Help! Broken studs in old motorcycle engine..

[xJoey Dubsx]

So I have a 77 Yamaha RD400 and I'm doing a full rebuild on it..
(As seen here: http://garagejournal.com/forum/showthread.php?t=105413 )


Well I bought a new exhaust, so one thing I needed to do is get the exhaust off. Well I took the four bolts off.

Let me rephrase that, I broke the nuts off, bringing some of the studs out with them.

Well I was able to get the exhaust off, took the engine out of the bike frame and tried getting the studs out, which thank got they are studs..

Well next was next, use heat and tons of PB to get the studs out. Well the heat helped to break the studs off right below the flush line. 1 of the 4 bolts came out with heat, but the other three bolts broke.

Needless to say, after drilling two of them hollow, and applying tons of MAP Gas, and using a extractor set, nothing has happened further..

Anyone have any advice? I'm at a loss, and can't get them out for the life of me. I was going to resort to drilling them out completely and retapping one size bigger, but I would really like to use the OE studs..

Please give me some advice, someone please!

Or if you live in the Cleveland area, I can bring it to you if you can get them out!

 

[jhelrey]

Drill them as big as you can without hitting the threads. It will let pressure off of the stud. Then use an easy out from Mac. Works great!

 

[xJoey Dubsx]

Easy outs aren't working though. :/

 

[mitusa]

Are you using the four sided easy outs or the screw shaped ones. The four sided ones are the best....

Have you got left handed drill bits?

 

[xJoey Dubsx]

Yes, we attempted to use both and the screw style.

No, we do not, but thinking about borrowing a guys from work, or bringing the engine into work.

 

[mitusa]

I only use the four sided ones. The trick is to take a small file and file places in the stud for the easy out to fit in. Don't drive the easy out into the hole...it only makes the threads bind more. It's tedious but it works.

In the future, if the studs don't feel like they're going to move, heat the stud again. Hold your torch far enough away from the stud that it doesn't start "melting", and hold it there for a good amount of time. You want the stud to get red hot and hold it there, letting the heat travel down the stud to the bottom of the stud. Then let it cool. Then repeat. Do it till you begin to feel the stud start to move. It's a lot easier to heat a few times and turn it out. Drilling them out is a pita.

I've heated a lot of bolts in heads on tractors. I would heat the stud as above, but as quick as I got it hot and held it there for a while, I would pour a small stream of water on the stud. Two or three times and the stud would usually come on out. I've never twisted one off.

Good luck!

 

[tcsalvage]

are the studs drilled through the center or really close? if they are you can walk up the drill sizes until you see the threads and pick the threads out. if they are off center you can drill until you see threads on one side and take a small round chisel and crush them and work them out. if you have carbide burrs you could groove down until you see threads with three grooves and colapse them in on themselves.

 

[c201971]

put a nut on the stud the size bigger weld the stud to the nut so it heats up the stud and work it back and forth and it may come out. that is how i usually do exhaust manifold bolts when we take them off and break the bolt off. some times after i weld it I have to tap it from the top down it seems like it kind of breaks the rust up when there really stuck maybe this will help

 

[Honda guy]

If the hole is centered, I'd just drill it out to the appropriate size, and install a Helicoil or Time-sert. Then you can use the original size stud.

I'm guessing that a Helicoil kit is going to cost in the $40 range and the Time-sert kit around $80?? You're money might be better spent, just paying an experienced mechanic to take care of it.

 

[srmofo]

Something like that, you might be better to let a machine shop handle it. Our machine shop charges $25 a stud. Other than that, get out the drill and go to town, but if you really want to use the OEM studs you might want to seriously consider a competent machine shop

 

[joeswamp]

There's also a trick where you build a dam with clay around the stud hole and then dissolve the stud with concentrated nitric acid. Somehow the acid will dissolve the stud but not harm the aluminum. This is one method where you really want to know what you're doing.

Personally I'd take it to a machine shop.

