[Alaskan]

All, I lost the dust cap on the front brake reservoir vent screw on my 2007 RT. With the dust cap gone, when I apply the front brakes the brake fluid comes out of the vent screw. Is this normal? I know I need to buy a new dust cap and replace the missing one, but I am unsure if the brake fluid leaking out is normal. The dust cap does not look like something that should be keeping the brake fluid in the system. The dust cap looks more like what it's name describes, simply a dust cap. Any help?

Attached is a picture of the vent screw, as I know not all models have this.

Thanks....Alaskan

 

[New2rt]

That's a brake bleeder. When performing a brake bleed you start and finish with this bleeder.
Fluid Should NOT be leaking from that bleeder. Check it to be sure it's tight but be careful it uses a light torque.

 

[gerhard]

I don't know if this normal but be careful with brake fluid and painted surfaces, brake fluid makes a great paint stripper. I think it will also mark up aluminum.

Gerhard

 

[Alaskan]

The bleeder is not loose. The fluid is coming out of the hole in the middle of it. So then I assume the bleeder is bad and I can simply replace it with a new one, correct?

Thanks for the help.

Alaskan

 

[JayJay]

The bleeder is not loose. The fluid is coming out of the hole in the middle of it. So then I assume the bleeder is bad and I can simply replace it with a new one, correct?

Thanks for the help.

Alaskan

There really isn't anything on that part to fail. Sounds to me like a piece of crud in the seat. Having said that, I'd get a new bleeder part and cover anyhow, but when replacing it I'd do a really careful wipe of the internals of where it goes in (maybe with a Q-tip?), then carefully squeeze the brake handle to flush out the hole, then reinsert the bleeder valve and tighten it down BEFORE RELEASING THE BRAKE HANDLE (or else you'll suck air into the system). Then bleed it out the new bleeder valve to be sure you get the air out. As noted above, be sure to wipe up the brake fluid immediately, a good soap/water wash of the reservoir might be a good idea too. Brake fluid, indeed, is a pretty good paint stripper.

JayJay

 

[Alaskan]

Thanks JayJay. Any chance I could pull the old one and clean it and replace it, and hopefully have it work? Not being cheap but my dealer is 50 miles away and a trip in and back will surely kill most of a day.

Thanks...Alaskan

 

[JayJay]

Thanks JayJay. Any chance I could pull the old one and clean it and replace it, and hopefully have it work? Not being cheap but my dealer is 50 miles away and a trip in and back will surely kill most of a day.

Thanks...Alaskan

Well, if you don't try you'll never know. Just be real sure to get it dry before you reinstall. Any water in that system is a big huge no-no.

I haven't pulled a bleeder valve in quite a while, but IIRC they are a shaft with a tapered end to fit into the seat. They are hollow most of the way down with holes drilled in the side of the shaft to connect with the hollow core. When they're tight the tapered part sits in its seat and holds pressure. When backed off the fluid can escape between the seat and the tapered end, thence through the holes and up the shaft. So I'd look to the quality of the seating surfaces in both the seat and on the bleeder valve.

BTW, you can always mail-order a replacement if cleaning doesn't work.

Just be careful about tightening. If the seating surfaces mate up correctly it shouldn't take much torque to seat them - snug plus a micro-skoche more. I don't remember the spec but I would guess around 6 Nm. Too much torque and you've stripped the handle, and then you will either have to put in an insert or replace the handle. And I don't imagine those are cheap.

An alternative suggestion - if you haven't changed your brake fluid in a while, this might be a good time to do it. BMW recommends every two years. If it's time and you don't do that yourself, take it in and tell the dealer to check out the leak.

JayJay

 

[Alaskan]

Thanks JayJay. I think I will pull it off and see what happens. Perhaps it is just a tad loose also. Just waiting for the wife to pull her car out so I can have more room!!

Brakes were bleed last fall right before the bike was put up for the winter, so I will skip the bleeding if possible.

I will let you know how it turns out. Is thread tape required on this connection? I am guessing not if it is a tapered fit.

Thanks again....Alaskan

 

[JayJay]

No, no thread tape. The threads will be straight, it seals on the tapered fitting on the bottom. See attached for a picture of what the bleed valve looks like. What you want to concentrate on is the tapered part at the bottom, that's where it seals.

JayJay

 

[New2rt]

Once you loosen or remove the bleeder you really should bleed the front brakes, at the very least bleed that one.

If you can't see anything wrong with the bleeder, to include grime, there is the possibility of a crack in the seat.
Rare but can happen.

 

[Alaskan]

First off, thanks for all of the help. New2RT, sorry that I did not understand what you were getting at when you asked me to see if it was tight. I did not realize that loosening it would allow the fluid to come out of the hole until I read JayJay's post. As you can see, I am not familiar with how the bleeder valve works.

The issue was that it was just a hair loose. I tightened it up (without removing it) and it passed the squeeze test in the garage. Then I took it for a road test, and it passed there also.

So, it was just a hair loose was all. Thanks for everyones help, and sorry for my ignorance. Seems pretty simple now that I understand how it works!!

Alaskan

 

[beech]

I don't remember the spec but I would guess around 6 Nm. Too much torque and you've stripped the handle, and then you will either have to put in an insert or replace the handle. And I don't imagine those are cheap.

The Factory Manual says the torque on that fitting is 2 Nm or about 1.5 ft/lbs.. Nothing to loose, Loosen it as if bleeding, pump a little fluid through it into a hose fitted to it, secure it, release the handle. No more leak great. Does it still leak..... now you have to do more. If the housing is damaged you will never seal it with a new bleed screw. If you remove it completely I think a complete bleed sequence is in order to be sure no air slipped in. (the ones down on the caliper are listed as 7 Nm for the K12s and 9 Nm for the K13s I'd go with the 7 Nm )

 

[New2rt]

First off, thanks for all of the help. New2RT, sorry that I did not understand what you were getting at when you asked me to see if it was tight. I did not realize that loosening it would allow the fluid to come out of the hole until I read JayJay's post. As you can see, I am not familiar with how the bleeder valve works.

The issue was that it was just a hair loose. I tightened it up (without removing it) and it passed the squeeze test in the garage. Then I took it for a road test, and it passed there also.

So, it was just a hair loose was all. Thanks for everyones help, and sorry for my ignorance. Seems pretty simple now that I understand how it works!!

Alaskan

Sorry about that, I assumed and well you know how it goes.

Thanks to JayJay for a proper explanation.

 

[JayJay]

All's well that ends well, and Alaskan avoided a trip to the dealer and a day off work. (Although - is a day off work and on the bike really something to be avoided?). And, you now have a new skill.

Rain yesterday in the Bay Area, sun today. Hoping to watch Venus do its thing this afternoon. Yippee!

Thanks for the lookup on the torque, Beech. It's easy to overtighten, and not necessary. Either it works or it doesn't.

JayJay