Snapped Pinch Bolt. Help!

[Knapdog]

Just as I was about to report back on how pleased I am with my new Bitubo rear shocks I thought I'd go through the sequence of loosening the pinch bolts, torque-ing up etc,  the front axle as I'm still not 100% happy with the front suspension.
Well I've done this so many times I could do it blindfold.
I set my torque wrench to 22nm and tightened up the inner bolt without a problem but, for whatever reason, the right one snapped. I'm baffled to how this might have happened.  I remember thinking that the torque should have kicked in by now.... and then, the dreaded snapping sound.
All I know is I'm gutted.
Here it is.... What do I do? Suggestions appreciated.
Presumably I can I still ride the bike until the next tyre change  but it has to be sorted.



I can only think of trying to drill a slot for a screwdriver into the "back" end of the bolt and trying to screw it out but that would involve a fair bit of "slot" accuracy.

[The emperor has no clothes]

https://www.amazon.com/Irwin-Industrial-Tools-53535-Extractor/dp/B00004YOBF/ref=asc_df_B00004YOBF/?tag=hyprod-20&linkCode=df0&hvadid=309802506143&hvpos=&hvnetw=g&hvrand=3087443766046037695&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9030351&hvtargid=pla-434200247990&psc=1

[Bagger John - #3785]

Left-hand drill bits in a slow-speed (battery operated) drill are another option.

[idaida98]

I second the left hand drill bits.

[hubcapsc]

Getting your particular stuck bolt out looks like it might be a hard job, but
I agree with trying some kind of extractor. I had to ... extract ... a couple of
bolts a while back. I tried a couple of extractors... I remember one that
you tapped with a hammer and it made a bite into the stuck bolt and
held on well enough for me to turn the bolt out...

I guess you can't take your wheel off (have you tried?)... I bet it would work
good to take that fork off, work up some kind of jig and drill the broken
bolt out in a drill press with successively bigger drill bits. I made a
mess of trying to drill out a bolt by hand with a hand drill, but a
jig and a drill press would be much more foolproof.

-Mike

[RonW]

"Presumably I can I still ride the bike until the next tyre change  but it has to be sorted."

Wouldn't you have half the holding strength or double the stress on the single pinch bolt? I'm not an expert though but you might have to extract the stub and replace the bolt.

[old2soon]

Getting your particular stuck bolt out looks like it might be a hard job, but
I agree with trying some kind of extractor. I had to ... extract ... a couple of
bolts a while back. I tried a couple of extractors... I remember one that
you tapped with a hammer and it made a bite into the stuck bolt and
held on well enough for me to turn the bolt out...

I guess you can't take your wheel off (have you tried?)... I bet it would work
good to take that fork off, work up some kind of jig and drill the broken
bolt out in a drill press with successively bigger drill bits. I made a
mess of trying to drill out a bolt by hand with a hand drill, but a
jig and a drill press would be much more foolproof.

-Mike

         THIS and maybe a heli coil. My road peg was messed up after I went down in . Had to repair the totaled threads! Drill tap and heli coil!  Primo repair!  RIDE SAFE.

[Chrisj CMA]

In this case you have a couple extra options since the threaded hole is open at the rear. Penetrating oil. Heat and maybe non reverse extraction from the back side

Ya, I’ve never broken a bolt on a motorcycle that I wasn’t tightening with a torque wrench. I don’t use a torque wrench on those pinch bolts. Firm is all you need.

[Speedy Coop]

That bolt should come out easily for you since you have had it loose already.

[Jess from VA]

Ride over to a machine shop, and look wistful.   

Calling around may be easier, but it's also easier to say no to the phone.

I might get the replacement bolt first. 

[crow]

Use what's called a... Transfer Punch...  It will put your center punch  dent ,for drilling, absolutely dead nuts center.

