^ I think all of the oil brake fluid is out- it took me two 32oz bottles to make the fluid in the muster cylinder and the fluid coming out of the caliper bleeders look the same as in the bottle

 

230k miles 07 tl and I have never changed my brake fluid. Just added a little over the years if it was below max. color has always remained a light yellow....these are closed systems and rarely ever get contaminated.....if your fluid is getting real dark fast, then there is something seriously wrong with it.

 

Even being a closed system and never being opened, they still get contaminated with water. There's no circulation so unless there's a ton of heat and contamination the master will stay relatively clear. The fluid absorbs water but the worst will still be in the low spots like the calipers which are the worst place to have water since it lowers the boiling point. Eventually it equals the boiling point of water and I'm not going to drive anything that boils at a mere 212F. There is no warning when it boils. One second the brakes feel fine, the next the pedal goes to the floor and you have nothing.

 

^ I agree that it's important to bleed out the brakes on a regular interval. Just want to say that you would need 100% water in the lines for things to go bad at 212F. A good Dot-4 fluid should go to 475+ F so a little water in the lines won't cut performance that bad.

On a side note, it is comforting to hear that people are going 10 years on original fluid. That won't be me but it's nice to know you could. For example, I just changed the front pads of my car and did not bleed the rear brakes this go around. I'll bleed that rears after changing the rear pads.

 

REQUIREMENTS:......DOT 2 ..DOT 3 ..DOT 4 ..DOT 5 ..DOT 5.1 ..(minimums)
Dry Boiling point ...374 ....401 ....446 ....500 ......500 ..(F)
Wet boiling point .....x ....284 ....311 ....356 ......356 ..(F)
cSt @ -40C (max) ......x ..1,500 ..1,800 ....900 ......900
cSt @ 100C (min) ......x ....1.5 ....1.5 ....1.5 ......1.5

I cannot provide any *scientific* link or documentation for the following, but have read similar statements more than once:
DOT 4 fluid, which has a higher minimum boiling temperature requirement (446 degrees F dry and 311 degrees wet) soaks up moisture at a slower rate but suffers an even sharper drop in boiling temperature as moisture accumulates. Three percent water will lower the boiling point as much as 50%!

As for DOT-3, it can approach the boiling point of water after only 3-years. You have not taken account of the chemistry of brake fluid, and the effect of water on that chemistry. A significant percentage of water is *not* required to approach the boiling point of water.
---eof

 

I fully agree. I typed up a post yesterday regarding this but I must not have submitted it. As you said, it doesn't take much water to bring the boiling point close to that of water. I looked for that same chart and couldn't find it.

I've run straight water in the brakes and auto transmission before on a car that had to be driven home and then to the junkyard. It shifted great if not a little firm and the brakes felt normal. I put about 20 miles on that car in that condition. Any fluid that's about the same visocosity that's semi incompressible will have about the same feel. Water, antifreeze, a thin oil, brake fluid, vegetable oil, etc. Water works great and feels normal. There are obvioius long term problems that will result and the boiling point is obviously low but the driver would not be able to tell the difference unless he heated the brakes up enough to boil the water.

The main point being any brake fluid can go 10 years and the brakes will feel fine. The surprise will come the first time you have to use the brakes hard repeatedly. Unlike pad fade, boiling brake fluid gives no warning and you lose the brakes instantly.

I mountain bike a lot and Shimano brakes use mineral oil while most others use a DOT fluid. Shimano mineral oil boils at almost 600F. Some people who can't afford the $20 for a lifetime supply of this fluid go with drugstore mineral oil instead. This oil is much thinner with a boiling point about the same as water. They make claims all the time that Shimano fluid is not needed because they've had no problems with the drugstore mineral oil. I'm 240lbs and even with 4 piston ceramic piston calipers, heat sinked pads, and 8" stainless/aluminum/stainless sandwich rotors, I can get my fluid past the boiling point of water on the downhill runs. Most mountain bikers seem to be in the 150lb to 170lb range so they tend to get away with cheap fluid. The big downside is they've removed a huge safety margin by doing so and heavier people like me would have total brake failure if we used store bought mineral oil.

That's what you're doing by not changing the fluid. You're reducing the headroom or safety margin and bringing normal operating temp and maximum allowed operating temp closer together and the worst part is, there's no warning before brake failure.

I'm not trying to use scare tactics because most people will never see a difference changing once a year or once every 3-5 years but take it outside of the normal operating range and you might be in for a surprise.

 

You can find that chart here, in an article that also lists the recommended brake fluid replacement intervals for most brand vehicles. Its interesting that GM still does NOT recommend periodic brake fluid replacement, except when brake work is performed.

