Broke one head-bolt, when taking the engine apart...

[Hydro-T20]

As said, one of the lower sylinderhead bolts broke when I was taking the engine apart for the rebuild, the bolt was really rotten so I`m guessing that the head gasket was leaking from the cooling channels around the bolt and it corroded it...
The bolt left a stud about 5-6mm outside of the block, so we tryed heating the stud with a torch and used a wisegrip on it-didn`t help.

But when heating it I was very careful not to heat it to much, cause I was a little bit ancious that it was pretty close to the bottom sylinder-sleeve(syl 6), since these are fitted during heated block and all...Is this just me beeing too careful?
When looking at the stud it looks like it should come out of there with enough heat on/in it..

We were also thinking of welding a piece of flatbar to it, drilling a hole in the flatbar and placing it over the stud and weld, this would have given the bolt alot of heat pluss that we would have gotten alot of torque on the stud(this may also result in it breaking even further down, if it really sits in there....And we don`t want that to happen..

So as usual I find myself asking for your advice...

[Jay Smith]

If I had a block with a broke stud that had that much sticking out of the thread I might do it 3 ways:

1. Heat the bolt boss arount the bolt NOT the bolt and try after heat is applied spray some "liquid wrench" on the bolt and repeat several times then try the vice grips.

2. Next if you have a Tig welding machine radius the stob sticking out and do the same with a bolt of the same or near the same size and weld the bolts together as soon as the welds cools for a matter of seconds put a wrench on the welded bolt head and gentle unscrew... ( The heat of the welding will transfer through the bolt loosing it as well as giving you a a more substantial place to anchor a turning device to the bolts ! )

3. Put in on a Bridgeport ( or any mill ) lock it down and make sure the deck is flat then with an end mill flatten the stub use a centering drill to start a starting place in the middle of the stub then slowly drill through the bolt gradually getting larger and larger with the drill bit when you get close to the size of the original bolt should be able to use a dental pick or a easy out to remove the remainder of the broke bolt.


Good luck

[Mark75H]

I've had success with all three of Jay's techniques ... drilling with a reverse drill bit sometimes brings the broken bolt or stud out 3 sizes sooner than regular bits ... it's the only thing cooler than going all the way down to just a spiral that looks like a spring (when you are lucky enough to hit dead center with your original hole) :)

[berg969]

we weld a nut on which is easier than trying to weld on a bolt

[shooter1]

Weld a flat washer on first, then a nut on it. Works best with MIG, but don't cool the welded nut. After it cools some you can take an impact wrench and turn it down the pressure and let the hammers in it do the work. Water works as a good lubricant for this also. This is an old welder trick taught to me nearly 30 yrs. ago by the guy that I bought my welding shop from and he had 30 plus years of experience.

Shooter1

[Hydro-T20]

Think I will go for welding a nut on there, my buddy has got both an MIG and a Good TIG-welder att his job, so I belive it can be solved with this...
In an worst case scenario, I can put it on the Bridgeport-mill I`ve got and drill it out, but hopefuly it won`t get to that...
Once again thanks for the reply`s!:)

[Ronnie C.]

Take the bolt that broke off and in a drill press drill a hole in the CENTER all the way thru the bolt.Bolt your head back on with a few bolts.Take the drilled bolt and put it in the bad hole,hold the head with vice grips and drill away.It acts like a guide to keep you going straight in.You just keep drilling both pieces bigger and bigger till you can pick out the treads.It's what us po folks do lol.

[150aintenuff]

if welding wont remove it grind it flat so you can center punch and drill like mensioned... did 8 hub bolts on my 10.5" ford rear end freehand hat way... slow and steady with a lefty drill bit and she shold come back out..

[Hydro-T20]

Thanks to all the good tips from you guys:cool: ..

I must admit I`ve seen worse cases of broken bolts, and somehow they all usually come out sooner or later...Resently I had to drill one out from the sylinder of my 2004 Honda CR 250R...Had to use a Dremel to get to it...broke way down in there, took about 2hours to get it out...with the treads intact.
So I belive the Merc can be saved as well, just thought I would hear if any of you had any great ideas, and great ideas I got:) !

Once again:Thanks for all the answers, I really appreciate it!

[espen]

Many good tips here and I can add one:

You can drill a hole tru the bolt ,use a hand drill and be carefull in the start to change direction on the drill to get the hole in the middle. Drill fairly big hole and find a 12 hex bit that you have to hammer in maybe 6-7 mm, then it can be screwed out if not to tight. In your case I would start with heat and hammer the remains a few good strokes then a wisegrip or "plummers wrench" that gets tighter with more torque.if it breakes of its still possible to weld on a bigger nut. If it breakes you are into the drill untill there are no bolt left

[jerry]

jerry will agree with some of yous. welding a nut on is the best idea and like jay said and the heat will help . once the nut is welded on smack it a few time with a hammer .... dont kill it with the hammer . this will shock the threads .

[Hydro-T20]

As said...:D