Stripped Bolt Head

noob
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noob
Edited Date/Time 1/27/2012 1:47pm
I have a stripped 8mm bolt head on my subframe. What's the best way to get it out?

Drill a pilot hole, then use a bolt extractor? I'm worried about ruining the threads on the subframe.

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***Feel free to nag me about my dirty airbox – it's the only way I'll learn***
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babba boey
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babba boey 11/23/2009 12:03pm
11/23/2009 12:03pm
Try hammering a socket on it and use an impact gun to loosen. Spraw some PB blaster from the other side and let soak for a while.
project racer 11/23/2009 12:47pm
11/23/2009 12:47pm
Take a good ,sharp ( small) chisel and a hammer,catch an edge of the bolt, and give it a few good raps. Put some anti-seize on the threads of the new bolt before you install it.

The Shop

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noob
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noob 11/23/2009 1:35pm
11/23/2009 1:35pm
Wouldn't hammering it damage the threads in the subframe?
90rm125
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90rm125 11/23/2009 1:40pm
11/23/2009 1:40pm Edited Date/Time 11/23/2009 1:41pm
Even if you do mess up the threads its no big deal cause it can easily be tapped out just be careful not to completely screw them up.
project racer 11/23/2009 1:57pm
11/23/2009 1:57pm Edited Date/Time 11/23/2009 2:18pm
noob wrote:
Wouldn't hammering it damage the threads in the subframe?
I doubt it. I have done this on phillips head screws in center cases when the heads have been buggered out with no problems. Take the chisel, place it on the edge of the bolt far enough back to get a groove started without cutting the edge of it off. Give it a couple of sharp raps in the proper direction to loosen the bolt. A typical ball peen hammer should suffice.

If the bolt is seized in the threads, this may not work. As mentioned above, PB blast it, let it soak. In the end , you may end up with the drill, tap and heli-coil as your only solution. A good hardware/tool store should have them, and they are very easy to use.

You will need to know what size bolt and thread pitch you have in order to get the same size as the original. What ever you do, try not to break an extractor or E-Z out off in the bolt. They are hardened and will make drilling from that point on a real SOB. Use a center punch to make a guide for your starting point and try to drill as straight as possible.
FlickitFlat
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FlickitFlat 11/23/2009 2:07pm
11/23/2009 2:07pm
Project racer is right but if you have the drill bit why not use it. It isn't like it is hard to drill. Take an 1/8" drill bit and put through the center to the other side. No need for an easy out because once you have a hole through it the preasure will be off the threads and it will come right out. Maybe use some vice grips.
Who cares if you mess up one side of the threads or not. your not going to wallow it around all the threads are ya? You won't mess them up enough to where they won't work. Even if you did. Run a tap through. Whole thing might take you 5 minutes.
newmann
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newmann 11/23/2009 3:06pm
11/23/2009 3:06pm
Do you understand the chisel approach Project Racer suggests? Might be the easiest, has saved me a bunch of times. The external bolt extractors motofab suggest work well in a lot of situations as well. Another suggestion for drilling it out is to get a left handed drill bit and use it with a reversible drill. Many times it will get the bolt loose before you actually drill through it.
noob
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noob 11/23/2009 3:07pm
11/23/2009 3:07pm
I didn't know about PB Blaster. I'll give that a try.

I'll use the extractor bit if I have to... already broke one drill bit trying to drill the pilot hole. Maybe I was trying to use too small of a bit... I dunno.

Thanks for the help.
CamP
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CamP 11/23/2009 6:51pm
11/23/2009 6:51pm
Can you get a set of vise grips in there?
noob
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noob 11/23/2009 7:13pm
11/23/2009 7:13pm
CamP wrote:
Can you get a set of vise grips in there?
Yes, but can't get enough traction to turn it. It's an 8mm head... completely rounded.

I just bought some PB Blaster and a new drill bit (broke one trying to drill the pilot hole). I'm gonna let the PB Blaster sit overnight.
Cygnus
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Cygnus 11/24/2009 4:14am
11/24/2009 4:14am
It will come right out with the air chisel. I had to take apart an old Yamaha 650 once. The air chisel saved my day.
motofab36
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motofab36 11/24/2009 6:04am
11/24/2009 6:04am
I dont see how the air chisel will work on such a small head.

If you have a small wire welder you can sometimes take a nut that will fit over the rounded head and weld it to the bolt in the center of the nut then use a wrench.
526
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526 11/24/2009 6:07am
11/24/2009 6:07am
Grind the head off the rest will spin out with your finger.
noob
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noob 11/24/2009 11:42am
11/24/2009 11:42am
I sprayed it with PB Blaster and had a go with the chisel and hammer. Didn't budge.

