stevage

My rack bolt head broke off. There's maybe 7-8mm of screw remaining poking out. I hacksawed a slot in it to then use a screw driver, but it's stuck pretty firmly.

The web has much advice about welding things onto the screw (when it's not giving advice that involves dremels and other tools I don't have). So I was thinking I could put some superglue into a nut, screw it on, let it set, then try to unscrew that.

It's an aluminium frame, and (I assume) a steel bolt.

Anyone tried this? Any thoughts?

Bill Kapaun

Can you remove all the other mounting bolts and get the rack off?
Then you could grab the stud with a vise grip pliers and screw it out.

Superglue won't hold.

Shimagnolo

In my experience, superglue is worthless unless you are gluing skin to skin.

stevage

I did that, but I can't get enough grip on the thread with pliers. I don't have any locking (vise-grip) pliers, but maybe time to think about getting some.

woodcraft

Heating the bolt with a torch will help a lot,

if you can do it without messing up the frame paint.

DrIsotope

PB Blaster + Vise Grips

jyl

If you have 7-8 mm of exposed bolt (alnost a centimeter), you should be able to clamp that with visegrips and turn it. Soak with penetrating oil overnight. If the threads aren't buggered up, you might first try threading on two thin nuts, tightening them against each other, and turning the inner one.

Jseis 

Al and steel. Gag. That corrosive union forms aluminum oxide which is essentially sandpaper grit. As you turn the steel thread the aluminum oxide provides friction augmented by the...rusting steel. Getting the rack off and soaking in Aircoil or similar lubricant is good but ultimately it's a battle of force over friction. I'd alternate between mildly heating the frame and cooling the nut, to vice versa and keeping heat under 300 degrees to not to mess with the Aluminum. I've used a hot wrench to solve many farm machinery issues but bike stuff is NOT built like farm iron. I'd go through that soak and then heat/cool cycle a few times then try a socket with a very good sharp and tight fitting screwdriver bit and preferably one where you could lightly clamp the frame and socket driver head in a vise to keep the screwdriver bit from jumping out of the slot you cut. Then apply some slow force. Would take much to know if your...screwed. All you are trying to do is to get that damn thing broken free so you can then work it back and forth to get it out.

If that didn't work, I'd drill and try an easy out (why not?) and if that didn't work, I'd drill a bit more and re-thread the Al rack. I rarely give up on such a problem and it'd say..mostly successful if patient with ...some spectacular failure. My guess is that if the head of the thread (bolt) twisted off..well that's a lot of force and freeing up the remaining thread with a screw slot is really dependent on seriously reducing the friction and that is going to be tough. A small air hammer might work if set real light but it'll likely tear/damage the screw slot.

PS, use Never Seize when reassembling.

CliffordK

If you have 7-8mm of bolt sticking out, that is more than enough to grab it with vice grips.

Pick up a pair of new, good, sharp vice grips, and you'll be able to pull it out quickly and easily. It doesn't have to be a very big pair.

dsbrantjr

Genuine Vise-Grips, not knock-offs. If that fails get a left-handed bit set from Harbor Freight and drill out the stub. https://www.harborfreight.com/quickvi...ndex/id/10830/

Retro Grouch 

My recommendation.

dedhed

While turning with the vise grips if you can see the other end, verify it's turning and not snapping the bolt off closer to the frame.

If there is enough space 2 thin nuts can be jammed and the lower used to back it out.

fietsbob

5~8mm sticking up? +1 grab whats left with vise grips and Unscrew it.

Or have A Bike Shop do It For You.

CliffordK

I usually find myself trying to catch 1-2 mm of a screw or bolt with the vice grips and can usually get it. I do like the genuine vice grips, but they've now started importing them. There are some good knockoffs. I think Sears made some.

Over time, the teeth at the corners get rounded and they no longer grip short stubs.

Gresp15C

In addition to vice grips, you could also thread two nuts onto the bolt, jam them together, and then remove the bolt with a wrench. If you can get the bolt to move in either direction, then you have a chance of working some oil into the threads.

ltxi

Ain't no glue gonna work to do what you want. Not even JB Weld.

Plimogz

+1 Maybe time to get a pair of good vice-grip pliers. A supremely useful tool, IMHO.

With a small caveat: I have some genuine, old-school, made in the USA, Vice-Grips which were given to me but originally bought before my time. I have also purchased some more recently, which were made overseas (China, I think) and they are obviously not made to the same standards, no matter what Irwin says about their QC -- The newer vintage tools' jaws often do not close as accurately against each other, they usually have more slop in their pivot points as well -- My point is, if you are buying a new Irwin Vice-Grip, take the time to compare and contrast between whatever stock you are choosing from, some are definitely nicer than others, from what I have seen, given the variability within their manufacturing tolerances and whatnot.

stevage

Oh! That's so clever. I wish I'd thought of that before I started mangling the top of the bolt :/

Dan Burkhart 

My experience as well. I've been disappointed with the newer versions of Vice Grip. My wife was formerly employed by Rubbermaid, the parent company of Irwin tools, and I got some good deals on them at the employee store, but they are not up to the old standard.

Bill Kapaun

Vise grips work much better than vice grips.

Dan Burkhart 

Ha! Ya got me.

CliffordK

A week and no response from the OP whether the bolt is out or still stuck?

Plimogz

Too true!

Crankycrank

Not here they don't.

Police Arrested 144 Prostitutes & Gangsters In Singapore Biggest Vice">

rmfnla

Wrong sub-forum; this belongs in Road Cycling...