[krukster86]

So in one of my latest project log videos, I replaced the front brake system on my CB360T (new upper hose, new caliper housing, new piston seal, new pads, new bleed valve). After bleeding the system to build up nice pressure and push out any air, I screwed the bleed valve closed and wiped off any excess fluid. A couple days later, I came back into the garage and saw that I had developed a minuscule brake fluid leak through the threads of the bleed valve. It isn't a huge leak: less than a "drop" that sits at the top of the caliper housing. However, it is annoying since everything is new. (FYI, tightening the bleed valve further did not fix the problem either)

A quick google search indicated that people on car/bike forums recommend wrapping the bleed valve threads with teflon tape to fix this issue. Anyone have experience with this issue and successfully fix it?

 

[jd50i]

Since the bleed port seat does the sealing and not the threads fluid might still seep through.

 

[krukster86]

That is correct. Literally a "band aid" solution that doesn't address the source of the issue.

 

[longdistancerider]

The actual problem is the seat area that the bleeder screw tightens against, probably a small pit of corrosion. A Q tip with valve lapping compound in a drill motor will probably cure it.

 

[krukster86]

The actual problem is the seat area that the bleeder screw tightens against, probably a small pit of corrosion. A Q tip with valve lapping compound in a drill motor will probably cure it.

That sounds about right. I will drain the system sometime and see about performing this task.

 

[krukster86]

Well I am getting really efficient at draining, filling, and bleeding brakes now!

Last night, I got some valve lapping compound on a q-tip and gave the inside of the port (where the screw bottom mates) a couple twirls and cleaned it up. Filled system and bled the brakes. Checked this morning and saw no leaks!

 

[jd50i]