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Brake fluid reservoir

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spyderman83

Proven Member
38
2
Nov 21, 2012
Roscoe, Illinois
I am wanting to come up with a brake fluid reservoir to compliment my engine compartment. The tank for it is not going to be a problem to build but proper venting may be. On a stock system you have a diaphragm of some sort to alow air into the reservoir but not the fluid. I have been searching for a cap that would work that I can actually get a bung for. I know there is a certain person making tanks but not to my liking. Any input would be appreciated. Has anyone been down this road before?
 
No brake system allows air into the system!

Think about it! What does air contain? Water/moisture the diaphragm is there for expansion not to let air in/out and you dont need it either so you can just get any cap you want to make it work,
 
You saying it goes to the res but the res is where the fluid is! What you mean is the cap! There is no hole in the cap so it dont let air in the cap, when you put the pressure diaphragm in it traps the air inside and is just keeping it pressed down, other then that its not actually needed, most of it actually sits inside the fluid or just above so your needing to vent air etc is a worry you have that you dont need to worry about. And it has nothing to do with pad life as fluid will go down with pad wear not up or fluctuate so your over thinking it alot. As i said its not needed inside so just a normal cap of any brand will be fine! Evos dont use them as my evo res for brakes has a small cap and zero diaphragm inside just a sealing o ring.
 
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If it was not vented the system would not work properly. There needs to be air vent between the diaphragm and cap. Not every brake fluid cap has a blatant hole in the top. A stock 2g dsm cap vents through the edge of the diaphragm.(top right in picture) You can not use just any cap. Your EVO also has a diaphragm I can't tell you off hand how that particular one works. Pull your cap off and look at it.
 
Thank you 2gmitsueclipse!

....as I was saying the cap must be vented!

My friend owns a machine shop and I am having him make me a billet brake fluid reservoir. Probably doing a design similar to CNC brand o-ring at the top and bolt together. I am making my own cap and bung. That's why I'm here to get ideas for the cap diaphragm design.

This is a picture of my engine bay...I want it to look cleaner to match and I'm not happy with just the jmf cap.
 

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I heard something about a vent before and in all honesty I thought what the guy was saying was all BS. Come to find out he was right. Learn something new everyday.
 
examples off the top my head..
You put your straw in your soda, put your thumb over the top to seal it, lift the straw up and and what happens? Fluid doesn't drain well does it?
Or a gas can without a vent doesn't pour well.
 
Simply put, the diaphragm act like a liner keeping the hydraulic fluid from contacting air (contains moisture). As the pads wear, the fluid level decreases in the reservoir. To prevent a vacuum being formed in this sealed system, air fills the void in the reservoir between the cap and diaphragm. This is why you should always loosen the brake reservoir cap when replacing brake pads (pistons are pushed back in).
 
Ok if you read link that closely it basically says its not a vent! A vent is holed and this does not have a hole! The vent they are talking about is the traped air inside the diaphragm which is what i originally said it was. They did mention a hole but thats not what mitsubishi did or have ever done!

And as i said before you dont need a diaphragm! Your so anti what i say its like you want a different answer? Im telling you to buy any cap that suits your liking and thats a wrong answer to you!
 
i am working on something you guys may like. but still waiting on some new equipment first
 
Any updates? I would love something that looks like that Wilwood one.

I figured out how I'm doing my cap and I'm pretty happy with it, that's the only real news I have.
Mine will be a lil while still my friend at the machine shop has been busy and I'm not happy with the design yet. I will be sure to post pictures when it's complete. If I had to guess I'm thinking spring time.
 
Can't wait to see what you come up with. And for the record, the resivoir does need vented. You may not notice out as much in a car, but on a motorcycle, if you seal the resi, as soon as you build heat into the brakes the expansion of fluid with no hole to allow the level to fluctuate will leave you with the brakes locked up solid, been there first hand,
 
Can't wait to see what you come up with. And for the record, the resivoir does need vented. You may not notice out as much in a car, but on a motorcycle, if you seal the resi, as soon as you build heat into the brakes the expansion of fluid with no hole to allow the level to fluctuate will leave you with the brakes locked up solid, been there first hand,[/QUOTE

I have a nice cap it will use a ford style diaphragm. Just need to make up my mind on the rest of it.
 
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