Headset Leaking Brown Gunk
 

My FSA IS-2 supposedly sealed bearing threadless headset has been leaking some brown liquid out around the top of the head tube. It looks like thick rusty water, but could be a dilute grease or something. The frame is titanium and the fork is carbon, so neither of them should be rusting. The headset bearings seem perfectly smooth and solid. The bike is not quite a year old. I haven't been riding in the rain or wet, other than the occasional puddle. Could be sweat, I suppose, though I don't know how it would get that much inside the head tube. There is enough of the liquid leaking out that it was dripping off the frame onto my knee and leg. I suppose I should disassemble the headset and see what's going on inside there, but this seemed rather odd to me. It doesn't seem like there should be any liquid inside there to run out. Has anyone else seen this? Should I be worried about the bearings?

The brown gunk is probably combination of water and grease; the water is probably the result of condensation inside the frame

johnniebob, Disassembly is easy enough and the only way to know what's going on.

Brad

Do you store it inside?

Let us know what you find.

Very few (if any) headset makers use brown grease, so you're seeing a mix of grease and water, and the brown color is because of rust. One reason that many bike mechanics prefer a lighter colored grease is that they can use the color as an indicator of condition, ie dirt or rust.

If it's coming off the lower bearing, you're seeing the result of water spray off the front wheel getting blasted into the lower headset assembly. This is common on some headsets that lack a decent seal or long skirt there. The bearings seal isn't adequate to keep water out, so if it's sprayed into the area, it'll get to the bearing.

You can improve things, but how you do it depends on the headset. On some, you can fit a large rubber band (I use the one that comes on Broccoli) around the lower headset assembly so it closes below the crown races. On others, a disc pressed on below the crown race reduces spray entry, and on some headsets you can trap an O-ring between the crown race and heat tube or bearing skirt.

Either way, you're choice it to improvise a better seal, or drop the fork, and inspect, and grease the lower bearing every 6 months or so.

It could also be water mixed with copper anti-seize grease, which is often used on Ti frames.

It sounds like the OP is using an integrated headseat. If so, I think he should be able to replace the lower bearing and crown race with IS-compatible parts from any manufacturer, e.g. a Cane Creek 110 stainless bearing and fork crown race with a sealing gasket around it.

Also, I believe a common trick in the MTB/cyclocross community is to take a section of a large-diameter inner tube and stretch it around the lower fork crown and head tube interface.

Sealed bearing is sometimes a term of convenience rather than functionally accurate, often misused/misapplied to cartridge bearings. The inner tube trick works well, and it's good for all-weather commuters also - I used that back in the 70's. Put a thin layer of grease on the inside of the tube for better sealing.

If the frame is titanium and the fork carbon (he didn't say of the steerer is steel or not), and assuming fork is all carbon, as the OP asked, where would the rust come from?

Could be flux also.....shouldn't be,but it could be.Should have been purged with gas but that doesn't mean it was.

Thanks for all the suggestions. In response to some of the questions:

I believe the steerer tube is carbon, not absolutely positive. Guess I'll have to take it apart to look.

I store it in the garage, so it is "inside" out of the rain, but not in heated or cooled space. Could be condensation I suppose.

The brown discharge is coming only from the upper end of the head tube, not the bottom end.

Yes, it is an integrated headset (FSA IS-2).

And yes, the question about if the fork is carbon and the frame is titanium, where would rust come from, is exactly what I was wondering. The only steel in there should be the bearings. Can't imagine they would produce enough rust for it to be running down my leg.

I don't think you can use flux with titanium..

There are paste fluxes for welding and brazing Ti.

Bearings.

I had exactly this problem on my Litespeed with an aluminum steerer. The top bearings were shot and lots of brown crap coming out. Not sure why the top, I rarely ride in the rain or wash the bike with a hose. The bottom set were indexed a bit, but in reasonable shape otherwise.

Hmmm. Interesting. So, the brown gunk was probably bearing grease? Or a mixture of grease, dirt and rust or something?

Sounds like I'd better find time to take it apart and check the bearings.

I finally took the head set apart to see what was happening. The brown appeared to be rust, which was coming from the outside of the housing of the sealed bearing. The bearing itself seemed fine: smooth, tight and sealed, no excess play, nothing loose. The outside of it, where it seats in the fork, was lightly covered with rust, to the point that I could not read, or even find, the etched labeling on it. The stuff oozing out the top of the head tube seemed to be a rust colored slurry of the assembly grease, rust, and sweat. There was a lot of scale inside the stem and spacers, presumably dried from sweat dripping on the top of the stem and running down inside. The steerer tube is indeed carbon fiber, so the only steel anywhere in the head tube was the bearing housing. Comparing the top bearing to the bottom bearing, the top bearing housing was much rustier than the bottom one, again presumably from sweat getting to it. The assembly grease on the bottom bearing was not rust colored. It was the translucent traditional "grease color". I'm thinking maybe I should do something to seal the pre-load cap so it doesn't collect sweat so much.

That's the headset's way of saying "Relube me, please." Condensation gets in there, and by default, dirt and grime, and when it mixes with your lubricant, it breaks it down. Time to clean, OP.

Early on in this thread, I suggested that the seepage was rust stained grease, and mentioned that rust colored greases aren't used on bikes.

I only bring it up again to remind folks that if you see rust stains, don't look for complicated explanations. Rust stains usually mean rust.