Potential dumb question time re bleed nipples

Pointy SV650S.

So I've noticed if I take the bleed nipple cap off the bleed nipple, and then put it back on, I get a small amount of fluid come up through the threads of the bleed nipple. Further I've noticed after going out for a ride and doing some fairly hard braking there's a little damp patch around the bleed nipples on the front brakes. When I say little damp patch I mean as in probably wouldn't even notice it if you weren't looking for it; it just looks slightly moist and there's no evidence of fluid running down anywhere and the brakes feel fine both at the lever and in actual operation. Not sure what to make of it?

Bit of history is that late last year (October timeish) I replaced the bleed nipples when serving the brakes as one was leaking (enough to impact braking performance quite noticeably). Swapped in some EBC HH pads and did the seals at the same time.

It's just bugging me as to whether to worry about it or not.

[Tomor]

Have you tried tightening the nipple to see if it is slightly loose?

Originally Posted by Tomor

Have you tried tightening the nipple to see if it is slightly loose?

Yep, I daren't tighten them any further.

[johnnyrod]

Sound slike there is a bit of grit stuck in there. The seal is made where the conical end of the nipple bottoms (so many inuendoes) in the caliper body, metal on metal. Try putting a piece of tubingon teh end, cracking it open a full turn or so, and squeezing some fluid out. Pull the lever back to the bar, close the nipple, then release the lever, to prevent any air being pulled back in. Odd it's both sides. You do have to do them up but don't murder them.

Originally Posted by johnnyrod

Sound slike there is a bit of grit stuck in there. The seal is made where the conical end of the nipple bottoms (so many inuendoes) in the caliper body, metal on metal. Try putting a piece of tubingon teh end, cracking it open a full turn or so, and squeezing some fluid out. Pull the lever back to the bar, close the nipple, then release the lever, to prevent any air being pulled back in. Odd it's both sides. You do have to do them up but don't murder them.

I had tried that before late last year (not long after fluid was replaced along with work stated in OP), but perhaps didn't give it a full wind out, perhaps just two flats.

I'm okay with accepting that it may just be a bit of fluid caught in the threads of the nipples (with it being just being a small damp patch rather than a full on leak) but I have a track day booked next month so obviously want to be a little more affirmative with things like this.

I'm guessing taking the nipple cap off and then putting it back on is doing a similar thing in terms of forcing fluid up through threads?

I have had this happen a couple of times. Perversely, I found the cure was to actually loosen the bleed valve off (only a tiny amount, I should add!).

Also, I believe you need to be careful with tightening as you can do some damage to the caliper seating if overdoing it.

Originally Posted by sputnik

I have had this happen a couple of times. Perversely, I found the cure was to actually loosen the bleed valve off (only a tiny amount, I should add!).

Also, I believe you need to be careful with tightening as you can do some damage to the caliper seating if overdoing it.

They are tightened up to the point where they feel "very snug" and can't go any further without hanging off the spanner (didn't want to do that).

Interesting that loosening the nipple cured it, how come that would be the cure? Kind of reluctant to try that myself as I just picture a nightmare of either brake fluid making a bid for freedom/air getting acquainted with the inside of my brake lines.

Originally Posted by AkiraSV

They are tightened up to the point where they feel "very snug" and can't go any further without hanging off the spanner (didn't want to do that).

Interesting that loosening the nipple cured it, how come that would be the cure? Kind of reluctant to try that myself as I just picture a nightmare of either brake fluid making a bid for freedom/air getting acquainted with the inside of my brake lines.

As my old mucker Roger Daltrey used to say - I can't explain.

I think it was probably an accidental discovery, probably based on having the same issue, googling the problem, worrying that I had damaged something by overtightening and pathetically thinking that I might somehow cure any damage I might have done by overtightening by loosening the valve after the event! Someone will probably be along shortly to say I am talking nonsense but I can assure you it worked. I'd probably also check the threads are clean too though.

As I say though, it was only a tiny fraction of a turn! Arguably if fluid is visible now then there is already scope for fluid loss/air getting into the fluid, albeit possibly very minor. I don't think you'll run any great risk - worst case scenario, you still have a small leak.

Originally Posted by sputnik

As my old mucker Roger Daltrey used to say - I can't explain.

I think it was probably an accidental discovery, probably based on having the same issue, googling the problem, worrying that I had damaged something by overtightening and pathetically thinking that I might somehow cure any damage I might have done by overtightening by loosening the valve after the event! Someone will probably be along shortly to say I am talking nonsense but I can assure you it worked. I'd probably also check the threads are clean too though.

As I say though, it was only a tiny fraction of a turn! Arguably if fluid is visible now then there is already scope for fluid loss/air getting into the fluid, albeit possibly very minor. I don't think you'll run any great risk - worst case scenario, you still have a small leak.

Experiment during my lunch break (the joys of working from home): tied the brake lever back with some zip ties then called in to a meeting for an hour or so. Went back and had a look and there is the smallest amount of fluid coming out, by smallest I mean tip of your finger nail if that, enough for it to sit in the thread just above the face of the caliper but not for it to spill over and run anywhere. This is on both sides. I suppose the vibrations etc when riding would be enough to make that spread in to a damp looking "patch". Thoughts?

From seeing the results of the above I feel less worried, but still want to check with you more experienced folk. Sounds daft but would a bit of grease where the thread meets the caliper face be okay or is that just masking a problem that might get worse (will it get worse??).

Small bump, any advance/thoughts on this?