Grimeca brake nipple leaking

[j2maria]

I just completed a complete restoration of my Grimeca disk and finished bleeding the system. The brake works fine and is not spongy. However, I notice that each time I press the brake lever, some brake fluid escapes from the brake bleeder nipple, even after ensuring the nipple is tightened all the way down. It does not leak through the treads but through the bleeder hole that is usually covered by the rubber bung. Any ideas why this would happen? Did I overfill the reservoir?

Joe

[EVguru]

There should be a ball bearing under the nipple. This makes the seal into the seat rather than the nipple.

The ball could be missing or not seating properly.

[j2maria]

Aaaah! That's it! I have a spare ball bearing rolling around my tray and having never seen a brake nipple with a ball bearing stopper did not realize it came from the caliper! I was scratching my head trying to figure out where it came from

Thanks very much, EVGuru!

Joe

[j2maria]

>>>There should be a ball bearing under the nipple. This makes the seal into the seat rather than the nipple

Can I just remove the nipple and insert the ball bearing or do I need to disassemble the caliper completely?

I assume that if I raise the caliper over the level of the brake reservoir nothing should run out and minimal bleeding would be needed? However, I can't figure how, if a ball seats to seal the nipple, any bleeding is possible as brake fluid would not be able to get past the ball seal.

Joe

[3potjohn]

The brakes will bleed OK by loosening the bleed nipple usual.I didn't know about the ball bearing either.One was corroded so would not seal. I should think you can whip out a bleed nipple and replace the ball, and just hose off any dribbled brake fluid.Then may have to bleed again. Mind the fuel tank when refilling and bleeding as the brake fluid can be ejected from the master cylinder when the lid is off.

[EVguru]

Can I just remove the nipple and insert the ball bearing

Yes.

I assume that if I raise the caliper over the level of the brake reservoir nothing should run out and minimal bleeding would be needed?

Yes.

However, I can't figure how, if a ball seats to seal the nipple, any bleeding is possible as brake fluid would not be able to get past the ball seal.

The nipple has a cup on the end for the ball and a crossdrilling behind the end for the fluid.

[j2maria]

As it turns out, inserting the ball bearing was a non-event. I unscrewed the nipple with the caliper still on the leg, no brake fluid squirted out, I dropped the bearing in and screwed the nipple back on, and the lever was just as firm as before! As you pointed out, Paul, there is a small hole cross-drilled at 90deg. to the thread that allows bleeding past the bearing, which actually sits under a little dimple on the nipple.

Thanks all for the help.

Joe