When is a vendor going to make a fix for the brake res. leak issue?

Someone in another thread posted that they did it using an exacto knife. Perhaps he/she could post a how-to?

Ok

Yes I am the one who posted about this. What I did was wadded a small bit of paper towel and put it just inside the neck of the master cylinder to keep any particles of plastic out of it. Then all I did was carefully scrape towards me around the top of the neck where it meets up with the cap, the edge of the blade is straight down on the exacto knife so you just barley remove any plastic.

I found on mine that in between the three flat places on the top of the master cylinder neck the plastic was un even and kind of edgy. Once I took the edge off, I put the cap on and it never leaked again.

Good luck. Warlok

WOW Warlok !!

Good advice !

I am STILL waiting for Shelby to come out with a billet cap for the master cylinder

Warlok: Are you saying that the gasket mating surface of the reservoir itself is uneven, which causes a poor seal, like the surface is bumpy and just slight scraping is required?

I wrapped the neck with teflon tape, so I do not want to take the cap off to look. My other Fords (00-up) have the same problem, but it is nowhere as bad as the Stang. I may have to check the reservoirs on the other Fords!

That is exactly the problem. The top surface of the filler neck, where it mates with the cap gasket, is poorly molded in a lot of the reservoirs. I was going to smooth off the surface myself, but I chickened out. I finally did get my dealer to replace the reservoir under warranty. The new one hasn't shown any leaking in about 7 months now.

Yes

metroplex said:

Warlok: Are you saying that the gasket mating surface of the reservoir itself is uneven, which causes a poor seal, like the surface is bumpy and just slight scraping is required?

I wrapped the neck with teflon tape, so I do not want to take the cap off to look. My other Fords (00-up) have the same problem, but it is nowhere as bad as the Stang. I may have to check the reservoirs on the other Fords!

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Yes sir Northwest GT pretty much said it all. It is just a small amount of scraping needed,at least on mine. I have seen others that were knife edged on top and un even. Very poor molding process I suppose. As long as your not leaking I would leave it alone.

If this is the worst I have to deal with, I can handle it all day and still love my Stang.

My Stang leaked like a sieve as soon as it came off the truck direct from Flat Rock (we're only about 20-30 minutes away). Thanks for the tip. I will definitely take a closer look. I was afraid that a lot of cutting had to be done from an uneven sealing surface because I thought it wasn't a true surface. Now that I hear it is just irregularities and defects in the molding, it doesn't sound TOO bad

Just go buy the rubber piece from home depot. .99 cents. Done. No need for more complaining.

official_style said:

Just go buy the rubber piece from home depot. .99 cents. Done. No need for more complaining.

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Is that rubber material compatible with glycol based brake fluid?

metroplex said:

Is that rubber material compatible with glycol based brake fluid?

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Does not matter if it is or not, it goes under the rubber piece that is in the cap from the factory

official_style said:

Does not matter if it is or not, it goes under the rubber piece that is in the cap from the factory

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The factory cap is not a 100% seal. There is a slit cut into the gasket that allows the pressure inside the reservoir to equalize. There's going to be some brake fluid residue that seeps up into the back of the cap. If the gasket is not compatible with glycol based brake fluid, it could break-down and contaminate your brake fluid and even cause brake failure. From what others have said, the fact that a new reservoir can solve the leak and how smoothing the neck can fix the problem, it's logical to infer that the problem lies with the reservoir neck and not the cap or cap gasket.

Update: I took a careful look at my reservoir. Previously, I wrapped the neck with teflon tape and it did not melt. However, the teflon tape was soaked with brake fluid.

I looked at the seal surface of the reservoir and cannot see how it is malformed or a "defect". The ridge appears to be part of the molding or design. A soft gasket is designed to form itself to minor irregularities, and this ridge is just designed to further improve the sealing.

I think there are several things in common with the various fixes:

Using a rag stuffed in the reservoir to prevent plastic chips from falling in while smoothing out the neck. This may soak up or absorb some of the brake fluid in the reservoir.

Having the dealer swap reservoirs several times until one no longer leaked. It's possible the fill level was different, with the most recent reservoir not filled as much as the others resulting in the leak being fixed.

Lastly, the obvious solution is to remove some of the brake fluid from the reservoir.

There's a slit cut in the center of the gasket, and if the fill level is too high, some of the brake fluid can shoot right through this slit, onto the back of the gasket, and drains out through the cap. That's my theory at least.

A fix would be a revised cap gasket with a smaller slit, or the center piece located MUCH higher to prevent sloshing brake fluid from seeping through the slit.