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Brake fluid

Discussion in 'E39 (1997-2003)' started by Touring525i4dawgs, Dec 20, 2017.

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    Touring525i4dawgs '02 525it M sport

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    Does brake fluid have a shelf life if not opened? I have a can of Ate TYP 200. Wondering if I should get rid of it and go with a DOT 5.1 fluid?
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    MGarrison

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    This article mentions 2-5 yrs for unopened -

    http://www.onallcylinders.com/2014/07/18/ask-away-jeff-smith-shelf-life-brake-fluid/

    I was confusing 5.1 with silicone DOT 5; I guess 5.1 just denotes a higher boiling point, so unless you need that, there's no difference for switching to 5.1. As for switching to DOT 5 & its moisture absorption considerations, wiki mentions being incompatible with ABS systems, so I'd have to guess not recommended for BMW's with ABS. Never mind that DOT 5 & others shouldn't be mixed, so I would have said it isn't worth the bother just from the hassle of trying to clear the brake system of all the DOT 4 fluid.

    https://en.wikipedia.org/wiki/DOT_5
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    charlson89

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    Ditto on mentioned above just stick with DOT 4. I believe Mgarrison is correct 5.1 is silicone based fluid and will not work in your braking system.
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    Touring525i4dawgs '02 525it M sport

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    As always great info. Do you think the un opened Ate will still be good?
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    Touring525i4dawgs '02 525it M sport

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    Missed first part of your answer. Guess this can has to go!
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    MGarrison

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    Brake fluid's cheap compared to the cost of brake system components - don't feel bad about pitching it if you think it's old enough to be suspect. I have an indie shop nearby that collects brake fluid, coolant, & oil & let me dispose of mine, maybe you'd have one nearby that does also.
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    Touring525i4dawgs '02 525it M sport

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    Yes my mechanic will take it. Kind of bummed but the small print for the brake lines I want are not made for my wagon. Have any suggestions?
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    charlson89

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    Touring525i4dawgs '02 525it M sport

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    Thanks for the link. Going to do the brake lines at the next National Capital Chapter DIY.
    MGarrison likes this.
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    Touring525i4dawgs '02 525it M sport

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    As I am getting ready to replace the brake lines to steel my Bentley manual says I will need a DIS-plus/GT1/MoDoC Service tester. Is something I need to buy or will the shop I am doing the DIY at have it?
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    MGarrison

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    I have no idea, maybe Charlson will know - maybe for cycling the abs unit? I'd think that wouldn't be necessary as long as you don't let the hard lines just empty out. Apparently on E92's (& presumably BMW's of that vintage to now, maybe even earlier) the brake system has a relatively simple means of 'locking' (for lack of the exact or better term) the brakes so brake fluid won't drain if you're doing something like swapping the flexible lines. Bentley manual said something about pumping the brake pedal twice fast or something like that, not remembering off the top of my head. I have no idea if that's something implemented in E46's or not, although I wouldn't be surprised if not. If the E46 is anything at all like my later E92, the problem is access to the first soft lines coming off where the hard lines that run to the rear of the car terminate. I'd expect the E46 is different - the E92, with the wheel off, you can look right AT them and think, hey! easy peasy, they're right there! Uh, yeah - the access and angles for getting a wrench on and turning... uh, yeah, not so much. If you can't get the brake line nuts free from the brake lines quickly enough, you have brake fluid leaking out the entire time until you can free the line and then cap the end of the hard line, and if it's a pita, it can take so long the fluid will drain from the whole line - ugh.

    I didn't know about this tool until earlier this year, but, on the presumption it would work, it sure would've been handy in the past installing ss-lines on the rear, a swivel-head ratcheting brake-line flare-nut wrench. If it works, brilliant (I bought one, looks like a nice tool, but have had no occasion to try it yet) -

    https://www.ebay.com/itm/Sealey-Fla...090527&hash=item4d38624e76:g:-BsAAOSwFnFV--Y6

    Anyway, point being, if you can work quickly enough to separate the lines & cap the hard lines so you don't end up draining the reservoir & getting air through the master cylinder & then ABS block, presumably all you'd need to do then is just a pretty serious bleed until the air through the new soft ss lines is purged. Or, you could just someone pour brake fluid in consistently while working on the brakes... that would make a big mess! ;)
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    Touring525i4dawgs '02 525it M sport

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    Just going from the warnings in the Bentley manual.
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    charlson89

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    If you completely drain the system then yes it will be. But if you keep fluid in the revisor while replacing them you can just bleed the brakes and then drive the vehicle in a safe space and do a couple abs stops then bleed the brakes again.

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