A pesty leaky bleeder screw is a frequently reported problem in a variety of car forums. But strange enough I’ve seldom seen people sharing their definitive fixes. I’ve struggled with the problem for the last 10 years. 10 out of 12 bleeder screws on all 3 Honda/Acura vehicles in my family developed minuscule leaks sooner or later. Every single time after I bled brakes, some bleeder screws leaked. I’m surprised that few effective fixes could be easily found on the internet.

I’m sharing the fixes I tried over the years hoping to help those who’re bothered by the problem. Meanwhile I appreciate that you share your experience and fixes.

Two Survey questions:

1. How frequently did you experience brake fluid slowly seeping out of the bleeder screw threads after bleeding brakes?
2. How did you effectively fix the bleeder screw leak?

The fixes I personally tried:

1. Tighten the bleeder screw beyond the specified 7 lbf.ft. (I tried up to 16 lbf.ft.)
Results: Hit or miss. More miss than hit. Warning: Overtighten bleeder screw may damage the caliper.

2. Replace with a new bleeder screw. I’ve tried both Honda genuine and aftermarket bleeder screws.
Results: Hit or miss. Sometimes it stopped a leak, but leak often came back and could not be fixed by a new bleeder screw after the next bleeding.

3. Sand/polish bleeder screw tip and clean the mating surface inside the caliper with a #2 Phillips screwdriver bit or wire brush.
Results: Never worked for me.

4. Replace the caliper.
Results: Seems to be overkill just for fixing a minuscule bleeder screw leak. I recently replaced 2 calipers with Raybestos remanufactured (for reasons other than bleeder screw leak) and one of them came with a leaky bleeder screw from the factory.

5. Teflon-tape the entire bleeder screw including the drain hole at the bottom.
Results: This method was a sure fix for me every time because the Teflon tape sealed the thread tight and blocked the drain hole leaving fluid with no space to escape. The downside of this method is of course I have to switch to an untaped bleeder screw before I can bleed again.

6. Teflon-tape the bleeder screw’s threaded area only
Results: I recently tried this method and have not had enough time to verify its effectiveness. This method may work for the following speculations:7. I start to develop a wild conjecture: The bleeder screw actually seals fine with the caliper. The “leak” is the amount of fluid that sits outside the seal coming up and out due to capillary action and will eventually dry out. This conjecture explains several things:If this proves to be true, I’ve been fighting a non-existent problem for the last 10 years!

 

I have never had a bleeder screw weep, ever. New calipers, old calipers, remans, you name it. I have had a number of them plugged that needed to be removed and the obstruction drilled out. No leaks.

Air leaking around the threads while vacuum bleeding, yes. I haven't found a great solution other than not vacuum bleeding.

But I also brake clean the area and the bleeder. Then blow it all dry with compressed air after servicing.

You are probably experiencing the couple drops of fluid left in the bleeder.

 

Thank you for sharing your experience, Rayan! It's very reasonable for the fluid left inside the bleeder to weep out through the threads. So I made sure I cleaned the fluid out before I let it sit overnight to see if it's leaking. I recently replaced the front calipers with Raybestos remans on my Honda Civic. The left front and right rear bleeder screws appeared to be leaking, so I Teflon taped their threads and left the drain holes open. The following day, I felt the fluid levels inside the bleeders rose. So I replaced them with new bleeders. This seemed to have fixed the right rear and the left front still had a tiny amount coming out at the bottom of the thread overnight. I'll leave it alone for now and overserve over the next few weeks.