I did not mention it in my previous post, but the main reason for periodic brake fluid replacement is to prevent corrosion of the ABS parts. These parts are very expensive, and somewhat difficult to replace.

http://www.aa1car.com/library/bfluid.htm

 

IHC.. since when did you get a '14 328i

 

I know, I own a chick car. I THOUGHT I got one anyway. Apparently my fiancee got one lol. That's why it's hiding away in my sig. We spent 6 hours down there, I had a 335 with every option picked out including a lot of "M" options like the rims. She thought it had too much power and didn't like it. I picked out a plain jane 535, she thought the 5 was too big. We got the 328 almost fully loaded. It's turned into a really nice car so far. I raced a Hemi Challenger the other day and put a solid 2-3 cars on him. With the start stop enabled it gets 23mpg in town. Without it gets about what the TL gets, 13-14mpg. Just knocked down 39mpg freeway and that wasn't driving it easy. Probably going to get a mild tune, and I probably won't tell the fiancee. This model is definitely underrated in power. I didn't really care much but after beating the Hemi I went searching for whp numbers and found they put the full rated 240hp to the wheels. It looks like I can get close to 300whp and a lot more torque with just a tune which is fine by me since this is just a point a to point b car.

I'm sort of glad I listened to her, especially since I'm probably not going to drive it much. I'll buy the one I want in another couple years. The TL still looks nice sitting next to it but the BMW drives so much nicer with so much more low end torque and it doesn't just give up and die in hot weather. In 2 more years I'll have 60k available to spend and I'll also be knocking on 40's door just like the TL was the end of my 20s crisis, the next car will probably be a very poor choice. As long as I don't fit the typical fat, bald, white guy driving a Vette I don't care lol.

 

Shit.. I'm getting a hellcat.

The new 328i is a sleeper. Those 2.0T's are becoming the standard. You're right, I'm sure there's going to be an aftermarket box to put a couple buses on that hemi. I'm just surprised you fit in it.. I imagine it's something like this.. Bubba.

 

Sorry for any confusion- I just looked at the back of my brake fluid container to get the 475F figure. Like I said earlier, I think it's a great idea to change out the fluid so it won't be me skipping this maintenance.

Where does the water come from if you keep your reservoir full and the brakes have been properly bleed? It seems like either the fluid would need to break down and be water based or you would need a boat load of condensation from air in the system.

 

446 is the MINIMUM for DOT-4, so you may have a brand with a higher boiling point. I just wanted to point out to other readers that 475 is not typical.

No, as indicated only around 3% water is enough to cause problems. As for how it enters the system, it migrates through the rubber brake lines. There are also rubber lines from the master cylinder on some cars (like my own RDX).

GM has stated it uses special brake line covers (special type of rubber), to help limit ingress of moisture. How quickly moisture builds up in the system, will depend upon the humidity level where you live, and how much rain/ snow there is over a year's time.

Also, while some master cylinders are completely sealed, most are not. There is a built in breather, which does allow some small amount of air & moisture to enter the system. I really don't know about your TL. Some master cylinders are completely sealed by the rubber gasket on the cap, and the seal is accordianed so that as the fluid level drops, due to brake pad wear, the gasket can also drop (expand), without "pulling a vacuum" inside the master cylinder reservoir.

Clearly you don't believe that significant moisture enters the brake system - and clearly it does. There are methods to measure the amount of moisture. And there are plently of manuf references to the problem, note the GM attempt at special brake lines. There is also a reason why every car manuf except GM recommends periodic brake fluid flushes.

Again, you seem to be disreguarding the special chemistry of brake fluid - it ATTRACTS moisture, literally pulling it out of the air. That is the definition of *hydroscopic*.

 

missed this..

I'm not sure you'd own a 'vette if it was given to you.

 

Actually the ABS pump sits high, and no other ABS parts contact brake fluid, but the water will seek lowest levels and attack the caliper piston(s)/bore(s) and over time will cause the caliper to hang up.

Brake fluid is hygroscopic, meaning that it absorbs moisture. Nothing much one can do about the condition other than have fluid replenished.

 

Does not matter where the ABS pump/modulator sits it affected by moisture in the brake fluid. I had problems with my 1G Legend ABS modulator which sits up very high. Since the release valves are closed most of the time that traps the water. One thing the newer Honda/Acura's do is do a quick ABS valve self-test when the car starts up that exercises the valves which I believe makes them last longer.

Oh and there is no special tools needed to change the brake fluid in the modern Honda/Acura ABS systems, they use the common master cylinder brake fluid reservoir.

Bottom line, change your brake fluid every 3 years. I recommend Castrol LMA.

 

If you actually had the pump deteriorate because of contaminated fluid, then I stand corrected, but I've never had or worked on a pump that went bad because of contaminated fluid, but they have leaked as the "o" rings deteriorate with time/heat and some will overrun.

We do agree, change fluid every 3 years.

 

Sorry, that proves nothing...

 

I can no longer find this in Utah - used to buy at NAPA or any local store. Castrol has changed the name, and even the local (to me) distributor for Castrol (BP) does not import it. Where do you purchase it? I guess I could buy it online.

 

Sub'd in order to remind me to do this ASAP!!!