[Bestodabest]

Originally Posted by chaungo

I'm not, but I am a CF-18 technician, and I have friends who are vehicle techs on base that can confirm what you're saying is complete BS. Fluids are important to change after a certain time.




Oh great, then someone needs to get a requalification.

My friend was driving normally and was going downhill when it happened. He is far from a boy racer.

I learn very quickly about stuff on my car, and in mechanics in general in a year. I did not say I was an expert, but I know enough to know that fluid changes are important.

If you don't want to do your fluids then by all means be that guy that will cause accidents. But do not encourage other people by providing false information.

Chocking wheels once on OJT at Coldlake doesn't make you a "CF18 Technician".

That "certain time" isn't 2 years.

Your friend needs to learn what a downshift is.

The only thing you've learned in a year is how quickly banks will lend money to soldiers that sign lifetime contracts.

[Bestodabest]

I don't care.

You don't need to flush your brake fluid every 2 years. Buy the test strips to confirm.

/Thread.

[spitpilot]

Let's get focused back on technical issues rather than "gut feel"....
Here's an excerpt from a technical article about brake fluid, meassuring wet and dry boiling points etc that covers the topic well IMO...

4.0 When to Change Brake Fluid?
Many motor vehicle manufacturers recommend
checking brake fluid every 12 months, or changing
fluid every 24 months. The amount of moisture that
brake fluid absorbs depends on a number of factors
including the type of fluid, humidity, type of
brake hoses, condition of the seals and mileage.
Brake fluid will absorb 1% or more moisture per year
of service life. A two year old vehicle will have 2 to
3% water in the brake fluid. 3% water reduces the
boiling point of DOT 3 brake fluid by approximately
175°F (97°C). 3% water in DOT 4 brake fluid reduces
the boiling point by 162°F (90°C). (See Chart
next page)
Generally, the type of driving should influence when
to change brake fluid. If the vehicle is used for
towing, is driven in mountainous regions, or has an
ABS system it would be best to change the fluid
sooner. All vehicles should have the brake fluid
changed when the water exceeds the minimum wet
boil point. Motor vehicle manufacturers may recommend
brake fluid changes at lower water content/
higher boiling point than shown on the chart. OEM
service recommendations should be followed.

BMW reccomends 3 years for first flush and 2 year intervals there after...same as Audi/Vw...both use Bosch braking components (ABS valve blocks.) so I'd bet that Bosch has given some input to the car makers here about how to keep their components in top operating shape...Interesting to note both makes switched to requiring only DOT 4 LV (low viscosity) fluid at about the same time a few years back....so I'd guess Bosch drove that change as well....

[Polo08816]

Originally Posted by chaungo

Guess what, that's about over a year ago.

Guess who learned how to do more stuff within the year? And also saw more things? why do you think I'm defending my position on the brake fluid?

I've seen accidents happen because the brake fluid was so overdue, it boiled. One of my friend who hasn't swapped his brake fluid in 6 years was the vicitim of that, he had a e92 335i.



You don't have to do it yourself, I implied that if you know or don't know how to do it, just bring it to someone who does, or do it yourself.

Have you ever since a military vehicle checklist before you sign one out? Brake fluid is on the list and they tell you what is acceptable and what isn't.

My trade experience goes from normal DND vehicles to CF18s (no I'm not joking. Check out BMWTN and you'll know who I am) and guess what, the brakes on the CF18 are hydraulically operated, they swap the fluid every x amount of flights or depending if the filter has been triggered or not.

I'm not here to cause a argument, I'm just providing my own advice on maintaining the vehicle, I don't want people to start taking stupid advice of "neglecting" fluids. I don't want my family or friends to get into an accident because some idiot decided not to swap his brake fluid in 6 years because someone said it's useless to do so. The fact is if you leave your brake fluid alone and don't touch it, it will lose it's temperature of where it's supposed to boil, and it can cause an accident due to it overheating faster.

Don't cheap out on maintenance, especially on a 50k+ car. Will it hurt to swap brake fluid? No, but don't tell people it's useless when it isn't.

I almost forgot. You even mentioned coolant flushes are overrated.

