Sheared off Drain bolt

[PwrManDan]

Hey all,

While attempting to replace the cooling system fluid, I broke the bolt putting it back in.  I was attempting to torque to 5lbs.

I can not seem to get a drill bit to stay centered on the screw to try to drill it out.  I was going to use an easy out, but after reading on the forum that easy outs could be more harm than good, I thought I would take a deep breath and consult with an expert.  Does anyone have advise?

Thanks all,

Dan

[Rick G]

If you have a Dremel  , us a small stone and grind a dimple in the middle . This will be easier to keep in the centre than a drill bit. Get a left hand twist drill, about 1/4 to 3/8 inch. drill the hole with the drill in reverse, this is  important. when the drill starts cutting it will have the tendency to unscrew the plug. Be cautious and gentle,  the drill can break too, but they are  usually tougher than an easy out.

[kwells]

Center punches are designed specifically for that purpose.

[Rick G]

Sure they are , but they require lots of pounding to make a dent and the radiator wont like that . Besides they can be difficult to get exactly on centre when you hitting it. I learned long ago to make the centering dent , with a Dremel and a small stone.

[Hartless]

It's on he head, Not the radiator... At least from what I can tell in the picture. Not that it makes a difference.... Just sayin :)

[jefferson]

You might try getting a nut that is smaller than the bolt and then weld down through the hole to the bolt. Then you have a nut to get hold of and back the bolt out. It would be better if the bolt was broken off flush, but I think it should work looking at the picture.

Jeff

[Jimustanguitar]

if it's still near the surface and you're not interested in drilling it out, I've used the cutoff wheel on a dremel to cut a slot in bolts before. Then they can be turned out with a flat blade screwdriver. This only works if it's flush or a little proud though, if it's recessed you risk hitting the jug's aluminum with a cutting tool.


Are these drain bolts known to go bad over time? Perhaps it should be on the suggested upgrades list. Maybe I'll go to the hardware store and try a stainless replacement.

[Rikugun]

Are these drain bolts known to go bad over time? Perhaps it should be on the suggested upgrades list. Maybe I'll go to the hardware store and try a stainless replacement.

Maybe due to dissimilar metal corrosion the bolt was weakened and subsequently damage during removal. I guess if you remove them, don't put the original back in!    :)

I'd try the reverse twist bit method. I noticed they have them at Harbor Freight. Getting the center punched hole centered is critical and it takes some experience with broken fastener removal to get proficient at it. Even with a centerpunch, the uneven fracture face often causes the bit to wander some. It can even push the centerpunch off course. I've had to resort to drilling at a slight angle initially then slowly bring the drill up straight as the hole approaches the point where I wished it to be originally.

EDIT: I just looked at the pic again and think I'd try something simple - a very small chisel and hammer. Just use the very edge of the chisel on one of those projections that are proud of the cylinder block surface. Use the chisel and hammer to back the screw out. Be mindfull of the best angle to use the impact energy to it's best advantage. Given the low torque it broke at I think it will easily come out and have done similar removals before using this method. On things that are very stuck it helps to dull the chisel slightly as a properly sharpened one will cut rather than move the broken screw. I doubt that would be an issue here. Small taps in the right direction and angle and you may be rewarded with the sight of it backing out. No drilling, welding, slot cutting, dremel dimple makin' special bit buyin' stuff required.  :laugh:

[Rick G]

Sorry , I got the idea it was the drain plug on the radiator! The cylinder drain plugs do not have a reputation for failure. This is the first instance I've heard of. As for me, I don't remove them . I flush the system with the bottom hose removed and everything will wash out.

[pullshocks]

I have had good results with these...

http://www.praziusa.com/grabit.html

You still need to get a good center point established as Rick G describes.  But you do not have to drill as deep, and they are much stronger than an EZ out of similar size.

[Rick G]

looks good! Might work , let us know!

[Lucky]

Auto Zone sells a small pack of lefty drill bits

[motoracer8]

That's just a 6mm cap screw, 5 ft lbs is too much, it screws into aluminum, snug is good enough.

[PwrManDan]

Update and thanks.

Thank you to everyone who has posted possible solutions to my problem.  My boy and I tried to work out each solution in such order that if one failed the next in line would option would be still available to us.  In the end we drilled through too far and ruined the cylinder.  I think our biggest error was being too eager to finish.  I also had my 17 year old son at the controls of the drill (not to bash him, he has been very helpful), due to a back injury that has plagued me since I was a kid.  So now that the embarrassing part is out of the way; I am back for help and expertise from ROV!

We have a donor engine as we bought a parts bike from a guy in Cleveland (more on that later).  We managed to get the cylinder jug without hurting it.  Now after reading on the site daily, I wonder if it is ok to use the donated jug with the old piston, and not have to worry about the rings being appropriate for the new cylinder.

Also, we pulled the cams off of the head without removing the timing gears, should I re-install them they way they are, or should I pull them apart completely and start over?

I have new gaskets from Tiger and I think we are ready to proceed but want to wait to hear from you all to see if there is more that I need to do before I prep and tear down on the bike that has the damaged cylinder. 

Hope I'm clear, and thanks for everyone's help.  I sometimes get my self in over my head, but I just don't have the funds to go to a mechanic everytime I screw up....I just learn and move on.

[fret not]

Maybe it would be possible to repair the botched drill hole without removing the cylinder.  A pic might help.  There are several types of thread inserts available and even an oversize bolt could work.  Again, a pic might help.

[Rick G]

I would use the new cylinder and the piston that  goes with it. How ever you should check ring gap  and skirt clearance . This can be done with a feeler gauge. Checking skirt clearance takes practice  and a bit of skill. If you can, get them miked by a machinist.
Don't worry about the cam gears , leave them on , no  reason to pull them off. Can you provide pics?

[PwrManDan]

Fret Nut, the newly drilled hole goes all the way throught the cylinder. 

Rick,  I do have feeler gauges, and will take some pictures to help.  It may take me a couple of days.  Please let me know what you want me to take pictures of exactly and I will upload them.  I'm happy about not having to take off the cam gears.

Thanks everyone!!!

[fret not]

 "the newly drilled hole goes all the way throught the cylinder.  "

By this, do you mean the drill went clear through the iron liner into where the piston is????  Or just through the water jacket?

[PwrManDan]

Sadly, all the way through  :-[

[fret not]

 :oOh!  Sorry about that.  That's bad, would "let the smoke out", so to speak.