After I get home from work today, I'll try drilling again.

(I don't have an air chisel and don't understand how it would work if I did)
newmann
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newmann 11/24/2009 1:43pm
11/24/2009 1:43pm
Could you just use a dremel with a cut off wheel , grind a slot in it, and use a flat screwdriver to take it out?

Can't believe the chisel and hammer didn't work. Was the chisel nice and sharp? Did it get a good bite into the edge of the bolt head when you hit it in the correct direction to loosen it?

Pit Row

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project racer 11/24/2009 2:08pm
11/24/2009 2:08pm Edited Date/Time 11/24/2009 2:09pm
Has this bolt ever been removed since you have owned the bike? If it is cross threaded, the hammer and chisel trick will probably be ineffective. As 526 stated, you need to grind off the head of the bolt . Don't try and drill through the bolt head.
noob
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noob 11/24/2009 2:12pm
11/24/2009 2:12pm
The chisel edge is dull (and probably too big for this), but I made a little groove with a hacksaw so it got plenty of bite. Yes, in the correct direction.

I'll try again tonight.
noob
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noob 11/24/2009 2:16pm
11/24/2009 2:16pm
project racer wrote:
Has this bolt ever been removed since you have owned the bike? If it is cross threaded, the hammer and chisel trick will probably be ineffective...
Has this bolt ever been removed since you have owned the bike? If it is cross threaded, the hammer and chisel trick will probably be ineffective. As 526 stated, you need to grind off the head of the bolt . Don't try and drill through the bolt head.
No, I bought the bike used and just discovered the head was stripped.

I thought 526 was fucking with me about grinding off the head...
xnationalwrench 11/24/2009 2:51pm
11/24/2009 2:51pm
newmann wrote:
Could you just use a dremel with a cut off wheel , grind a slot in it, and use a flat screwdriver to take it out...
Could you just use a dremel with a cut off wheel , grind a slot in it, and use a flat screwdriver to take it out?

Can't believe the chisel and hammer didn't work. Was the chisel nice and sharp? Did it get a good bite into the edge of the bolt head when you hit it in the correct direction to loosen it?
You can modify that by tacking a flat washer to the bolt and put your vise grip on the washer.
Cygnus
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Cygnus 11/24/2009 6:04pm
11/24/2009 6:04pm
Sorry. The air chisel with a sharp tip will free the bolt up by impacting it while you turn the chisel counter clock wise. Air chisels are like 10 bucks at Harbor frieght.
noob
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noob 11/25/2009 11:09am
11/25/2009 11:09am
project racer wrote:
Noob, check your P/M's. Just some more suggestions.
Thanks, dude!

I'll try some of those tonight. Yesterday was hell... didn't step foot in the garage.

I'm gonna try with a chisel one more time. I bought a 1/4 inch chisel on my way to work this morning. The one I used last time was pretty bulky... probably wasn't getting a good angle on it.
noob
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noob 11/26/2009 11:12am
11/26/2009 11:12am
Got it out with a hammer and smaller chisel.

Thanks for the help, guys!
Big Lenny
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Big Lenny 11/26/2009 7:46pm
11/26/2009 7:46pm
The guy's are experts on "Nut's" too...Whistling
Toneconsultant 12/19/2009 6:29am
12/19/2009 6:29am
noob wrote:
Wouldn't hammering it damage the threads in the subframe?
project racer wrote:
I doubt it. I have done this on phillips head screws in center cases when the heads have been buggered out with no problems. Take the...
I doubt it. I have done this on phillips head screws in center cases when the heads have been buggered out with no problems. Take the chisel, place it on the edge of the bolt far enough back to get a groove started without cutting the edge of it off. Give it a couple of sharp raps in the proper direction to loosen the bolt. A typical ball peen hammer should suffice.

If the bolt is seized in the threads, this may not work. As mentioned above, PB blast it, let it soak. In the end , you may end up with the drill, tap and heli-coil as your only solution. A good hardware/tool store should have them, and they are very easy to use.

You will need to know what size bolt and thread pitch you have in order to get the same size as the original. What ever you do, try not to break an extractor or E-Z out off in the bolt. They are hardened and will make drilling from that point on a real SOB. Use a center punch to make a guide for your starting point and try to drill as straight as possible.
How would you remove a smoothed out Phillips screw head?

I spun out the top of a Phillip screw and I'm just not sure what my options are on how to remove it. It's one of to bolts that connect my oil pump to the engine. Any suggustions?
newmann
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newmann 12/19/2009 8:35am
12/19/2009 8:35am
Use the flat chisel, a small one and make sure it's sharp. Place it on the outer edge of the screw head so that when you strike it with a hammer it will dig in to the metal and turn the screw to the left to loosen.

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