Doing all around brake job on e46 w new hoses. Brake fluid!?

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Hi all, I'm doing an all around brake job in my e46 on the WE, w new brake hoses and a complete flush of the old fluid. I have two questions if you don't mind. 1) How much brake fluid should I have on hand for that? I don't think I ordered enough. I went with 2 L of the ATE DOT4 SL.6 2) Since I don't think two L are enough now, what DOT4 that I can find at the store here can I mix with (No time to order more of the same SL.6)? Would it be okay if I got 2 more L as backup from NAPA https://www.napaonline.com/en/p/BFR40012 ? Or Carquest? : https://shop.advanceautoparts.com/p/wearever-dot-4-brake-fluid-1-quart-w20017/10893760-P?navigationPath=L1*14924%7CL2*15037%7CL3*16113%7CL4*-49996987 I am aware it would dilute the low viscosity properties. Would that be acceptable? I'm on the OR coast, so not getting cold (maybe 35-38 F in winter) Cheers
 
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Jan 2, 2004
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SL6 will mix with other DOT4s, you will lose out on the thinner viscosity but you'll be fine with your E46. 2L should be fine for replacing brake lines, a typical flush will use a little less than 1L unless you have a brake bomb to flush out.
 
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In my limited experience you have plenty. I did a flush on three cars with two liters, also using ATE Dot 4. None of them involved new hoses, but that shouldn't make a significant difference. Good luck.
 
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It is all about boiling temp vs Hydrophilia or what ever you call water attractive. DOT3 boils at a lower temp. DOT4 absorbs water more readily, that is where the 2 yr life comes from. I used 2liters when I replaced everything in the Rat. I didn't want to get air into the ABS
 
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That should be plenty. Are they setup so you can swap the lines fairly quickly? I got some fluid stopper plugs on Amazon for when I have to disconnect fluid lines.
 
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Two liters should be plenty. I don't own the car you are working on. The last three cars I have done did not use over 32 ounces. 1990 Volvo 240 used the most because it has two lines per wheel, and it only used right at 32 ounces.
 
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Originally Posted by andyd
It is all about boiling temp vs Hydrophilia or what ever you call water attractive. DOT3 boils at a lower temp. DOT4 absorbs water more readily, that is where the 2 yr life comes from. I used 2liters when I replaced everything in the Rat. I didn't want to get air into the ABS
The word you're looking for is hygroscopic, but not really, most manufacturers do not put remotely close to a 2 year interval for fluid replacement into maintenance schedules. Some don't schedule it at all. It does not have a 2 year lifespan. If you find your brake performance degrades that much in 2 years, your system is either defective or you're doing something wrong like using old fluid opened long ago or keep taking the cap off the reservoir to check it an excessive # of times. The only people who need fluid changes more often are those in extreme driving conditions. Racing, long downhill/towing, etc. where they notice brake fade but are too cheap to upgrade their braking system to deal with the heat rather than the band-aid of thinking heat magically isn't produced if fluid is newer. That is irresponsible. No one should be operating a vehicle with the braking system getting that hot and continuing to operate it in the same conditions. Upgrade the braking system before bothering with 2 year replacement intervals. If 2 year intervals were needed, all manufacturers would spec this. The majority don't. There would be over a billion vehicles recalled if that was needed since it isn't spec'd.
 
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Every modern DOT 4 specced car that I have owned has recommended a first brake fluid change at 3 years, then every 2 years.
 
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I have an E46 and an E90. I bleed/flush the brakes on those cars every year (and my other cars too). Are you replacing lines only, or are you replacing/rebuilding the master cylinder and calipers? If just the lines two liters should be enough. Scott
 
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