HELP - Top cap bolt ruined!

sharepointalex

Hi Guys,

It seems I overtightened my top cap bolt (bought a custom kapz one a while back and the supplied bolt is crap!). The head rounded off as a result :-(

I tried the usual, hammering in a flat head bit, torx bit etc going a size up each time, they just spin and make the hole even wider.

I decided to try and drill it out but the head just won't come off! It's just made a dome type effect inside the bolt head now :-(

One option I thought next is an easy out/screw extractor tool? Or is there another way??

Also for next time, is there a better top cap bolt I can get??

Thankfully as the bolt is still stuck fast I can at least use my bike!

Cheers

Baron Greenback

Is there enough if the head left to carefully cut a slot with a Dremel with a cutting tool in it, and then use a flathead screwdriver?

Kneesaway

The top cap bolt does not need a lot of torque as all you are doing is taking the slack out of the bearings before tightening the side bolts on the stem. If you are rounding it off, you are putting way too much torque on it.

You will probably need new headset bearings soon.

imposter2.0

sharepointalex wrote:

Hi Guys,

It seems I overtightened my top cap bolt (bought a custom kapz one a while back and the supplied bolt is crap!).

Haven't heard of anyone else having issues with Kapz. Interested to understand how on earth you managed to overtighten a top cap bolt, given that they're not actually supposed to be 'tight' in the first place?

mikenetic

Sounds like a bit of a mess.

At this point rather that go for an extractor you could keep drilling (carefully!) and complete remove the head of the bolt. That way you can get the cap off, remove the stem and be left with fork released and a length of threaded rod (in effect) to work with.

Options then are to either use mole grips (last resort) or thread two nuts onto the thread. Tighten them against each other, then apply a spanner to the lower one to get the thread released and removed.

Christ knows how it's got so stuck, they shouldn't need much tightening. Do you sweat onto it a lot? Sometimes the salt can corrode stuff into place.

sharepointalex

mikenetic wrote:

Sounds like a bit of a mess.

At this point rather that go for an extractor you could keep drilling (carefully!) and complete remove the head of the bolt. That way you can get the cap off, remove the stem and be left with fork released and a length of threaded rod (in effect) to work with.

Options then are to either use mole grips (last resort) or thread two nuts onto the thread. Tighten them against each other, then apply a spanner to the lower one to get the thread released and removed.

Christ knows how it's got so stuck, they shouldn't need much tightening. Do you sweat onto it a lot? Sometimes the salt can corrode stuff into place.

Thanks - might be sweat from the turbo. To be honest I never knew they only needed to be nipped up slightly - this one was creaking when tightened - oops!!

Will try your method. Quick one though - what is the best way to drill head out? I tried with some fairly big drill bits and it'S just made the head of the bolt wider inside. When will the head just come off?? Is the trick to use a small drill bit in the centre first? I don't want to end up drilling all the way down the centre just want to get the head of the bolt off as you say.

FYI first time drilling a bolt out - in case you couldn't tell!!

imposter2.0

sharepointalex wrote:

To be honest I never knew they only needed to be nipped up slightly - this one was creaking when tightened - oops!!

What do you think is the purpose of the top cap and bolt?

The Rookie

If the headset was creaking presumably you loosened the stem before mashing the top cap, otherwise it didn't matter how tight the top cap was it wouldn't do anything?

airborne_warrior

Knock it further into the fork and fit a new one or even better a headset compression device.

mikenetic

sharepointalex wrote:

mikenetic wrote:

Sounds like a bit of a mess.

At this point rather that go for an extractor you could keep drilling (carefully!) and complete remove the head of the bolt. That way you can get the cap off, remove the stem and be left with fork released and a length of threaded rod (in effect) to work with.

Options then are to either use mole grips (last resort) or thread two nuts onto the thread. Tighten them against each other, then apply a spanner to the lower one to get the thread released and removed.

Christ knows how it's got so stuck, they shouldn't need much tightening. Do you sweat onto it a lot? Sometimes the salt can corrode stuff into place.

