[Up4speed]

I flushed the brakes for the first time on my M2 Comp, and torqued the brake bleeder bolts to 10NM, like most calipers. Unfortunately, it seemed like the bolts were very slightly weeping some brake fluid. I looked in the shop manual and it said 18NM for Brembo brakes, which is tighter than I expected (but that page was very confusing since it gave different torques for different calipers, so I feel it was generic). I started to torque them to that, but it felt like I was turning them way more than it took to loosen them, so I chickened out. I didn't want to strip or ruin anything. I stopped and loosened the torque wrench until it clicked without tightening the screw more, and I was at about 16.2 NM. It seems like they aren't leaking anymore.
The thing is, I am very anal, and want them torqued to the "proper" torque as per the manufacturer. Can somebody please help me out with the proper torque?
PS- I did the brake fluid flush on my wife's 540i Xdrive with the M Package on the same day, and had the same exact results (weeping), but only on the fronts. With the M package, it seems like the fronts are Brembo (but slightly different than the M2), but the rears look a little different, they seem to be a more standard design with a sliding carrier.

[doughboy]

They do dribble a bit from inside the bleed bolt, just wipe it up with a paper towel. What angle is the bleed valve at?

If it was really weeping when standing then it would spray out when you applied the brakes...

Never torqued one in my life, just nip it up by hand with a small spanner.

[Up4speed]

Originally Posted by doughboy

They do dribble a bit from inside the bleed bolt, just wipe it up with a paper towel. What angle is the bleed valve at?

If it was really weeping when standing then it would spray out when you applied the brakes...

Never torqued one in my life, just nip it up by hand with a small spanner.

I never used to use a torque wrench on them either, and did it on dozens of vehicles. Until I did it on a Ferrari with the Brembo brakes, and it was leaking. I looked up the spec, and it was 14 ft/lbs! I thought it was way too tight, but when I followed the spec, I never had another problem. So that's when I decided that the right thing to do was to look up the spec each time (since it varies on my vehicles from 6 ft/lbs to 14 ft/lbs). I like to do things as per factory manual when possible, but on this car, the manual is very vague for some reason. It breaks it into caliper types and seems very repetitive as well.
Take a look at the factory manual specs:

[doughboy]

It seems alot for a small steel screw in soft alloy.....

Better make sure you're torque wrench is a good small (1/4") low range one, not using a 200lbft one turned down to 17...

[Maynard]

Remember that 18nM is about 13.3 ft/lbs, for those of us who aren't down with the metric system. Thx for posting the specs.

[///MPhatic]

Pure fear tightening these. I never do them to spec. I tighten, check for weeping after a few days, then tighten a bit more if necessary, but it usually isn't because I note the clock position before loosening, and always put it back exactly where it came from. I even made a specific nipple wrench (the one in the middle) so I didn't have to rotate it from side to side because that changes the clock position.

[Up4speed]

Originally Posted by doughboy

It seems alot for a small steel screw in soft alloy.....

Better make sure you're torque wrench is a good small (1/4") low range one, not using a 200lbft one turned down to 17...

Yes, I have a very good 1/4" ratchet

[Up4speed]

Originally Posted by ///MPhatic

Pure fear tightening these. I never do them to spec. I tighten, check for weeping after a few days, then tighten a bit more if necessary, but it usually isn't because I note the clock position before loosening, and always put it back exactly where it came from. I even made a specific nipple wrench (the one in the middle) so I didn't have to rotate it from side to side because that changes the clock position.

I first tried the clock position, and it wasn't even close to sealing (Maybe when new, they rely on the paint to seal it, who knows). Even torquing to 10NM initially (a little more than 7 ft/lbs I think) which is comfortable for any bleeder valve, it was way more than the clocked position. That's why I'm a little confused as well. And it still seemed to weep.

[///MPhatic]

Originally Posted by Up4speed

I first tried the clock position, and it wasn't even close to sealing (Maybe when new, they rely on the paint to seal it, who knows). Even torquing to 10NM initially (a little more than 7 ft/lbs I think) which is comfortable for any bleeder valve, it was way more than the clocked position. That's why I'm a little confused as well. And it still seemed to weep.

That's definitely weird.

I'll also say that if you just pull the bleeder tube off and replace the rubber nipple cover it'll weep out what was in the top of the nipple over time, so you have to clean the area really well, then dab the top of the nipple with a paper towel or rag until all of the brake fluid is gone before replacing the rubber cover.

[doughboy]

Originally Posted by Up4speed

I first tried the clock position, and it wasn't even close to sealing (Maybe when new, they rely on the paint to seal it, who knows). Even torquing to 10NM initially (a little more than 7 ft/lbs I think) which is comfortable for any bleeder valve, it was way more than the clocked position. That's why I'm a little confused as well. And it still seemed to weep.

It will weep from the open ended vent valve, especially if it is not vertical.

Do you mean static weep or weep when brakes are applied and held? Two very different things.

[Up4speed]

Originally Posted by ///MPhatic

That's definitely weird.

I'll also say that if you just pull the bleeder tube off and replace the rubber nipple cover it'll weep out what was in the top of the nipple over time, so you have to clean the area really well, then dab the top of the nipple with a paper towel or rag until all of the brake fluid is gone before replacing the rubber cover.

I did that

[Up4speed]

Originally Posted by doughboy

It will weep from the open ended vent valve, especially if it is not vertical.

Do you mean static weep or weep when brakes are applied and held? Two very different things.

Not sure. At first, I thought it was weeping from sitting. Then I washed the wheels/calipers with soap and water and took the car for a nice long drive. When I got home all were dry except the driver's side rear. It looked like there was a shine on the hoop that holds the nipple cover on. I touched it with a paper towel and confirmed that it was a little brake fluid. That's when I nudged the bleeder valve a little more with a wrench, and it seems good so far.
It is definitely not behaving like the other dozens of times that I've done this job. That's why I'm searching for a definitive proper torque.

[CSBM5]

You can always try replacing the bleed screw (aka "ventilation valve") with a new one as they aren't too expensive: looks like $9.72 discounted. I'm surprised they're this expensive now, but then again part-flation I suppose, as the part is widely used across many models.

Were the screws very tight when you started working on it? Many years ago on an E46, a BMW service department way, way over-tightened the bleed screws (under warranty/maintenance), and when I later bled the brakes and normally tightened the screws, they weeped. I had to end up tightening them almost as much to stop the weeping. I replaced the screws and that helped a bit, but I assumed the seat in the caliper where the screw face interfaces had some damage. From then on for many years, they (both rear calipers) required very high torque to stop the weeping, but I could always just crank them down and get by.

[Up4speed]

Originally Posted by CSBM5

You can always try replacing the bleed screw (aka "ventilation valve") with a new one as they aren't too expensive: looks like $9.72 discounted. I'm surprised they're this expensive now, but then again part-flation I suppose, as the part is widely used across many models.

Were the screws very tight when you started working on it? Many years ago on an E46, a BMW service department way, way over-tightened the bleed screws (under warranty/maintenance), and when I later bled the brakes and normally tightened the screws, they weeped. I had to end up tightening them almost as much to stop the weeping. I replaced the screws and that helped a bit, but I assumed the seat in the caliper where the screw face interfaces had some damage. From then on for many years, they (both rear calipers) required very high torque to stop the weeping, but I could always just crank them down and get by.

It's strange because some felt looser than I would think, and others felt tighter than I would think. The strange part is that they are both brand new cars, so they were like that from the factory.