 

[Modern Jess]

put a nut on the stud the size bigger weld the stud to the nut so it heats up the stud and work it back and forth and it may come out. that is how i usually do exhaust manifold bolts when we take them off and break the bolt off. some times after i weld it I have to tap it from the top down it seems like it kind of breaks the rust up when there really stuck maybe this will help

I've done it this way several times, with a MIG welder. When you're really lucky, there's enough meat on the stud to weld a nut onto. Sometimes, though, with the studs broken off below the surface, you've got to use the MIG welder to build up some weld on the end of the stud until it protrudes above the surface. This might take several passes to get it just molten enough to add some material and not molten enough so that it drips out of the hole.

Once you've built up a nub, you can weld a nut onto the end of that and turn it.

And yeah, applying high heat to the stud via the welder will often help break it loose and make it easier to get out than it was before. I have been successful every time I've tried this technique, though sometimes it took several hours of work.

NOTE: this only works when the surrounding material is aluminum! Welding the end of a stud in an iron casting will likely not end well.

 

[xJoey Dubsx]

It's a cast engine, so yeah.

I appreciate all the tips!

 

[KMinAF]

Something like that, you might be better to let a machine shop handle it. Our machine shop charges $25 a stud. Other than that, get out the drill and go to town, but if you really want to use the OEM studs you might want to seriously consider a competent machine shop

Isn't there a technique that uses some type of high frequency/sonic machine that "disolves" the bonding corrosion?

 

[osborn.ozzy]

I bet some Kroil would get those studs out.. http://www.kanolabs.com/penLub.html#anchor173855

 

[TommyD]

Take it to a competent machine shop, sometimes it's better to pay someone else for the headache.

If it's below the flush line you could use a drill the same diameter of the hole to center a hole in the stud, then drill tap drill size (or ez out size) and pick out the remaining threads.

As mentioned a heli coil would also work just make sure your hole is within the limits of the hole in the flange.

I think the above poster is thinking about a sonic screwdriver....

 

[c201971]

It's a cast engine, so yeah.

I appreciate all the tips!

we just pulled some studs out of some old 4 speed gm cast trannys pretty much the same way i said earlier but when there broke either flush or down in the whole take a flat washer a little smaller then the hole and cover the hole with that a take ur wirefeed and weld to the stud and the washer pretty much fill the whle up. (wire wont really stick to cast that well) Then take another washer and weld it upright to the other washer and put a vise grip on it and turn they will usaully come out that way to. give it a try it may work for you

 

[KenS]

Broken stud removal with mig welded washer and nut...

Broken stud removal with mig welded nut...

Broken stud removal with stick welder...

Somebody buy this guy an extension...

 

[hunter1151]

If you have a tig welder, I tig weld on top of the stud and build up some metal on what is left of the stud, I then put a nut over the top of what I have built up. I then weld the build up to the nut making it glow pretty red which tends to heat the entire stud enough to expand it and loosen it a bit. I then put a wrench on the nut and work it back and forth a little. I then apply some penetrating oil of some kind to prevent galding on the way out. It has worked almost 100% of the time.

 

[xJoey Dubsx]

Brought it work (4 wheel parts ( and me and a tech got one drilled out, and tapped. 2 more to go

 

[riceburner]

find somebody in your area that does EDM bolt extraction.

 

[duude]

find somebody in your area that does EDM bolt extraction.

x2
I didn't see any comments on driving straight down on the stud. I always drive down on a stud mounted into aluminum with a hammer or air chisel while pressure with wrench, heat, last step edm. looks like you are to the edm stage.

 

[bobadame]

Step 1: Read the book Shop Class as Soul Craft.
Step 2: Easyouts almost never work. They are a wedge and that's what they do to the bolt you are trying to extract. The safest way to do this is to mount the piece in a mill so that the exhaust flange is parallel to the mill table. Center the stud under the spindle and with a pilot drill of the proper size or just slightly smaller, drill to the bottom of the stud. There are left hand drills for this purpose and sometimes they will break the bolt loose as they drill. Re tap the hole and move on to the next. If you are real lucky, the tap will find the original thread. If it doesn't you are in location for a helicoil. If you have to hire this out it should take less than an hour.

 

[Modern Jess]

(wire wont really stick to cast that well)

Good to know! Thanks.