HarleyTechTalk

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When removing the exhaust on my 93 XLH one of the exhaust studs on the rear head broke.  As you can see it broke pretty much flush with the flange nut, not flush with the head.

What's a good way to try to remove this broken stud without taking the head off the bike?

By the way, what's the procedure for removing un-broken studs?  Double-nut?
And what's the procedure for installing a new stud?

I couldn't find anything in the Service Manual about R&R exhaust studs.  Most posts about broken exhaust studs seem to involve breaking the nut flush with the head but since I have some remaining stud to work with I am hoping I'll be able to remove it in-place...

could you weld a nut to the stud?  let it cool and then use heat around the head and some kroll or other liquid wrench type spray.

There are various makes of stud extractors that fit over the outside of the remaining portion of the stud and you then drive them with either a 3/8" ratchet or a box wrench.

As an alternative to the stud extractor you could try a small pipe wrench - heat the area first with a propane torch.

Thanks.

I had thought of the weld-a-nut-to-stud but I don't have a weld.
I don't think there is room for a pipe wrench.
So, it will be off to the store to get some stud extractor(s).

How about installing a new stud: double-nut, or do I need to use a special tool?  Install it dry?

vice grips

JMHO looking at the threads left on the stud. You might be able to double nut it.  Spray it with some penetrating oil.  Heat it. Give it a few taps with a hammer and try to remove. 

Quality......vice grips.

Jeff

Pretty much, any of the above. I would try the double nut as the first option with spray then heat and a gentle rap with a hammer to loosen any crud or locktite that is holding the stud in place. Tricky stuff as the stud is heat treated especially being the exhaust stud and is brittle. Be careful and once it does break free try removing it a thread or so then go the other way as if tightening and repeat until it is free enough to come all the way out. Once you do have it out use a thread restorer and clean the threads up well then use air to blow all the crud out. Put a dab of antiseize on the threads of the new stud when you install it. Spidey.

Don't want to discourage any of the ideas posted.I will say,generally,a broken exhaust stud is prolly the worst thing you'll ever have to remove. You'll come up with "words,and phrases" that haven't been thought of.
What 99% of the time works for me,is to tig a nut on the existing piece of stud,and use a socket to remove while hot(not cherry red).If it breaks flush,you can try a Jim's drill jig,with a GOOD 1/4" drill bit.
Any event, GOOD LUCK............
John

He asked if double nut to install new one!
Yes,
don't use vice-grips on the new stud. Anti-seize on the threads into the head.

Thanks again.

I didn't have time to try to resolve it today.  But I did hear from the shop that assembled the heads that they use red loctite to install the studs...  I don't think I will buy a weld but propane torch.  There might be enough threads to get one nut and a jam nut on, that will probably be my first attempt.  I'm not sure if there is enough space to lay any muscle on a wrench, it's kind of tight between the head and the oil bag.

Wouldn't red LocTite already be melted just from exhaust temperature heat?

Quote from: jsachs1 on January 11, 2010, 04:47:17 PM
Don't want to discourage any of the ideas posted.I will say,generally,a broken exhaust stud is prolly the worst thing you'll ever have to remove. You'll come up with "words,and phrases" that haven't been thought of.
What 99% of the time works for me,is to tig a nut on the existing piece of stud,and use a socket to remove while hot(not cherry red).If it breaks flush,you can try a Jim's drill jig,with a GOOD 1/4" drill bit.
Any event, GOOD LUCK............
John

Those studs become like a part of the head. A lot of the time drilling them to nothing is the only way to remove them. One thing you have going for you is that the stud in question is accessible without removing the head. Using that drill jig is a good idea as you must drill dead center and straight. The studs are about an inch deep in the head.   

JB

You're lucky you have enough left to bite on too.  The best method would be to mig weld a nut onto the stud.  Dont worry about the threads, use the next size larger nut.  If no wleder is avalable the what you need is HEAT, Lots of HEAT.  Get the stud red hot (or close to it ) and slowing apply pressure with a vice grip or something comparable.  Once you feel the stud break loose, even if its a 64th of an inch..stop.  Now work the stud in and out (with heat applied) til it begins to spin out freely.  If you are patient and take yout time you should get the sucker out in about 20 minutes.

Good luck. 

Also use a butane or propane torch.  DO NOT use map gas unless you're planning on burning holes in the head.  MAP can get hot enough to melt aluminium.

One more thought.  J&P use to sell a jog with the proper drill bit and tap for head stud removal.   Personally, I wouldn't attempt to drill the head withont removing it first.

Also remember,that the stock MoCo studs are a slight interference fit.
If you try heat only,then melt some candle wax on the stud/head,and let the wax wick in.Can work 20% of the time.
John

Quote from: trück on January 11, 2010, 09:07:05 PM
Wouldn't red LocTite already be melted just from exhaust temperature heat?

No.  Locktite is only soft when hot.  I'd never use red locktite on an exhaust stud installed in aluminum.  That's just asking for trouble.  They should be installed with antisieze only.

Lew 

Are those studs threaded or pressed in?

Thanks for all the advice.  I admit I was prepared for defeat... but success!

Went to the dealer and got two new studs.  Parts guy tells me to make sure to get MAP gas when buying the propane torch...

Then, to the hardware store.  The "stud extractors" they had didn't look too promising so I skipped on those, got nuts, PB Blaster and a propane torch:


I had hoped to be able to get two jam nuts on the stud.  Well, there was no room for even an open-ended wrench between the head and the oil tank - until I removed the battery and battery-box and flipped the wrench over, then I could get to it from the left side.


Soaked it with PB Blaster and started with a regular nut.  There is a un-threaded portion on the stud, between the fine-threads and coarse-threads.  I forced it a little bit, not too much but pretty good - I figured if I break the stud loose "inwards" that would be ok too - and over that un-threaded portion.  I got it on so much I could use a regular nut as the second nut too.  Youza - reaching for the propane torch.


But while tightening the nuts together I though I'd try without any heat and with almost no force at all the thing came out.

There was not a trace of any loctite or anti-seize on the stud either - this is the coarse threaded portion.




I've decided to r&r the other stud on that same head too so it's getting a soaking of PB Blaster now.  Hopefully it will come out as easy...

Disappointed I didn't get to use my new propane bottle.

Quote from: surf on January 12, 2010, 02:22:50 PM
Are those studs threaded or pressed in?

Threaded - half of the stud has coarse threads, that end goes into the head.  The other half has fine threads which the exhaust flange nut goes onto.

Quote from: jsachs1 on January 12, 2010, 06:29:52 AM
Also remember,that the stock MoCo studs are a slight interference fit.

Had hoped to find a torque number for installation, but nothing appears to be written about installing these studs in the manual(s) or any instruction sheets.
Will it bottom out, or just a "nice tight" fit?  I guess I can always look at the other studs to see how far they stick out and use that as a reference too.

that PB Blaster is some good "Potty mouth"....

I'm really glad for you.   Was afraid that was going to go south on you and be a real pita (would have for me, LOL).  You must be living right! 
jt

I know they're not the "proper" studs, but I picked up a handful of studs at the manufacturing plant where I used to work.  They're made to be installed with an allen wrench so I just bottom them gently, don't torque them.  When I need to remove the exhaust, the stud comes out easily.

When I install the exhaust, I use anti-seize and torque the nuts.  No more broken studs.

 Way to go Lars !!!!