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rounded bolts on roter

Old 09-16-13, 09:11 PM
  #1  
CanadianBiker32
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rounded bolts on roter

Ok now I have a new problem. trying to remove a rotor off from disc brake in front. I got almost all the bolts out except for 2. now the bolt heads are starting to round out, the screws seem to be a bit stuck as well, i put in oil , wd 40 between them
now with the screw heads almost rounding out, i know its complication what can i do to remove them
can i drill into the screws?
suggestions please.
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Old 09-16-13, 09:20 PM
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If you have a Dremel tool or similar, use a cut off disc to cut off wither side of the nut to make two flats. Then grab it with a pair of vise-grips and turn it off. If you work carefully, you shouldn't score the disc, but even if you do slightly it doesn't matter.
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Old 09-17-13, 01:38 AM
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I bet the rotor bolts are allen bolts (inbus)?

For stuck allen bolts, a proper sized torx bit hammered into the rounded allen will do the trick and grab it quite nicely. I'm not sure about how strong is the rotor flange from the hub, so don't get carried away hammering.

Other version is with easyouts, no need for drilling, since there is the allen hole, so get a rather big one to fit the allen hole at the very start of the easyout and unscrew it.

Also heating the thing with a heat gun will help (it will expand the bolt lengthwise, and the aluminium flange will expand around the thread releasing it)

Last edited by Asi; 09-17-13 at 01:41 AM.
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Old 09-17-13, 02:26 AM
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I don't like easy outs much. If they snap - and they're just as brittle as thread taps - you've lost every chance of drilling the the screw/bolt out afterwards. Hammering in a Torx bit is a method that comes highly recommended, although I haven't used it myself much. Heat is often good. Something as simple as taking a soldering iron/gun and holding the tip against the screw for a minute or two can do OK on smaller dimensions.
FB's suggestion of filing flats is nice, with the added bonus that if the head(s) should snap right off, the rotor can come off, there'll be no tension on what's left of the screws, and that should make it easier to grab them with a set of pliers and unscrew them.
My personal favourite is to put a small nut on top of the offending screw/bolt, and weld the nut to the bolt through the hole.
A brand new tool interface, and some nice intense localized heat. Hasn't failed me yet.
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Old 09-17-13, 02:53 AM
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Welding is a nice way to remove nasty sheared bolts on aluminum, like a bleed bolt from a brake caliper that snapped (in automotive especially).

But for a bike, welding splatter is nasty.

Torx hammered works best, just find the one that almost fits and hammer it lightly, the edges and points on the torx will bite. I used this method many times on allen bolts that were stuck and rounded like for the centering bolt for brake rotors on cars, and other misc. bolts. Never failed.

A great deal about removing fastners and not rounding them is using the correct tools and nice quality and proper material. A cheap hobby tool is made out of mild steel or anyway an elastic steel that will bend under pressure and that deforms the business end of the wrench, it makes poor contact with the fastner, it will get to a more point or linear contact on the fastener (with great loads applied on one point, one edge, - Hertzian contacts and efforts) that will distort the fastener and round it and make the wrench slip.
A nice professional grade wrench is hardned steel that is also very brittle and added in crome-vanadium, or even tungsten. This will likely shatter than bend, so the shape is solid and the breaking point for the wrench is very high so shattering will most likely not happen, if anything it will shear the fastner before any rounding or shattering the wrench.

This story about hobby vs pro wrenches is very true for automotive and upper bolts (in diameter and in torque applied). For a bike no worry, a decent M4-M5-M6 allen key is pretty much everything you need for bike bolts. - just avoid crappy chinese 1/4 hex bits or L shaped allen keys.. those are junk.
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Old 09-17-13, 04:57 AM
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Every modern rotor bolt I've seen is a torx T25(if memory serves) fastener with thread locking compound pre-applied. If there is still something to get a proper wrench on, some heat will soften the thread locking compound. If the heads are completely rounded, grind or file the heads off and remove the rotor. Then clamp a vise grip onto the remaining portion and remove.
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Old 09-17-13, 05:41 AM
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Are you sure that you are using the proper tool? Many rotor bolts have Torx T25 sockets. Trying to use a Torx driver on a hex bolt (or vice versa) will round out the socket for sure. As to penetrating oil, WD-40 is a poor choice; use Kano Kroil or PB Blaster instead.
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Old 09-17-13, 06:31 AM
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Originally Posted by dsbrantjr View Post
Are you sure that you are using the proper tool? Many rotor bolts have Torx T25 sockets. Trying to use a Torx driver on a hex bolt (or vice versa) will round out the socket for sure. As to penetrating oil, WD-40 is a poor choice; use Kano Kroil or PB Blaster instead.
I would say most rotor bolts are Torx. The OP did not mention type.
If they are hex head, there is an extractor tool made for stripped heads. OP, do you have a Princess Auto store nearby?
http://www.princessauto.com/pal/en/K...-Set/8420556.p
I have this set, but have not encountered a stripped fastener to try it on since acquiring it.

Last edited by Dan Burkhart; 09-17-13 at 06:34 AM.
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Old 09-17-13, 09:33 AM
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One more thing if they happen to be allen screws.

Throw away your allen wrench and get a new one. When those things wear down (and they do) they continue to cause problems until you break down and get a new one. If you have a bench grinder you can make do by grinding down the one that you have but, for no more than allen wrenches cost, what's the point?
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Old 09-17-13, 12:19 PM
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ok all thanks. I got the rotor off. I used an iron on the screws and it work.
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