I want you to swap out both the brake and coolant in the next 3-4 years and see how disgusting they are and tell me they're still good. Coolant is IMPORANT for our cars. If you don't swap it, guess your water pump and thermostat are going to go VERY early. Not to mention, your engine will now be prone to overheating. N55 are notorious for running hot.

Originally Posted by Bestodabest

If your friend was involved in a collision that resulted from brake fluid boiling, then that's an operator problem.

I've been seeing those daily inspection checklists for 11 years now. I'm the guy you come and see when a fault is found. Please stay in your lane.

I stand by my previous statements. Unless you can produce evidence of QL5 Vehicle Technician training, a 310S or 310T red seal certificate, then you should keep your opinion to yourself. Tell your idiot friend to stop racing on public roadways.

You don't become an expert on the matter a year after figuring out how to swap brake pads.

I'm going to have to agree with Bestodabest here.

I've never seen someone on the street get into an accidentally solely because their brake fluid boiled. Even under track use in the middle of an 90F summer, my rotors reach 350F at most and calipers are at 150-200F (measured about 1-2 minutes after coming off the track). Not nearly enough to boil brake fluid on the street unless if you're dragging your brakes the entire time.

I'm more inclined to believe that this "friend" got into an accident because of operator error than boiling brake fluid.

[Bestodabest]

Originally Posted by spitpilot

Let's get focused back on technical issues rather than "gut feel"....
Here's an excerpt from a technical article about brake fluid, meassuring wet and dry boiling points etc that covers the topic well IMO...

4.0 When to Change Brake Fluid?
Many motor vehicle manufacturers recommend
checking brake fluid every 12 months, or changing
fluid every 24 months. The amount of moisture that
brake fluid absorbs depends on a number of factors
including the type of fluid, humidity, type of
brake hoses, condition of the seals and mileage.
Brake fluid will absorb 1% or more moisture per year
of service life. A two year old vehicle will have 2 to
3% water in the brake fluid. 3% water reduces the
boiling point of DOT 3 brake fluid by approximately
175°F (97°C). 3% water in DOT 4 brake fluid reduces
the boiling point by 162°F (90°C). (See Chart
next page)
Generally, the type of driving should influence when
to change brake fluid. If the vehicle is used for
towing, is driven in mountainous regions, or has an
ABS system it would be best to change the fluid
sooner. All vehicles should have the brake fluid
changed when the water exceeds the minimum wet
boil point. Motor vehicle manufacturers may recommend
brake fluid changes at lower water content/
higher boiling point than shown on the chart. OEM
service recommendations should be followed.

BMW reccomends 3 years for first flush and 2 year intervals there after...same as Audi/Vw...both use Bosch braking components (ABS valve blocks.) so I'd bet that Bosch has given some input to the car makers here about how to keep their components in top operating shape...Interesting to note both makes switched to requiring only DOT 4 LV (low viscosity) fluid at about the same time a few years back....so I'd guess Bosch drove that change as well....

An excellent write up, however under normal conditions (street use) brake fluid shouldn't be boiling after 2 years. Even with 3% water absorption, the fluid is still significantly above the boiling point of water.

[Bestodabest]

Originally Posted by Polo08816

I'm going to have to agree with Bestodabest here.

I've never seen someone on the street get into an accidentally solely because their brake fluid boiled. Even under track use in the middle of an 90F summer, my rotors reach 350F at most and calipers are at 150-200F (measured about 1-2 minutes after coming off the track). Not nearly enough to boil brake fluid on the street unless if you're dragging your brakes the entire time.

I'm more inclined to believe that this "friend" got into an accident because of operator error than boiling brake fluid.

He's already admitted that his friend was traveling down an incline when the incident happened; probably rode the brakes the entire way down instead of selecting an appropriate gear. You hear about it all the time out west where they've started using run-away lanes for commercial vehicles.

[dreamspeed]

I don't think you will get into a catastrophic accident if you don't change your brake fluid in 2-3 years but it won't hurt.

A friend recently changed his brake fluid after 3 years and the reading on his brake fluid tester was less than 3% water.

I just changed my brake fluid after 4.5 years and it read over 5%.

