To the people who track your cars:

Just came back from a weekend at Mid-Ohio; all went great but I've got brake fluid coming out of the reservoir and making a mess, even though the cap is on as tight as it will go. I thought of putting a layer of celophane between the cap and reservoir--has anyone done this? Or maybe it's coming from someplace else (gulp)? Brakes were great all weekend; it's Motul 600 so I don't think it's boiling.

 

Wrap a shop rag around the cap and tie in place with safety wire or a tie-wrap. Worked on our Datsun 510 race car.
Jim

 

When was the brake fluid last bled/flushed? It sounds like it may just be a little over-filled. Check the level. If that's the problem, you can always purchase a turkey baster and remove a little.

 

I just heard of a fix last weekend at our local SCCA race. If you look on the inside of the cap you will see a groove. This allows the reservoir to vent as the fluid goes down due to brake pad wear.

The fix is to fill the groove with silicone so it can't leak under cornering forces. You will need to crack the cap once in awhile to vent it.

I plan on doing this before my next track day.

 

Good info, man! Thanks

 

My car did the same as yours when I did a couple of track days. When talking to other MINI drivers at the track I found that allmost all of the cars leaked some fluid. Didn't mater what kind of fluid. (stock or hi-temp)

What I found was that my reservoir was overfull, not a lot, but overfull. It seems that most of the cars were overfull, not by much, but to me in my opinion, overfull.

The dealer did a 2 year service on the car and again it's overfull. It seems to me that it is a little too easy to overfill. I have since used the old tried and true "turkey baster" with good results.

If your are concerned about contaminating the fluid or changing the level, the rag and zip-tie worked for me as well.

Hope this helps...

 

Thanks for the replies--the fluid level is about halfway between MIN and MAX so I don't think it's overfull--I'll prolly do the rag thing too. My 325 does the same thing but my old 318 never did--go figure.

 

I had a conversation a while ago to one of the guys here in Australia who tracks his car a fair bit. I had noticed that paint was flaking off the break booster. I think if I remember correctly he said that it was due to the reservoir overflowing because the ABS system apparently returns fluid back to the reservoir at fairly high speed and as a consequence, it splashes on the lid and during cornering leaks out. Could be wrong but sort of makes sense

 

A car without at least one zip tie won't pass tech, will it?

 

How can you get a turkey baster into the master cyl reservor? Mine has a plastic screen and I can't get it to come out. Tried needle nose pliers.

 

brake fluid strips paint, fyi.

 

I just did a track day this past weekend and the brakes worked perfectly as well. I just noticed the same leak that you guys that track your cars. It looks like it is splashing from te top of the reservoir tank and leaking down to the my garage floor. My reservoir tank looks to be at the MAX level. Does this mean I have too much fluid? I have Super Blue Fluid.

Can you guys explain the rag and zip tie method?

Arly

 

Funny how these things happen.

Never had this problem before, but after my fifth track day this year, there it was. Noticed it when I was changing back to street tires and saw the fluid dripping down through the wheel well under the master cylinder. Checked under the hood and there it was, a bunch of escaped fluid down under the master cylinder.

Waited till I got hove and sprayed it all down with brake cleaner and then hosed it out.

Scarry, as I know how damaging this stuff is to paint and metal. The rag and zip ties sound like it might be a standard setup from now on.

 

Just had a track day yesterday, and had the same problem too. I didn't even notice it until one of the officers of our local MINI club came up to see if mine was leaking, as his was.

I thought the two piece reservior might be leaking, but the vented cap thing sounds more the reason.

He had already used the zip tie method, so, for the rest of the day, a folded paper towl with my fiance's sacrificed doubled-up hair scrunchie did the duty of leak moppage.

So, how can we prevent it, rather than deal with the problem? Do they sell an aftermarket reservoir cap you can interchange for track days?

Brake fluid is nasty stuff.

 

I think emini nailed it when he said to take a little fluid out....I did so on my 325 and I haven't lost a drop since. I have the fluid level about 2/3 between the min and max marks (1/3 down from max). When my new Cooper arrives in a few weeks I'll try that.

 

My car's have always done that with track work... those include 2 bmw's and a 2004 and now 2005 mini.... I think it is normal, as pressure goes up out of the cap as well as down to each caliper...

I usually pop the hood post each session, and clean off the brake fluid resevior... I think I will use a clean cloth with a zip tie in the future....

 

This is a common problem with many cars. The "normal" fliud level is much higher than you would think. Under high corner loads, the fluid does splash up on the cap and can run out. I am not aware of the abs causing this problem as if you introduce brake fluid into the m/c too fast it can become aereated and we all know that would be bad. The best option that I have seen is mentioned above. Use a shop rag on the top of the cap. I am an inspector for SCCA as well as CSCCA and have seen this on may other cars. I have built many race cars of several varieties and have the same issue be it with Willwood or other high performance manufacturers. The only other option is to plumb a fittin in the top of the m/c cap and remote a line with a filter on the end to a higher location as to allow venting as well as a place for the fluid to travel to.