Bicycle Mechanics - Broken Headset Bolt

I broke the top-cap bolt while trying to (over-)tighten my headset to remove the fork wiggle.

I realize now that I was cranking it way too hard, but it was removing some of the play and there was still a little play left that I was trying to remove. Also, the spacer was ~5-7mm above the top of the steer tube which as I understand should have been plenty of space for it to get tight assuming I had the appropriate length screw. Now I think the problem may have been that I was using mismatched headset parts. The top cap bolt has Campy Record written on it, However my headset is clearly labeled FSA. I am not sure when this happened as I got it this way from the previous owner. It seemed to work with my old stem but I swapped to a new stem with a larger stack height which is when I broke the bolt.

So I need a new top cap bolt, and they are not a standard size, they're different depending on manufacturer, correct? I am thinking the bolt should be from FSA since that is what is written on the headset? How do I know what exactly to order? The only thing written on the headset is Sealed Stainless and a Pat#.

By the way in case it matters this is a Specialized S-works E5 and the rest of the groupset is campy record.

Thanks for the help!

Go to your LBS with the bike. They probably have the right bolt.... as charmingly non-conformist as Campy is... they still use standard metric turned bolts.

Unless I'm utterly and completely wrong... a standard headset bolt will fix your problem.

There shouldn't be any problem with a different brand top cap, all it does is rest on the spacer. The bolt should be a standard size since I don't see different threadings for star nuts being offered.

Were the stem clamp bolts loosened while you trying to tighten the headset?

Something other than the cap is an issue. Chris King often cites stem faces being out of square so you might look at that. In the mean time, it's just a metric bolt which hardware stores (and bike shops) will have. You should bring a part of the threads from the old one with you so you get the right size as I've seen a couple different sizes used.

Something's really wrong if you broke the bolt. That's a lot of force. Make sure you figutre it out before you break another one.

You should tighten the cap/bolt tight enough so there is no wobble when you apply the front brake and try rocking the bike back & forth holding it by the top-tube/stem. In your case this is so it's tight enough that, when lifting front wheel and angling the bike to one side, the handlebars will flop over to one side.

But no tighter than where you sense resistance in the bars tilting over in the same direction. If you still sense play in the head-set, you have a deeper problem going on. I'd recommend taking it to your LBS and asking them to diagnose your trouble.

Do get back to us. This is a mystery.

I'm with zzyzx on this one. I bet the OP didn't loosen the stem bolts first.

I'm with zzyzx on this one. I bet the OP didn't loosen the stem bolts first.
+1. I'd put money on that as the reason.

yea, that much force seems excessive for some reason. Unless your spacers werent sticking up over the lip 5mm.... maybe they settled after you started tightening, so your topcap was just crankig on the steerer tube?

Here's a tutorial on loose headset tightening if its any help http://www.youtube.com/watch?v=RRFqU07u8DE&feature=related