[Knapdog]

Have woken up this morning to all these helpful replies.
Thank you all. This is such a great forum.
Since I can get at the snapped bolt from the back, I'll attempt drilling and hopefully it will "unscrew" all the way out to the front.
Since it is in tight and effectively acting as normal, I reckon I can ride it until I sort it.
My torque wrench has a minimum setting of 30Nm. To set it at 22Nm I slacken it off to below the actual minimum setting. I wonder if this has somehow deactivated the torque feature on this occasion even though it has worked before.
BTW, set of four pinch bolts already ordered.

[Skinhead]

If you plan to continue using a torque wrench, get one with a lower range for the small bolts.  You bought capacity wrench was made to be used at that loss of a torque and will be inaccurate.

[Knapdog]

If you plan to continue using a torque wrench, get one with a lower range for the small bolts.  You bought capacity wrench was made to be used at that loss of a torque and will be inaccurate.

Yup. Thought I might have been taking a chance. Thank you.

[psckam]

Correct me if I am wrong but the pinch bolt works by pinching, in this case axle. The head of the bolt only threads into the 'back' half of the fork, which to my way of thinking means that, sans bolt head, no pinch affect? No?

[hubcapsc]

Correct me if I am wrong but the pinch bolt works by pinching, in this case axle. The head of the bolt only threads into the 'back' half of the fork, which to my way of thinking means that, sans bolt head, no pinch affect? No?

I think you just corrected all of us    ...

-Mike

[98valk]

was that a clinker type torque wrench?, which needs to be calibrated every yr if used a lot or a digital type wrench? many bolts are broken by a clicker.  reason I don't even own one.
strictly beam type torque wrenches for me, ftlbs and inlbs, and a mechanical dial type torque wrench for over 150ftlbs as needed on my F250.

[Knapdog]

Correct me if I am wrong but the pinch bolt works by pinching, in this case axle. The head of the bolt only threads into the 'back' half of the fork, which to my way of thinking means that, sans bolt head, no pinch affect? No?

You're absolutely right. I stand corrected. Have just checked. There is no thread in the "opening half" of the fork.

[Knapdog]

Success. It's out!
I started drilling but it was only when I put the "hammer" on did it make a move, though I did use copious amounts of Penetrating Spray plus heat.
Once I'd got a thin edge to the drilled part I hammered in a screwdriver to make a sort of "flat" then screwed it out to the front....



The only thing now is I've noticed the other pinch bolt is tight as well so I'm preparing myself for shearing that one if I decide to take it out.

[98valk]

Success. It's out!
I started drilling but it was only when I put the "hammer" on did it make a move, though I did use copious amounts of Penetrating Spray plus heat.
Once I'd got a thin edge to the drilled part I hammered in a screwdriver to make a sort of "flat" then screwed it out to the front....



The only thing now is I've noticed the other pinch bolt is tight as well so I'm preparing myself for shearing that one if I decide to take it out.

 

[Bagger John - #3785]

The only thing now is I've noticed the other pinch bolt is tight as well so I'm preparing myself for shearing that one if I decide to take it out.

I would soak the remaining bolts with penetrating oil, carefully extract them then clean each and chase the holes with the appropriate tool.

Then ask yourself why they're tight. Hint: Galvanic action is a thing.

I use a bit of anti-seize or NoAlox on fasteners which are subject to moisture ingress, and derate the torque values a bit (say, 1 ft-lb) for such a fastener.

As an aside, I've never broken a bolt with a clicker torque wrench - but I use the right one for the job at hand and have a number of them.

[longrider]

Still don't know why so many use torque wrench on such small bolts/nuts.  Exhaust studs etc.  Too many variables trying to snug them up until they snap.  Just ease them up with the appropriate wrench by hand and get em snug  no more. 

[Bagger John - #3785]

Still don't know why so many use torque wrench on such small bolts/nuts.  Exhaust studs etc.  Too many variables trying to snug them up until they snap.  Just ease them up with the appropriate wrench by hand and get em snug  no more. 

A properly cleaned threaded fastener that's not been metallurgically compromised will take its rated (specified) torque without breaking. The engineers who designed our bikes (along with other products) understand such things as material science, required clamping force, resistance to loosening and numerous other mechanical engineering principles. They arrive at torque values for a given fastener and application based on these principles.