Thanks - might be sweat from the turbo. To be honest I never knew they only needed to be nipped up slightly - this one was creaking when tightened - oops!!

Will try your method. Quick one though - what is the best way to drill head out? I tried with some fairly big drill bits and it'S just made the head of the bolt wider inside. When will the head just come off?? Is the trick to use a small drill bit in the centre first? I don't want to end up drilling all the way down the centre just want to get the head of the bolt off as you say.

FYI first time drilling a bolt out - in case you couldn't tell!!

You need a drill bit wider than the threaded part of the bolt. So, try a 6mm. With light pressure and a moderate rpm try to drill down. When you've done enough, the head of the bolt will start to spin as it's been disconnected from the shaft.

Use a light oil on the bolt head to help with cooling during the drilling process. An overheated drill bit will go blunt pretty fast.

noodleman

Not sure how your bike was even rideable with the top cap bolt done up so tight! Even slightly too much tightening makes the steering feel awful. You could try using araldite and glueing a torx head or Allen head in there.

fat daddy

I would be wary of drilling the bolt head off ..... you will be left with either a star nut or expander bung, in the steerer tube with a bolt in place, with no head to try and undo it.

Drilling that out will be a ball ache

I would opt first with Baron Greenbacks idea of using a dremel to cut a new groove you can get a screw driver on 1st .... if that fails then drill it out.

rolf_f

There is a point in a slowly evolving disaster when you should definitely call in the professionals. You've already gone past that point! Take it to a good bike shop - they'll fix it in seconds.

crankycrank

Try undoing the steerer clamp bolts on the stem and then turn the stem anti-clockwise while holding the fork. This may loosen the cap bolt enough so that it unscrews easily.

step83

All else fails if its an alloy steerer take a long bar onto the underside of the star nut and a couple of swift taps should move it up enough to take the tension out of it, or get a set of pliers onto it. Thinking about it most bungs even in carbon frames should be OK with that. I used a long hammer through screwdriver last time, could of hits and it was up enough to undo with your fingers.

Top cap bolts like stems only need about 5nm or torque as in, just nipped up.

imposter2.0

Step83 wrote:

Top cap bolts like stems only need about 5nm or torque as in, just nipped up.

'Just nipped up' is nothing close to 5nm. 5nm is what you put on seatpost bolts.

step83

Imposter wrote:

Step83 wrote:

Top cap bolts like stems only need about 5nm or torque as in, just nipped up.

'Just nipped up' is nothing close to 5nm. 5nm is what you put on seatpost bolts.

Along with stem bolts, brake mounting bolts an pretty much mostbody fixing bolts. Your right though should be enough preload to stop it moving, its Monday they banned coffee stop picking on me!

imposter2.0

sorry

The Rookie

noodleman wrote:

Not sure how your bike was even rideable with the top cap bolt done up so tight! Even slightly too much tightening makes the steering feel awful. You could try using araldite and glueing a torx head or Allen head in there.

Would have had no effect on the steering if the stem wasn't loosened first!

noodleman

The Rookie wrote:

noodleman wrote:

Not sure how your bike was even rideable with the top cap bolt done up so tight! Even slightly too much tightening makes the steering feel awful. You could try using araldite and glueing a torx head or Allen head in there.

Would have had no effect on the steering if the stem wasn't loosened first!

I'm quite aware of that thanks. Was it not then?

The Rookie

From the OP's lack of response to the question, it seems not!

tim_wand

Feck just done exactly this tightening a Kapz into a carbon bung. Over torque wasn't the issue. Basically the Bung in the fork ( FSA ) had a stop at the bottom, It wasn't open ended. Just a light tightening up to this ( Supplied bolt was longer than the thread ) snapped it clean in two. My own silly bloody fault. but end result is new bolt ordered ( Unfortunately it was pivotal to the Kapz design) and Bung drilled out and needs replacing. I ll cut the bolt down next time, but shocking how little force was required to snap the bolt.

step83

Guessing its an alu bolt on that then do you not have any steel ones that'll fit? I used a steel bolt just to be safe.