Need help removing broken valve cover bolt

[AnotherCO4Runner]

I have been using info from the forum for a couple of years now, to fix some stuff on the 1st Gen I once owned and the 3rd Gen I currently own. I only recently created a profile because I am knee deep in changing my timing belt and doing my valve cover gaskets (and all the other things that one seems to change "while in there".

My problem is one of the valve cover bolts was broken off by the PO, and it was not sticking out of the bottom. I have failed to remove it with left handed drill bits. Things started out pretty good with the 5/64 bit, but after I was making progress the metal seemed to harden and the bit(s) would not work. I have since broken three 5/64, 2 of them were cobalt. I then tried the 7/64 and the hole just got wider but not deeper.

This bolt has derailed an otherwise fairly pain free adventure. I need help getting this broken bolt out.

 

[4Reak Show]

Get the smallest, sharpest chisel you can find. Stake the bolt with a line so that you can then use that line and hit the chisel at a 90 degree angle to get it to rotate. For example: looks like a rear bolt passenger bolt so I would try and make a little line or half line running from passenger to driver side and then use that line you chiseled (mind you a very shallow line) running the chisel from front to rear. Tap on the chisel with a hammer to try and get the bolt to spin. Once it breaks free is should spin by hand.

You can also try using an "impact driver" with a screw driver flat head attachment if you can chisel or dent a small line in the body of the bolt. Look up that tool. It's a spring loaded handle deal that when smacked with a hammer exerts direct rotational force downward. If you can get either of those to bite and rotate even a little the bolt should start to back out.

 

[Morphyne]

I would continue to try and drill it out. But get carbide tipped bits and keep them cool some cutting oil. Oddly enough wd 40 seemed to work for me.

 

[BamaDrewski]

I have been using info from the forum for a couple of years now, to fix some stuff on the 1st Gen I once owned and the 3rd Gen I currently own. I only recently created a profile because I am knee deep in changing my timing belt and doing my valve cover gaskets (and all the other things that one seems to change "while in there".

My problem is one of the valve cover bolts was broken off by the PO, and it was not sticking out of the bottom. I have failed to remove it with left handed drill bits. Things started out pretty good with the 5/64 bit, but after I was making progress the metal seemed to harden and the bit(s) would not work. I have since broken three 5/64, 2 of them were cobalt. I then tried the 7/64 and the hole just got wider but not deeper.

This bolt has derailed an otherwise fairly pain free adventure. I need help getting this broken bolt out.

I assume you have soaked it down with penetrating spray. If I were you, I would take a mini torch and heat the bolt up. I have had similar issues (rusted fog light screws) and I took a Dremel tool with a carbide metal cutting blade and cut a slot in the top of the screw and used a flat-head screw driver to get it out. Might be worth a shot. Good luck!

 

[aykalper]

Try drilling it, but, please put some tape or some cover over the valve train. Don't want metal bits getting into the head!

 

[nobb]

All these ideas are good. You can also try those bolt extractor kits. Also try drilling down deeper with the smallest bit as that relieves the locking force in the bolt. Last resort would be to do a complete re-drill + tap with a slightly larger bolt.

Luckily, this is an area that isn't rusted and the bolt is not highly torqued (atleast it shouldn't have been) so extraction should be relatively easy. Good luck!

 

[yella]

+2 on using the absolute smallest bit. Do you know the bolt length? If you do, put tape with a little "flag" on your drill bit so you dont go to far in.
Use oil/lube while drilling, drill slow, gradually go larger with your drill bits. At the end, i would clean the threads with a tap set.


Sent from my iPhone using Tapatalk

 

[19963.4lsr5]

He is using left handed drill bits. And I think he has a broken off tip of a drill bit in there. He told me it stopped drilling like the metal got hard. I am pretty sure he has a tip broken off down there. The left hand bits didn't grab and spin the bolt shaft out.


Sent from my iPhone using Tapatalk

 

[octanejunkie]

Use the next size left hand bit, maybe it will catch; if not use an ez-out. Be careful hammering the ez-out into a bolt in aluminum.

Good luck

Sent from my Nexus 5X using Tapatalk

 

[davidch]

My first thought any time a broken stud or bolt has an embedded drill bit or screw extractor is to take the piece to a machine shop or welding shop that has an EDM machine. Sadly, that strategy is not applicable in your situation.

Sorry to write this, but I think you'll face defeat with any strategies of cobalt or left hand drill bits. The chisel method mention above might work; access is the biggest problem there.

My strategy would be to employ a small hole saw to drill around the broken bolt. I poked around on the Internet and found this hole saw.

The OD of that tool is, obviously, 3/8", or 0.375. If the tool's ID is over 6mm, 0.236, it should be able to cut around your broken bolt.

(I think Home depot sells these saws. Milwaukee also makes a 5/16" version of this saw, but I suspect its ID is under 6mm.)

That tool is intended for cutting holes in tile. It should have no problem cutting aluminum, though you'd have to clean it often and use a fluid like kerosene to reduce the aluminum clogging the tool's diamond dust cutting face.

I would use a socket and a speed wrench to drive this saw, not a drill. You'll need the steady hand of an eye surgeon and the patience of Job.

The smallest, proper metal hole saw I could find was 9/16". I don't think there's enough aluminum around your bolt to survive a hole that big.