Caveat: As stated above, this implies that ALL parts in the force chain are in optimum shape. If they aren't, clean and/or replace.

I own clickers that go down to 10 INCH-pounds, and if I need to go lower I have access to equipment which can measure down to a quarter of that.

Something else to remember: One person's "snug" isn't the same as another's. I routinely read accounts of people breaking bolts or studs off because they over-tighten them - when in fact the proper tool would have saved the fastener.

[Knapdog]

Some interesting replies.
With Penetrating Oil I've now unfastened the other bolt.
From now on I'll snug them up by hand unIess I get around to purchasing a torque wrench suitable for lower measurements.

[RP#62]

One other caution, if you torque a lubed fastener (a al antiseize) to the dry torque rating, you'll be overtorquing it). 

-RP

[Skinhead]

The remaining boy now has double the clamp load on it.  To remove it you should first install a replacement bolt to take some of the load off the other bolt, and then back then both of in steps a little at a time.

[Bagger John - #3785]

One other caution, if you torque a lubed fastener (a al antiseize) to the dry torque rating, you'll be overtorquing it). 

-RP

Hence, the derating bit I mentioned.

Had a long reply on this very subject typed up but I think the dog ate it. In short: When I use anti-seize or liquid thread locker on a fastener I derate the specified torque value by either 5% or per the compound's material properties sheets.

[Chrisj CMA]

Seems once a year or so this topic comes up. For you old wrenches that are comfortable in your ways and are experienced this is not for you. For the guys on their first bike or two or just starting to work on their own bikes. This is very important.

Pay attention and learn what a fastener is there for. What is it’s job? 80-90% of the bolts on our bikes don’t need to be tightened with a torque wrench if you understand a few things. Also practicing with a torque wrench and a socket wrench together on some random parts in your shop will give you an idea of what various torque settings feel like.

The larger the bolt the higher the torque generally. Smaller bolts need less. With practice you can take the size of the fastener compared to what it’s job is and decide how tight you should make it in the event you are away from your torque wrench. Once you know what approx 10, 20, 30, 50 pounds feels like you can competently work on darn near all parts of your bike without a torque wrench.

[old2soon]

Seems once a year or so this topic comes up. For you old wrenches that are comfortable in your ways and are experienced this is not for you. For the guys on their first bike or two or just starting to work on their own bikes. This is very important.

Pay attention and learn what a fastener is there for. What is it’s job? 80-90% of the bolts on our bikes don’t need to be tightened with a torque wrench if you understand a few things. Also practicing with a torque wrench and a socket wrench together on some random parts in your shop will give you an idea of what various torque settings feel like.

The larger the bolt the higher the torque generally. Smaller bolts need less. With practice you can take the size of the fastener compared to what it’s job is and decide how tight you should make it in the event you are away from your torque wrench. Once you know what approx 10, 20, 30, 50 pounds feels like you can competently work on darn near all parts of your bike without a torque wrench.

 
               

                   ^^^THIS^^^
                       

             
           

[da prez]

Relate this to torquing a head on an engine . Progressive torquing. Torque to 25% of the value on all fasteners. The n to 50 and then 75. Do final torque. For the hair splitters , you need more than 10% to move a fastener.
 What this means is if you are at 90 lbs torque  ,torquing to 100 will not happen. Drop to 80 and then final torque of 100 can be achieved. As I was getting out of the trades , dial torque was comming in play.
                 da prez

 

[crow]

One other caution, if you torque a lubed fastener (a al antiseize) to the dry torque rating, you'll be overtorquing it

Correct, all torque values, on charts, are clean threads, wiped dry.

[Led]

Also "torqued" bolts have a shelf life.  Torque them TOO many times, they will eventually snap.  They stretch a just a bit, after every torqueing done to them.

I know a lot of car engines where the head bolts are called out as ONE TIME use only!!  Even though no one ever follows this. They want you to use brand new hardware each time.

[RonW]

A torque-to-yield bolt (TTY).