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

Status
Not open for further replies.
Joined
Feb 9, 2019
Messages
12
Location
Us, or
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
 
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.
 
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.
 
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
 
Last edited:
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.
 
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.
 
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.
 
Last edited:
Every modern DOT 4 specced car that I have owned has recommended a first brake fluid change at 3 years, then every 2 years.
 
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
 
That is the only reason to change brake fluid because it absorbs water ,reduces boiling point, etc
grin2.gif
 
Status
Not open for further replies.
Back
Top