If this operation is successful, you'll have a 3/8" hole you could then tap and fill with, say, a 10mm stud that has its own 6mm threaded hole. Kind of like a Time-Sert with a thicker wall.

It'd be handy to have a friend with a lathe to make this piece for you. I'd get a 10mm bolt and use that as the basis for this piece. A really clever guy with a drill press might be able to make it without a lathe.

My suggested strategy is a lot of work, to be sure. Possibly overkill. But, as they say, it's so crazy it just might work.

 

[AnotherCO4Runner]

Thanks for guidance

After getting some guidance from [MENTION=99144]19963.4lsr5[/MENTION] I had soaked and reapplied PB Blaster to the bolt for 2 days before I even tried to extract. I have been using a propane torch to heat it up before each drilling session and have been keeping the bolt soaked in Tap Magic each time I drill.

I started out drilling with this kit - Search results for Titan? 10-Pc Screw Extractor Set - TP Tools & Equipment and the bit broke. As [MENTION=99144]19963.4lsr5[/MENTION] has said, maybe a piece of bit is still in there.

I then switched up to this set of cobalt bits - https://www.amazon.com/IRWIN-HANSON-Spiral-Extractor-11119/dp/B0002NYBH8 but when the smallest bit broke I went to the next size up, but the whole just keeps getting wide.

I like the chisel/dremel idaes put forth by [MENTION=127339]4Reak Show[/MENTION] and [MENTION=25434]BamaDrewski[/MENTION], since if I do have a bit stuck in there I am note sure drilling more with left handed bits will help.

If I were to try another version of extractor, what do you guys think of this one? - Micro Grabit 4-Pc. Set | Rockler Woodworking and Hardware

I had soaked and reapplied PB Blaster to the bolt for 2 days before I even tried to extract. I have been using a propane torch to heat it up before each drilling session and have been keeping the bolt soaked in Tap Magic each time I drill.

 

[ShannanC]

I would continue to try and drill it out. But get carbide tipped bits and keep them cool some cutting oil. Oddly enough wd 40 seemed to work for me.

WD-40 is a good cutting oil. I use it all the time at work if I can't find any Tap Magic.

 

[theesotericone]

Get a couple 1/16th bits and drill directly against the threads at 0, 90, 180 and 270 degrees. Soak the bolt allowing the oil to get into those holes then use a chisel to turn it. With a broken bit in the mix your gonna find it nearly impossible to drill center. Once removed I'd chase the hole with the correct size tap to clean up any thread damage.

 

[ShannanC]

Get a torch with a small tip and heat the bolt up cherry red (just the bolt and not the head) and let it cool down. Do not spray anything on it until it cools or you will harden the metal and have a hell of a time drilling it out. What this does is expand the bolt that is in the block against the threads and once it relaxes the crap that is stuck in there will be loosened and it should come out easier.

Now looking at the pic and reading your posts I think that you have some broken drill bit in there. Your options are limited.

You need to either drill out the center of the bolt with a carbide tipped drill bit or a full carbide bit and this will relieve the tension from the bolt to the threads as someone mentioned earlier. Carbide will cut through the drill bit pieces.

Use caution and do NOT put hardly any pressure on the drill as the bit will snap as it is very hard, but brittle.

Once you have done both of these steps you MAY be able to back it out with a left hand drill bit or a small chisel with a small hammer to "unscrew" it.

And of course tap the threads once you have extracted the bolt.

I rebuild steam turbines for a living and this is how I deal with this issue almost daily. Good luck, buddy!

 

[19963.4lsr5]

Find a tight fitting torques bit and hammer it into the hole you drilled and use a impact driver on it.


Sent from my iPhone using Tapatalk

 

[LittleCaesar]

If you go the impact driver route, buy some of this and put it on the tip of the bit you are using before hitting it into the hole; my brother's boat mechanics do such when they sometimes run into seized screws thanks to salt water:
https://www.amazon.com/Permatex-80037-Valve-Grinding-Compound/dp/B000HBM80M

 

[2ndhandyotaman]

If you did break the drill bit tip in the hole that it was making in the broken bolt, you can shatter the drill bit with a small, sharp center punch then continue on with the drilling. Wear safety glasses, the shrapnel will go flying.

 

[97FR_brad]

Yikes. Best of luck to you fixing that!! Definitely interested in hearing how you extracted that bolt.

 

[AnotherCO4Runner]

All I have managed to do is make a wider hole

I wasn't able to make a cut with a titanium carbide Dremel bit, so using a screwdriver or chisel was not an option. I tried to to use this kit Micro Grabit 4-Pc. Set | Rockler Woodworking and Hardware. All that I did was make a wider "hole". At this point I am certain I am just cutting into the aluminum, at least on one side of the bolt.

I used a digital caliper and measured the broken bolt against one of the intact bolts and determined there is only 4mm of metal in there. I am pretty sure I have removed 1, maybe 2mm of metal with all my monkeying around. I should have taken a picture before I quit (it is taking up space in my friends garage, since my garage is only big enough for minis or MGs).

At this point I am looking for advice on locating a mobile machinist to come and drill it out and put a heli-coil or whatever. I am over my head.

 

[Famous]

Easy out. You can get them at any hardware store. Fastest and easest way.