spode134

On my 79 track car i am getting brake fluid spilling out of the resevoir during races. I have tried lowering the level and replacing the cap but it is still barfing fliud all over. It looks to be coming out the vent hole in the cap so I was thinking of making a vent hose to maybe a catch can. Has any other racers experienced this?

John Veninger

Thick paper towel and a rubber band.

PorKen

Power bleeder cap, and a catch can in place of the cruise control actuator?

Stan.Shaw@Excell.Net

Hmm, maybe use the power bleeder with some pressure on and it would act as an expansion tank?

John Veninger

My solution cost $0.04 and doesn't add weight

spode134

John, your solution was my solution also but I am using alot of 30$ a can fluid and paper towels.
Darrin.

SharkSkin

Are you running it at or near the minimum level? Also, is the fluid fresh? If it's old and/or you are boiling it that could account for what you're seeing.

I don't have track tires, and may not push as many G's as you, but I do toss it around pretty hard and have never seen this. I keep it at the "MAX" line.

123quattro

That is really strange. The volume in the reservoir should never increase. By venting the reservoir, you will introduce moisture, which will lower the boiling point of your fluid. Sounds like it's already boiling massively, to introduce that much air into the system, but you didn't mention a soft/long pedal. Very strange.

svp928

Sounds to me like you are boiling the fluid... I've never had fluid come out of my res at the track, even when they have been pushed to nearly catching fire...(don't ask). Try flushing the system completely with Super Blue or a similar high-temp fluid, and then concentrate on keeping your foot off the brake pedal, applying them harder for a shorter time, etc.. I know a lot of instructors try and beat into my brain that the left foot belongs on the dead pedal unless its really needed elsewhere...

GUMBALL

First, if the pedal is not getting soft, you are not boiling the fluid.

I have had that with race cars occasionally. When the fluid gets hot, it expands. That is not unusual.

You just need a larger breather than the stock cap. My solution, get about 12" of clear vinyl tubing, about 1/8" to 3/16" ID. Make a coil of it about 3" diameter (fix with tie-raps), and insert one end thru a hole drilled in reservior cap. Seal with RTV.
The coiled tube allows the fluid to expand, then contract - without spilling, and it does not allow the entry of enough moisture to affect the fluid.

spode134

Gumball, thats kind of on the same track as what I was thinking, by my figuring the vent is to allow air in to take the place of the fluid that is used up as the pads wear. I figured maybe a combination of vibration and the hard braking which would slosh the fluid forward where the filler cap just happens to be! Is the cause ?
American cars use a bladder that stretches with fluid on one side and atmosphere on the other, bikes have this too... maybe a better system. I guess the Germans don't have everthing figured out better.
I will experiment with the vent hose idea, got a race next weekend.
Darrin #134

mark kibort

your not alone. I spray brake fluid all over the driver side of the engine compartment.
dont know if its venting, g--forces, etc. but what i do know is that its brake fluid and its kind of a mess after race sessions.

MK

John Veninger

I never push out that amount of fluid. Could your MC cap be bad?

svp928

In Kiborts case, I sure its the Amsoil...
The rubber seal is definitely a good idea, but hard to implement on the 928 because of the shape and location of the reservoir. Darren's coil or small catch tank may be the only choice..

IcemanG17

Even at my DE level I notice brake fluid splashing about....not that much...but it does make a mess