How does this brake fluid look?

[stephenkirsh]

So I've never replaced brake fluid on a car, myself or paid somebody to do it, so I don't know what new fluid looks like or what bad fluid looks like.

I figure I should do new lines and fluid on the ZHP since I've no idea if/when the PO did it. Since I autox/track the car, I was gunna get some steel lines (Turner's?) and decent fluid.

So uh. How's this look? It's hard to tell in the photo. Looks pretty dark to me. The dab on the towel for reference (towel was white).

13090

13091

[SoCalZman]

I thought we were supposed to change our brake fluid every 2 years or so

[gmurphy]

I need to do mine soon too.


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[Avetiso]

It's old, but I don't think it's a big deal. Just flush it out and be on your way, along with replacing the lines if you feel compelled to do so.

[brettbimmer]

It's old, but I don't think it's a big deal. Just flush it out and be on your way, along with replacing the lines if you feel compelled to do so.

+1. Brake fluid is hygroscopic, meaning that it absorbs moisture from the air. Usually HPDE events insist that you change the fluid annually or bi-annually so as to minimize the moisture that causes a lower fluid boiling point. You can change it yourself if you keep a few basics in mind. Best to extract old fluid from reservoir first and fill it up with fresh fluid. Start the bleed from brake assembly furthest from the reservoir as this pulls the old fluid through the lines first, and you won't contaminate the others later with old fluid. So, RR, LR, RF, LF is typical bleed procedure for the ZHP. I use a vacuum bleeder with a compressor and also a helper to pump the pedal sometimes, but I am seriously thinking about a pressurized bleeder as it would make it even easier. Fluid brand of choice is probably like asking which oil everyone uses, though I have had good luck with ATE Gold 200 for many years. Same could be said for SS brake lines. I just put them on my E36 as the old lines were cracked badly, but I have to say I have not noticed any difference in pedal feel, and I am pretty particular. Also, I usually date the reservoir with a sharpie marker when I change the fluid. Simple and effective way of keep tabs of when it was last changed, and wipes off when changing it the next time. Keep the brake fluid away from vehicle paint too as they don't get along well (it can lift paint if left on the painted garage floor, etc.). Hope that this helps!

[Dave1027]

I've replaced brake fluid on vehicles because it was dark. By the next day it was dark again and I never noticed any change in brake feel. Felt like a waste of time.

[derbo]

Brake fluid is one of the most neglected fluids to change out on cars. BMW does suggest every 2 years to replace it and usually its to prevent it from being too dirty and it also makes sure there is no air in the lines. As Brett mentioned, brake fluids have a dry and wet boiling point. Dry boiling point is when the brake fluid does not have water in it. As the brake fluid absorbs moisture over time, the boiling point of the brake fluid will lower and move towards the wet boiling point number.

IE. AFE Typ 200

Dry BP: 536 degrees F
Wet BP: 388 degrees F

For normal daily driving, brake fluid should not exceed even the wet boiling point.

Dave,

If your brake system is still fine, you shouldn't feel a difference. Fluid change focuses on removing the brake moisture and containments. However, the brake fluid shouldn't have turn dark again that fast. You might have to do another flush.




Steve,

Since you do auto-x/HPDE, I would definitely suggest at a minimum, replace the fluid 1-2 times a season. The goal of the flushes is to make sure there is no air in the lines and that there is minimum moisture in the brake fluid to keep that boiling point near the dry number. I usually replace my brake fluid before every track event but that is a little excessive if you aren't boiling your brake fluid.


I use TMS check-valve bleeder bottle. It is the most inexpensive way to do a single man bleed job with minimum hassle. As Brett mentioned, Do the furthest caliper from the reservoir and work your way to the closest. (RR, LR, RF, LF).


http://www.turnermotorsport.com/p-176959-turner-motorsport-brake-bleeder-bottle-with-check-valve-simple-bleed.aspx

http://www.turnermotorsport.com/image/brakes/brakes_BBMCV_simple_1_man_brake_bleeding_bottle.jp g

[stephenkirsh]

Ok thanks for the tips guys

[Smolck]

For me keeping my fluid fresh and clean is added insurance against expensive DSC problems.

I tried to DIY a pressure bleeder (just did mine last weekend) and the spare cap I got from a junkyard wouldn't seal. In the end, I made the wifey my brake pumper. I too followed the RR, LR, RF, LF sequence. Took some time, but fluid is clear as it can be. Mine was pretty bad and it made a noticeable difference for me.

[stephenkirsh]

Expensive DSC problems? Hat does that involve. News to me.

[JupiterBMW]

FWIW, I've swapped to SS brake lines on two ZHPs now and honestly, I can't really feel much of an improvement. So, if you want to save the $125 or whatever they cost, then don't bother. A good flush and proper bleed (as stated above a few times) will be your biggest help. I too recently flushed to the ATE Type 200 fluid.

Also, this time when I flushed/bled, I hooked the car up to INPA and ran through the ABS functions to activate and ensure all of that was bled/flushed as well. Seemed to help with a nice stiff pedal...

[stephenkirsh]

FWIW, I've swapped to SS brake lines on two ZHPs now and honestly, I can't really feel much of an improvement. So, if you want to save the $125 or whatever they cost, then don't bother. A good flush and proper bleed (as stated above a few times) will be your biggest help. I too recently flushed to the ATE Type 200 fluid.

Also, this time when I flushed/bled, I hooked the car up to INPA and ran through the ABS functions to activate and ensure all of that was bled/flushed as well. Seemed to help with a nice stiff pedal...

1.) do you track/autocross?
2.) I was under the impression the rubber hoses wear out. Is that not true/over stated?
3.) do you have a suggestion on alternatives? I don't wanna cheap out on any part of the brakes, but OEM lines are about $40 each.

[BCS_ZHP]

I've replaced brake fluid on vehicles because it was dark. By the next day it was dark again and I never noticed any change in brake feel. Felt like a waste of time.

If this happens, it means your rubber brake lines are deteriorating from the inside out, their inner rubber lining is disintegrating very time you push the brakes. If you see dark after a brake flush, then you need to replace your brake lines, OEM or SS is your choice.