Brake fluid leak from caliper
 

I was at the track the other day. The ambient temp was close to 90F track was at 125-130F (measured).

The car ran fine, no breaking issues anywhere on the track. Once I parked my car and went around to check tire pressures I noticed that I had break fluid leak from the bleeder nut on the caliper. By the time I checked it, it was already all white and sticky (we made a few dirty jokes lol). But on a serious note, nobody knew why this has happened and if it could be some kind of problem!

I did two full days of track days in similar but not as hot temps the weekend before and this has not happened.

http://uploads.tapatalk-cdn.com/2016...b8eee1e9f7.jpg




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Almost looks like there was some sort of sealant on the bleed valve (like a Teflon product) that got so hot it melted off of the valve threads. Never saw brake fluid that color (unless it turned to foam). What brake fluid are you using?

You might be right. I use RBF 600. I bled the brakes before myself and never applied any Teflon, etc. though. It's possible someone did it before me?

I just thought maybe the fluid boiled or something and then changed color. I'm quite confused what that was.


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Even if the fluid had boiled it should not leak out like that. I think it must have been some Teflon thread sealer leaked out from the threads area. The fluid is sealed from a tapered seat, the threads have nothing to do with sealing the fluid. Sometimes people put a teflon sealer on the threads so when vacuum bleeding you can get a better idea of when all the air is out, without it you can suck air in around the threads and back out the bleeder port, it won't enter the caliper it just makes it hard to judge when all the air is out of the system.

I say clean it off and see how the pedal feels. The fluid your using should be sufficient for track use I would think.

Man - you have been beating on the brakes that hard that the caliper sh1t itself ............

That is normal in high temps for our stock calipers to poop out the bleed valves. It is because of the heat. Whatever pads you are using sure coaked up the rotors. This is why folks install air ducks and/or upgrade to BBK kits for track duty.

My calipers will do that to during a trackday. The calipers get hot and expand around where the bleeder valve is. Allowing some brake fluid out. There is another thread on this. This something that our stock 'bono's will do. The rears more then the fronts. Far as I know. There is no way to get the stain off the caliper either. :shakes head:

Yup, has happened to mine as well during a track day. Not every time though. Even with cooling ducts and RBF fluid.

yeah, the caliper expands when it gets real hot and fluid seeps out around the threads of the bleeders.

Sorry with the delay of my reply.

Okay sounds like a consensus of calipers expanding around the bleeder valve.

I flushed my brake fluid and it was just fine, didn't cook or burn. Color was almost identical to brand new fluid.

As a side note, my clutch fluid was black...and this is only after 6k miles and 5 track days. Not sure what causes this. Clutch always behaves perfect, synchrorev is a pretty crappy at matching revs on the other hand.

Also, whatever it was that leaked out was super easy to clean off. It was not like you described.


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Well enough people are saying this so it must be happening but it really does not make sense because the threads are not what seals the brake fluid in the braking system. If it were like a pipe thread then this would add up as the heat would cause the caliper to expand and then the tapered seal of the threads would loosen up and allow seepage. But the seal on a bleeder to caliper is a tapered seat so unless the seat is getting distorted which would be incredibly hard to do then even if the thread fit got looser the bleeder would have to physically back out for it to leak. Just doesn't add up.

I had the same issue in Monza

http://www.psm1999.net/images/share/...14_092050a.jpg

with sport package Akebono, Project Mu Pads, RBF600 and stainless tubes....

I know what you're saying. The caliper gets hot enough to distort around the seat. Allowing some fluid past. If you look at the pictures. The heat is traveling from the pistons, straight up to the bleeder area. If the bleeder area was about 1/4" higher or had more meat to the outside of it. We might not be talking about this.

Huh, I guess. Just what a weird issue, never seen that one. Looking at the pick holy crap hot spots all over that rotor lol, must have been pushing it.

I thought those were from the abs kicking in on the rear tires possibly, didn't have those on the front.


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This exact same bleeder nipple leak thing happened to me on the track to.

Is this consistent on both calipers or just one?

Same happen to my Z... in the rear left caliper last time I track the car. But was just a little :tup:

Depends on the track and your driving style. You could go from none leaking, to all of the nipples leaking.

Also happened on my 2014...running XP8's. Front two calipers at the same rate. I checked tightness between runs...in which both were extremely tight. Not sure if there is a torque spec for this nipples or not.

The torque spec on bleeder screws are usually in the range of 8 ft/lb's. And to further provide evidence of this, my front caliper's have done the same thing as your's. It's from the cheap caliper design expanding under high heat levels. However, i've not seen the rear calipers suffer from this issue. Did you have VDC turned off during the track day?

I've had all 4 calipers leak at one time or another. And yes, I track with the VDC off.

Same here VDC off all the time when i track my car

Interesting. I guess I just don't use the brakes that much on the dragon to get the rears hot enough.

Edit: To expand on this before any questions, I have only had the fronts do this twice. After the second time, I drilled not using the brakes as much into my brain again, as I had forgotten that when I went from my old eclipse with Brembo's to the Z.

VDC is always turned off for track day! :)


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That's good. One thing you can do to help expel heat from the calipers is to use two piece rotors, and titanium pad shims. You can find a few two piece rotors for the fronts, but the rears are from Z1 only. the Ti pad shims can be found at Hard Brakes.

https://hardbrakes.com/index.php?mai...roducts_id=106

Turning off VDC does not turn off ABLS, which is responsible for applying the brakes to the rear wheels when it detects wheel slip. Since you're only experiencing this on the rear brakes, I would guess ABLS is the culprit. I think you have to remove the Stop Lamp fuse to turn it off.

I have the RC brake ducts, the Hard Brakes Ti pad shims, Racing Brake 2 piece rotors front and REAR. :D

^offset by the extra brake heat due to the grip from the ginormous big booty trudy tires :driving:

:rofl2:

What is ABLS? I know what ABS is, but not ABLS?


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I believe ABLS is part of the ABS (hence the reason you have to remove the Stop Lamp to turn it off completely).

ABLS stands for Active Brake Limited Slip. It is a feature that pulsates the rear brakes when wheel slip is detected.

I had this happen at Shenandoah.

If the bleeder screw was overtightened, is that essentially gouging/damaging the aluminum caliper and therefore, you cannot simply replace the bleeder screw, but to replace the whole caliper?

If you're lucky a good machine shop could insert a heli-coil into it. I had that done and it worked. But if that fails, then yes, new caliper for you.

I must be getting quicker and braking later as my last track event I too had a little seepage and I can guarantee you mine are not overtightened. I think it is as earlier poster said the seat is just a bit too close to the piston so under high temp it distorts a little and weeps.

I never felt a loss of braking action and only did it after some hard 20 min sessions and smoking brakes but I'm not really worried about it.

I told the dealer and they said that I had bled the brakes wrong. Couldn't have POSSIBLY been the caliper fault.

Any easy way to tell this is happening is when you have a dead pedal until you push fluid back into the caliper. Once you get full pressure back, everything is fine. I've not had this happen to me in quite a while, but I also have taught myself to be better at braking.