UH OH broke off an exhaust bolt

[jjthekj]

My buddy and I just recently reaquired an old 350x (Fur's first big boy wheeler). And promptly broke off one of the studs sticking out of the front of the head that holds down the exhaust flange (headpipe). Now what do I do? A few other bolts have stripped out or broken, and that's really nothing unusual for an old neglected machine. I'm pretty well versed in drilling and tapping out bolts then replacing them, but what to do in the case that you break off a stud?

[400exdad]

Do the same thing... just don't drill too deep, you may find yourself in the combustion chamber. :D

[jjthekj]

I'm hoing I've already learned my lesson about drilling too deep! Ha!:devil: But how does one replace the stud? It's not a bolt screwed into the head. It's a threaded rod protruding from within the head itself.
By the way this is the first of 4 nuts to be loosened. I sprayed them all down with liquid wrench prior to attempting to break it loose. I tried to convince Fur (my ridin'/wrenchin' buddy) to continue to saturate the nuts each time he passed the bike in the garage over the course of a couple of days. So naturally he threw a socket on it and snapped it right off! The other 3 are awaiting their demise.

[UglyMotha™]

No the stud indeed is threaded into the head just like a bolt and you can readily buy new ones from your dealer the biggest problem tends to be getting the old one out

[toby400ex]

An easy out didnt work for me. I had to get it completely drilled out then a threaded insert put in. Money well spent :mad: :rolleyes:

[deathman53]

heat the nut up with a torch, shouldn't break then. make it red, then let it cool for a minute(still for the nut to be very hot to the touch) and put the socket on, shouldn't break it.

[UglyMotha™]

there is no nut :huh

it's a stud

[deathman53]

there is a nut at the end of the stud, trust me on that. its probaly so rusted on, that you can't tell.

[UglyMotha™]

:confused:


he snapped the stud off which means that nut is loooong gone

[Ryan]

Easy outs will most likely do the trick.

[big-guy]

PB Blaster. That stuff kicks *****. Then thread a couple nuts onto the stud, and jamm them together. If it's broken flush, weld a nut or something onto the end of it so you can get a grip.

[400exdad]

For the 3 nuts that you haven't broken yet, use a torch like someone else said. Try to use a tight flame to heat up the nut and not the rest of the head and exhaust flange.

For the one you've broken off already... personally, I hate e-z outs. They never work.... 99% of the time anyway... and are the hardest material known to man! :D Do yourself a favor and go get a heli coil kit for the right size stud/nut... you may have to go SAE on this one because a metric one might be hard to find... then drill it out and install the heli-coil. Put in the right size stud - sae or metric and your're ready to roll. Don't think about drilling and tapping the hole to the next size up... it will only cause further problems like drilling out the flange, making sure the flange is turned the right way, socket and wrench clearance between the headpipe and nut.....

[jjthekj]

I'm done with easy outs. Instead of just grabbing the bolt and spinning it , the easy out almost invariably digs down into the bolt expanding it and preventing itself from performing it's task. Then, in one last attempt, you end up breaking off the end of the easy ouy in the broken off bolt, making it so you now have to drill through the easy out!
Thanks for the help everyone. I'm cautiously optimistic that I can work it out. I'll try heating the other 3 nuts and we'll see how it goes. It's good to have friends with a machine shop when chit gets too thick in the garage.

[jjthekj]

Well sure enough, Fur managed to break off 2 more of the exhaust studs. Luckily, the 4th unscrewed itself with the nut. He took it to our friend Tony's machine shop and had him fabricate 4 new studs. We drilled out the old ones, (carefull not to drill too deep) tapped out new thread, and reassembled the header with fresh seals (in stock @ local dealer).


NOTE: To install the stud you must tighten 2 nuts against each other on the end of the stud (to lock them in place on stud), then wrench on the outside nut to screw the stud into your threads.

[jjthekj]

By the way, thanks EXDAD your advise is sound. We used the leftover stock stud material to tap into. Keeping the stock (8mm?) thread size.