Broke an Exhaust Stud on The LeMans 5

[MikeW]

 It's been awhile since I've had a stud break on me so I can't complain.

One of the exhaust studs was coming unscrewed or pulling out on the right side so I thought I'd better do something about it. That was my first mistake. So with some lube I managed to get it to free up a bit but it wouldn't unscrew in either direction more than a few turns before binding. Of course it was when I screwed it in that it broke off level with the exhaust flange 

Then I tried drilling it and using a new fangled broken stud remover. Unsurprisingly it didn't work. Rather than risk damaging the head I've booked a "thread doctor" to come out and exorcise the evil broken stud spirit for me

Mike

[Chuck in Indiana]

 In cases like this, you need to drill *right on* center of the bolt, then drill a little (say 1/32") under tap drill size. An eze out will normally get what's left, then you can run a tap in the hole to clean it up.
The trick is drilling on center. Unless you have years of experience doing it, you need to make a drill jig to keep it square and on center.

[Rough Edge racing]

In cases like this, you need to drill *right on* center of the bolt, then drill a little (say 1/32") under tap drill size. An eze out will normally get what's left, then you can run a tap in the hole to clean it up.
The trick is drilling on center. Unless you have years of experience doing it, you need to make a drill jig to keep it square and on center.

  Yes................ .When a bolt or stud unscrews just a turn and jams you cam be sure the threads are screwed up ,especially if the threaded material is aluminum.... Often the stud or bolt has become hardened making it difficult to drill unless you can apply a lot of pressure using a low speed.....Very hard to do with hand held tools using thin drill bits. Using an oxy torch with a small tip I have heated the stud/bolt red hot for as long as possible then let it cool. This can anneal the bolt making it easier to drill. Done carelessly, this can make a mess and require pulling the head for welding repairs.....And sometimes the head needs to be pulled and set up on a drill press.............I t is what it is and you'll have to do what it takes....

[Vagrant]

for what it's worth when I broke my first stud on an EV I replaced it with a Allen head stainless bold. softer and will stretch a bit. it's been in there 40000 miles.

[PeteS]

You can make it easier to start the drill on center if you take a dremel with an abrasive bit and grind a crater in middle. Easier to control an abrasive then to keep a drill bit from bouncing around.

Pete

[Hymes Inc.]

You can make it easier to start the drill on center if you take a dremel with an abrasive bit and grind a crater in middle. Easier to control an abrasive then to keep a drill bit from bouncing around.

Pete

:1:
Have had a few broken studs on my V65c but I do quite a few at work so I have a good feel for it. If the stud isn't bottomed out I've had some luck with a left handed drill bit. When it starts to break through the bottom of the stud it may grab and unscrew. Like to use my 12v impact or set the drill to slip so not to break the bit.

[Tobit]

for what it's worth when I broke my first stud on an EV I replaced it with a Allen head stainless bold. softer and will stretch a bit. it's been in there 40000 miles.

That sounds like a good idea.  Taking it one step further, would there be any advantage to drilling the stud hole out larger then tap and Heli-coil before using an Allen head bolt?

Tobit

[Chuck in Indiana]

That sounds like a good idea.  Taking it one step further, would there be any advantage to drilling the stud hole out larger then tap and Heli-coil before using an Allen head bolt?

Tobit

Personally, I wouldn't unless the threads are compromised.

[MikeW]

The Thread Doctor dropped by today and inside of 15 minutes the broken exhaust stud had been drilled, ground and helicoiled. He did try to remove it first but it was well and truly stuck and not going to budge using an easy out.

All in all happy with the service and would recommend him to anyone in Melbourne Oz.

Mike

[balvenie]

Good luck to you, Mike