Do the Miata brake calipers take a special size thread bleed screw? Mine seem loose in the threads and leak once tightened.
The calipers are reman from the flap. The bleed screws are quite shiny. Thinking the thread pitch might be wrong.
Does Teflon tape work on this?
Thanks
Don't use Teflon tape.
It doesn't take a special thread, but it does need the correct thread. What year/generation and which end?
Thread specs here. That's Teflon paste in the picture, not tape :)
1990 1.6 calipers
Both front and rear actually
The threads don't really have a whole bunch to do with sealing the bleeder. There is a hole in the bottom that the tapered end of the bleeder screw seats against. The seat is probably damaged. Whine at the store, get another caliper.
@ OP. Bad rebuild take them back and get new replacements. Yes you could probably fix it with the correct bleaker screws but I would make it there problem as it indicated to me there was no testing done by the rebuilder.
Since calipers tend to rust, I wonder if there's some pitting on that sealing surface in the caliper?
Keith Tanner said:Thread specs here. That's Teflon paste in the picture, not tape :)
Also +100 for Speedbleeders. They are too cheap not to get and help quite a bit.
One thing I have learned though is that worn threads can also make it impossible to get a great bleed, so slathering on the paste helps more with preventing air ingress when bleeding than fluid egress when braking. Still, reman calipers might have sloppy threads that, even if they do seal when tightened down, might make it hard to get a very good bleed even with a bunch of paste.
First choice is to try to get free replacements of the calipers. But if that doesn't work, you can try the bleeder screw repair kits that are sold in most auto parts stores. Cost approx $7/ea. They're similar to oversized oil pan drain plug replacements.
Bleeders don't seal at the threads (except during bleeding.) They seal at the seat. If the bleeders tighten then they're probably the correct thread. If they tighten but still leak then either the seat or the face of the bleeder is damaged. If they're new remans then whatever the issue is you should just take them back.
You might try replacing it/them with genuine Mazda B screws. If that fails, then return the calps as mentioned above.
The calipers have been on the car for a couple of years so no returning these.
I'm going to try some bleed screws from other miata calipers i have laying around with some Teflon paste. Hopefully those are the correct thread pitch and fit better.
Thanks.
If those don't solve it then try brand new OEM B screws. Also be sure to torque them to specs (I'm sure you're doing this, but mentioned it just in case). BTW, I very much prefer using a good beam type T wrench when it comes to lower torque specs.
amg_rx7 (Forum Supporter) said:The calipers have been on the car for a couple of years so no returning these.
I'm going to try some bleed screws from other miata calipers i have laying around with some Teflon paste. Hopefully those are the correct thread pitch and fit better.
Thanks.
Again. The thread sealant on the bleeders Keith posted are so that they don't leak air when using them in bleeder mode. In your situation all tape is going to do is possibly hide the leak for a bit. Don't put any sealant on there, tape or otherwise, until you've actually fixed the problem. Once you have bleeders that seal then you can add the tape if you're vacuum or pressure bleeding that getting air leaks past the threads while the bleeder is open.
APEowner said:amg_rx7 (Forum Supporter) said:The calipers have been on the car for a couple of years so no returning these.
I'm going to try some bleed screws from other miata calipers i have laying around with some Teflon paste. Hopefully those are the correct thread pitch and fit better.
Thanks.
Again. The thread sealant on the bleeders Keith posted are so that they don't leak air when using them in bleeder mode. In your situation all tape is going to do is possibly hide the leak for a bit. Don't put any sealant on there, tape or otherwise, until you've actually fixed the problem. Once you have bleeders that seal then you can add the tape if you're vacuum or pressure bleeding that getting air leaks past the threads while the bleeder is open.
Unfortunately (or maybe fortunately depending how you look at it :) ), this is on a race car so I can't really take it out for a test drive to see if different bleed screws fix the problem. Track entry fees are expensive and I don't want to discover that the screw change didn't completely fix the problem. So when I install different bleed screws, I will take a hard look at how the screws fit and then add some Teflon paste after test fitting or install new calipers which hopefully don't have the same problem.
YMMV 
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