Replacing round brake posts
- Thread starter Mrcheap
- Start date
stanmiller
Active Member
For the Shimano BR-T4000 brake calipers, one would use a 5mm allen wrench on the post.
If the inside is rounded and won't accept an allen wrench, you could try a a vise grip on the outside.
If the inside is rounded and won't accept an allen wrench, you could try a a vise grip on the outside.
stanmiller
Active Member
Next is a left handed drill bit. It will probably wreck the post but will get it out. Left handed drill bits unscrew when the drill is rotating forward.
www.harborfreight.com
.
Left Hand Drill Bit Set, 13 Piece
Amazing deals on this 13Pc Left-Hand Drill Bit Set at Harbor Freight. Quality tools & low prices.
www.harborfreight.com
.
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stanmiller
Active Member
Yes turn the drill clockwise and the bit extracts counterclockwise. Magic!
Then again.... the drill should be set to reverse when using a left handed bit. See post from @McCorby below. I have a set of these bits and have used them on car projects.
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Sierratim
Well-Known Member
- Region
- USA
- City
- Nevada City, CA & Paradise Valley, AZ
YES, another tool for the shop!Next is a left handed drill bit. It will probably wreck the post but will get it out. Left handed drill bits unscrew when the drill is rotating forward.
Left Hand Drill Bit Set, 13 Piece
Amazing deals on this 13Pc Left-Hand Drill Bit Set at Harbor Freight. Quality tools & low prices.
.
McCorby
Well-Known Member
- Region
- USA
You need to spin the drill in reverse/counter clockwise for left hand drill bits... The idea is that the drill bit grabs the broken screw or bolt and spins it out.
rich c
Well-Known Member
If a vise grip won't remove it, a left hand drill bit won't come close. First I'd get a bigger vise grip. If that doesn't work, then I'd shield the rest of the parts and use a MAPP gas torch to heat the post and then a pipe wrench.
stanmiller
Active Member
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indianajo
Well-Known Member
Left Hand Drill Bit Set, 13 Piece
Amazing deals on this 13Pc Left-Hand Drill Bit Set at Harbor Freight. Quality tools & low prices.
www.harborfreight.com
If you want a real steel drill, try mcmaster.com https://www.mcmaster.com/drill-bits/high-speed-steel-left-hand-drill-bits/
Or grainger.com
You have to have a credit or debit card and purchase online to use either business: they don't talk to amateurs on the phone. Grainger will put orders in will-call at the local store.
Or to avoid a $10 freight charge, use your local fastenal or msc outlet. Hardware stores sell Irwin, which bits are inferior to mcmaster but better than HF. But they don't stock left hand variety.
Use safety glasses when using power tools. Chips fly; bits can break.
The trick to removing a threaded bolt with a LH drill bit is to drill straight counter thread direction into the bolt with a bit 3/5 the size, until the hole is 1/2" deep or so. Then suddenly pull the drill slightly sideways, to grab the bolt and spin it out of the hole.
As the posts on my Pacific & diamondback bikes look welded to the fork, I am dubious about the success of this whole project. If one did drill a welded post out, one would have to make a new post out of rod sawed off to length, then weld it in. Really, another bike frame or fork from a charity resale shop or flea market would be the repair method I would use.
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