing-chain's guides in are the devil's own work. They needed to be slide-hammered out, and there's precious little room unless you remove the radiator.

Good luck Frank

If You-ever need a MiG welder let me know you can use mine anytime

franksm

Thanks Ads... Might get you to set up some training classes in welding

Just to show you guys what I found, it's a conflict of sorts:

- on the one hand are some nice cylinder bores still showing the honing that Mercedes Benz worked into the engine back on day one ! Amazing stuff (doesn't show up in the attached photo tho)

- on the other hand, the piston tops and combustion chamber are pretty badly coked up. More than I expected for a supposed 102,000 miler.

In fact some of it disintegrated when I ran a finger over it... I wonder if I ran some Redex would that have cleaned it...

Anyway, what do you guys recommend for decoking the thing ? I'm thinking of going at it with neat Redex left overnight, and then scrubbed in with a toothbrush. Couldn't find any decent articles on decoking on d'web

Spit62500

I've read that a wooden scraper is good - less chance of marking the piston crown. I think that you're supposed to leave the carbon at the edge of the piston as removing it can increase oil consumption. You also need to be really careful that nothing loose gets between the piston and the cylinder. A generous smear of grease will act as a barrier and can be removed easily when you've finished decoking.