The Mustang Forum for Track & Racing Enthusiasts

Taking your Mustang to an open track/HPDE event for the first time? Do you race competitively? This forum is for you! Log in to remove most ads.

  • Welcome to the Ford Mustang forum built for owners of the Mustang GT350, BOSS 302, GT500, and all other S550, S197, SN95, Fox Body and older Mustangs set up for open track days, road racing, and/or autocross. Join our forum, interact with others, share your build, and help us strengthen this community!

Boss 302S/R owners

isrboss

I'm talking with Ford Racing about the brake fluid spitting out of the reservoir onto the paint during tracking. I was told the 302S/R's don't have the problem. Marty told me we share the same brake reservoir etc., but why am I spitting brake fluid out and you guys aren't?

Does anyone know if it is safe to trim a 80% cotton sock to wrap the brake reservoir? I don't want to melt the sock to the reservoir or ignite it.

Any help would be great!
 

ArizonaBOSS

Because racecar.
Moderator
8,551
2,389
Arizona, USA
The 302R/S use a different master cyl. and different (05-09 style) reservoir.

Typically you will have this problem if you run with "too much" brake fluid in the reservoir. We saw this on our '06 as well. I fill mine just above the "Minimum" carat on the Boss and don't have any issues.

As far as the rags are concerned, I've seen multiple pics of the 302Rs using rags zip-tied around the reservoir cap for this very reason.
 

isrboss

Thanks AZGT, I was thinking of running Teflon pipe seal tape around the reservoir a couple times and run it midway between the max-min. Is the reservoir just distorting and causing gaps in the cap?
 
38
0
Had this problem at the first track event 2 years ago. 9 new Boss's at Ford Rally event.. MMP in July, 100 degree day.
Ford development/test driver who was there, called the Boss design engineer's for us.. He recommended running the reservoir about a 1/4" or so down from the top.
Thermal expansion of the fluid as your brakes heat it caused the "brake fluid" spitting from the vent hole. Hasn't been an issue since.
 
The only time I have has this problem in my S is when I have topped off my fluid with old pads and latter put in new pads.
I changed all 4 pads and rotors once and a LOT of fluid came out on the first track session.
 

isrboss

The fix is to run the brake fluid level just above min on track then, is this correct?
EDIT:
Here is what I did, set fluid level between max and min, and found some header wrap in the toolbox. I see the 2 vents are slots that release at the base of the cap, so I made the containment dish above the base of the cap. Then I used clear electrical tape, taped the base of the wrap to the reservoir to contain the fluid. I have the min level check still visible, so I can see if level goes below the min. I have a track day at Sebring on May 25th, I will update the thread after.

20130523_153031.jpg
 
isrboss said:
The fix is to run the brake fluid level just above min on track then, is this correct?
EDIT:
Here is what I did, set fluid level between max and min, and found some header wrap in the toolbox. I see the 2 vents are slots that release at the base of the cap, so I made the containment dish above the base of the cap. Then I used clear electrical tape, taped the base of the wrap to the reservoir to contain the fluid. I have the min level check still visible, so I can see if level goes below the min. I have a track day at Sebring on May 25th, I will update the thread after.

20130523_153031.jpg

See you at Sebring Saturday, I'll be out on the big cement pad, look for an orange '12 Boss.

Doug
 
Most teams do put something like the blue shop towel that come in rolls between the cap and reservoir. The bottom line is some leak and some don't, just the way they are made possibly poor quality control. I have never had mine leak no matter how full it is.
 

Grant 302

basic and well known psychic
My suggestion is to replace the cap once you've had an overfill condition. I believe the cap's gasket is supposed to flex/contract/expand with the change in fluid volume. But once fluid gets in and around the 'button' part of the gasket, it would only take a small volume change in the reservoir fluid to make any fluid around or above the gasket puke or weep out.

Otherwise, try to keep the cap relatively dry and I think most of the issues will go away. I do not recommend trying to clean the cap as you don't want to get lint in the brake system.
 

isrboss

Update, ran the car at Sebring today, and ArizonaGT was correct. I set fluid level to between max-min, and had no fluid come out of the cap.
 

TMO Supporting Vendors

Top