Technical LEAKY BLEEDER VALVES

Noticed a couple spots on garage floor, wiped them up and floor got real clean; knew it had to be brake fluid. Got midsize GM calipers up front and can't get the bleeder valves to stop leaking past the threads. Any suggestions?

 

Are they newer rebuilds with the crappy Chinese parts? If so, look for some old original bleeders.

 

Dirt in the bleeder screw taper, damaged seat in the caliper or the bleeders are incompatible with the caliper.

 

A 'genius' I know bought some aftermarket midsize GM calipers and had leaks at the bleeder screws also.
When I went to see, he had the Deuce jacked up and was coating the beveled seats with valve grinding compound!
He then screwed them down, and tightened-then-loosened, then repeated the act.
I advised him that 'lapping' had to be done in a consistent back-and-forth constant. He just removed them, and repeated the ill-conceived ritual.
After a series of 5 operations, he had me pump the pedal lightly, as he wiped the open hole for residue; cleaning the screws, he replaced them, with a final bleed.
Doubting Thomas shook my head, but as we checked both sides under pressure, I was surprised.
I was even MORE surprised when I returned there a few days later...he had been driving daily, and there was no sign of subsequent leakage.
Obviously, the mismatch of angles at the seating of the screws and caliper bases were not too severe; OR, they were left with a minute side of 'machining flash' from extended tool usage...(read: #97 & 98 in a succession of "Quality Control: every 100 entities."

I'm not recommending this as a fix. I was merely 'bewildered', (term as applied to the 'metropolitan' male)
I strongly agree with the previous posts, in which 'mismatched', or 'incompatible Chinese parts' faced with GM or 'rebuilt' calipers were introduced.

 

I would try new bleeder screws. Just do one wheel at a time and bleed off a 1/2 quart or so.
If that fails, new calipers may be needed.
How long have the calipers and bleeder been on there, stage if it just developed on a car that's been on the road for a while.

 

Okay, will try the above mentioned. Thought I had this problem solved over a year ago. See if I can locate some originals. Thanks for the help.

 

Teflon Tape will fix them.

 

Speed Bleeders come with a sealant on the threads. Hemi Deuce is right.

 

The taper is what keeps the fluid in there, not the threads. If it's not sealing and the threads are gooped up, fluid will just come out of the center bleeder hole. Might as well just jb weld the damn bleeder in there instead of fixing the problem if you're going to go the hack route. Did no one on this thread read the other thread started by Worn Shoes? Don't half ass brakes.

 

I bought some speed bleeders a while back and had big leaking problems. Removed the bleeders to check them and could see that the taper was not concentric with the screw threads, so they wouldn't seat in the cone of the caliper body. Probably cheap-ass Chinese quality showing through. Was able to turn the tapers in my lathe and true them up to the threads. Everything sealed up fine then.

 

Will try teflon tape if all else fails but I thought the tape wouldn't hold up to the caustic brake fluid.

 

I'd be sketchy on the teflon tape. I use a real thin, carefully applied amount of antisieze.