These days , brake bleeding is seen as a black art. But many years ago ( possible 40 years ago) , the latest fad was auto bleed nipples. Simply remove the standard ones and fit these . They worked on the principle that when the nipple was tight, then it behaved as a normal tight nipple. When you wanted to bleed, you slackened off the nipples in sequence and pumped the pedal. The nipple acted as a one way valve. FLUID + AIR was expelled ,and on releasing the pedal the valve shut preventing air entering the system. Of course, you had to look after the master cylinder for level. These days I've only seen them mentioned in motorbike sizes. Anyone seem them or have they been priced out .

They never worked effectively because air was drawn back around the threads on the upstroke.

 

Actually not true, they worked really well to seperate people from their money.

I used them for years with no problems. 

I recall that you had to be careful not to slacken off the bleed nipple too far - just enough to allow fluid flow under fairly hard pressure.

I found normal pressure was enough. Showing my age now, but I fitted them to an old Maxi . Saved marital brake bleeding problems. Cheap at th price of a night fighting.

But a Q for the techies- have bleed nipples gone metric, or are they still part of th old imperial system. Or when did they change?( if they did?)

Edited 4 September, 20205 yr by VWD