Left-hand drill bits and bad bolts

[Mulley]

A few years ago a got a tip from Kyle to use left-hand drill bits to remove bolts and screws with damaged head. If a screwdriver or wrench can't grab it and impact driver won't work, this is your answer. Skip the EZ-out, they just make things worse and can break the bolt. Then you've got a real problem.

Today I had damaged screws in my clutch master cylinder that I planned to replace. I think every manufacturer carves those screws from old government cheese. They are made from the softest material possible. I tried an impact driver and got no where. It was time to step up my game. I remember the left-hand drill bits. I first started with a small one hoping it would grab and remove as I drilled but it just drilled a hole. I tried anther size and same result. Then I figured it was time to just drill the head off the screws. Ding, ding, ding we have a winner. As the bit neared drilling all the way through the head it caught and backed the screw right out. This happened for the second screw as well.

That was not the expect result. I thought I was going to drill the head off, removed the cap and then use vice grip to grab the of exposed screw. If they didn't work I would use a drift and hammer to back the headless screw out. You can do this because it is no longer in a state of tension. If the threads are corroded you will have to use some creeping oil and possibly heat. Luckily mine came out without more intense measures.

When I have a damaged master cylinder screw, I like to swap them out for exposed head allen bolts. These just so happen to be the same type used in Keihin carb bowls, so I usually keep some on hand.

Big thanks to Kyle, he taught me all of this. I hope this little how-to helps someone else that's having a bad day with a bad bolt.

[Mulley]

I also put some anti-sieze lubricant on the new screws. Hopefully this will slow down the corrosion caused by dissimilar metals.

[bblass]

Left hand drill bits are a must for any shop that works on bikes!

I've had success pairing left hand bits with this style extractor for larger bolts I couldn't get tension off of for whatever reason.

https://www.harborfreight.com/screw-extractor-set-12-pc-61981.html

[springer]

 Sometimes the left-handed or left-twist drill bits do not get the broken bolt/screw thingy out but that's okay.  If you take the time and choose a lefty bit the same size or a tad smaller than the drill bit for the size ease-out for the bolt, you will have a hole to insert the ease out if the lefty bit doesn't do the trick.  ;)

Also, if possible, a little bit of heat applied around the circumference of where the bolt goes in can help.

Dealing with broken bolts can be a huge in the kester.  Just take your time and eventually you will succeed.  ;)

[kylepeterson]

glad to see it worked for you!

the go to for bigger fasteners is the plain old chisle, but it's really hard to not screw up a smaller party like master cylinders, head bolts (yup them too ) and pricey parts on high dollar bikes, with a hammer.

I'd be so happy if manufactures would start dipping fasteners in anti seize, but that might add 2 cents, and they won't ever go for that.

[griff]

The left handed drill trick is a very good one. If you need one quickly, mcmaster carr stocks them and can have them to you in alabama next day for regular shipping if you order before 4pm. We get stuff from them all the time for our shop next day. They aren't the cheapest but I've also never had them send me any junk either.

If someone has access to a tig welder there's good ways to get broken bolts off. I've literally removed hundreds of broken bolts with a welder and left handed bits. I pulled some broken studs out of an exhaust manifold just a couple of weeks ago. The thermal cycling really seems to help. While they are good and warm, I soak them down with some decent penetrating oil. The heat seems to really help suck in the oil kinda like soldering pipes. Using a 3/8" cordless impact seems to help as it won't put so much on the broken bolts that you just end up breaking off the nut you've just welded to it. The vibrations probably don't hurt either for the penetrating oil to do it's thing. I've only had a few that I have been unable to get out.

[LawnmowerRG]

Took a KTM shifter bolt out with a lefty last week. When they work they are awesome. My experience is that they don't work about 60% of the time. That 40% though you look like a champ. Of coarse I am usually working with stuff people have already tried to take out.

[norton73]

 I have had some success with left hand bits, but if it's an exhaust stud or something in an expensive casting, I take it to a machine shop. I've seen too many heads ruined by hand held drills slipping or drilled at an angle.
I have used a drill press to remove stuff I can be sure that I can get perfectly straight.

[David DoubleEX]

For stripped Phillips head screws on like master cylinders, instead of using a typical screwdriver, i can usually get it out using a ratchet with the appropriate size phillips head. Its way easier to put good force on them this way. Unless its totally knackered.

Sent from my VS995 using Tapatalk

[springer]

For stripped Phillips head screws on like master cylinders, instead of using a typical screwdriver, i can usually get it out using a ratchet with the appropriate size phillips head. Its way easier to put good force on them this way. Unless its totally knackered.

Sent from my VS995 using Tapatalk

Motorcycles, cars, made by Japanese companies along with a couple of other far east companies do not use a typical screwdriver Phillips head tip.  They use a JIS tip. ( I think JIS it Japanese Industrial Standard) They are a bit different but do look the same.

I solved that problem by buying a set of these;

https://www.google.com/search?q=japanese+screwdriver&source=lnms&tbm=shop&sa=X&ved=0ahUKEwjaoZmw1YbcAhXGrVkKHdMyD9kQ_AUICigB&biw=1366&bih=635

Got turned onto them by the original owner/operator of the old Custom Performance shop when it was located on the Bessemer Super Hiway   many moons ago in the 80'.  ;)

A lot of folks think the factory applies to much torque to them and that is what makes them so hard to get out but in reality it is just the wrong tool.  ;) 

Another good tool for stubborn bolts is a hammer and a impact driver (with the correct bit/socket of course) You just need enough room for the driver and the swing of the hammer.

[LawnmowerRG]

A good impact driver will save your bacon many times on Philips and slot head screws.

Springer you are very correct. You can tell JIS screw by the fact it should have a small dot between 2 of the slots.

[Mulley]

A good impact driver will save your bacon many times on Philips and slot head screws.

Springer you are very correct. You can tell JIS screw by the fact it should have a small dot between 2 of the slots.

Totally agree on a good impact driver. I used to own a cheap one but stepped up to a nicer one and it's a must have tool for every enthusiasts garage. In my case the screws was already toast.

I don't think I've ever seen the dot on JIS screws before. I have to look for them next time.

[kylepeterson]

very good stuff here!

the jis are great for the cheese n peanut butter screws that are used for light duty fasteners like Masters/covers/etc, if they haven't corroded yet. corrosion is 99% of the problem, it sneaks in and swells the bolt in the threaded hole, but with nasty crystals (like sand) instead of the smooth plastic that loctite leaves behind.

I'll second all the heat+ vibration  recommendations here. if you heat one side and spray penetrant on the other, it will wick through like Griffs recommendation of soldering pipes.

if you see a white /green /Rusty Gino around a fastener, hit it with some penetrant and heat before you start, it makes a world of difference!

[LawnmowerRG]

I don't think I've ever seen the dot on JIS screws before. I have to look for them next time.

They are in every Japanese Carb you have worked on.