[John in VA]

My father finally had his brake fluid in his Cougar XR-7 changed after 25 years! But he is & drives like an old man. When you drive your car daily the degradation in response/performance can be difficult to notice as it happens incrementally over time. If you drive in a spirited fashion, changing fluid every 2 years can keep you safe & protect the brake components from possible corrosion due to the hygroscopic nature of brake fluid. Brake fluid is cheap, and a pressure bleeder makes the job a breeze.

[spitpilot]

Originally Posted by Bestodabest

An excellent write up, however under normal conditions (street use) brake fluid shouldn't be boiling after 2 years. Even with 3% water absorption, the fluid is still significantly above the boiling point of water.

I should hope the fluid boils "significantly above water"! Ever measured brake component temps after a long downhill blast through some serious mountains?...Way above 212 F for sure...then throw in towing a trailer and you're dissipating some serious heat in "street use"...

But I'm thinking the more frequent flushing being required by BMW and other car makers today is more to keep sensitive modern ABS components in good health and doing their ABS/traction control duties, rather than being driven by brake fade considerations.

[Orion4]

For me, it simple. Change every 2-3 years to retain as long as possible a good conditioned brake system minimizing the chance of degradation and corrosion. It's cheap insurance on a safety system.

As noted the degradation of brake fluid has a number of variables: driving style, temp, ambient humidity, driving load, etc. I've disassembled some systems that have not had fluid changed in 7-8 years and the components are fine. Others have looked like crap after 3-4. Varies.

I choose to error on the conservative (non-political) side. To each their own and reap the "benefits" of your decisions!

[Bestodabest]

Originally Posted by spitpilot

I should hope the fluid boils "significantly above water"! Ever measured brake component temps after a long downhill blast through some serious mountains?...Way above 212 F for sure...then throw in towing a trailer and you're dissipating some serious heat in "street use"...

But I'm thinking the more frequent flushing being required by BMW and other car makers today is more to keep sensitive modern ABS components in good health and doing their ABS/traction control duties, rather than being driven by brake fade considerations.

This all boils down to proper operation of the vehicle (pun intended).

Driving through mountainous areas requires a certain driving technique that relies on correct gear selection over the use of brakes. There's no reason for you to suffer brake fade if you're driving properly.

What brake component were you measuring the temperature of during this "downhill blast"?

You think the manufacturer was more inclined to publish their brake flush interval to preserve system components (that will EASILY last beyond the warranty period), over pressure from consumer and government legislation and lawsuits?

[jparnes1]

Reviving this thread...a friend with a 2017 330 (B48 engine) told me that to do a brake flush in this car he thinks he needs to use software to perform the bleed. He has no traditional brake fluid reservoir and you have to perform the service by controlling the ECU. Can anyone confirm this?

[jcattletown]

Nice writeup. In your post, you said "My fluid was the same color so for the 1st one I flushed it till it was around 1/4 left in the reservoir, this ensured it was all new fluid in the lines." Is the first one the right rear one (the farthest)? Does that mean the longest line only takes about 3/4 volume of a full reservoir. Am I understanding you right? I am thinking about bleeding the brake system of my 2013 X5 E70 soon with the Motive bleeder. Because of the similar color for the old and new fluid, I just want to know the volume needed for the first bleeding without needing to add fluid to the reservoir, which could a PITA. Thanks.

Originally Posted by jdr78569

Pressure bleeder, simple and easy. They use them at shops as well; cant do wrong. Cant get anything back in the lines like tradition pedal pumping, it forces the fluids out only. Its quick simple and can do it with 1 person. Thats what I did.

You can purchase a Motive or Schwaben pressure bleeder and a catcher (or use a bottle and rubber hose). You can pressure bleed it with air or fill the container with brake fluid. I did it with air. 2 reasons; 1. it doesnt wear the rubber hoses while in storage and 2 if a connection pops loose it doesnt fling fluid everywhere just air. With the bleeder, catch bottle and fluid it ran me about 80 bucks if im not mistaken. Bought the schwaben 3 liter bleeder and catch bottle from ECU tuning and picked up DOT 4 fluid from BMW. So future times just need to buy fluid and not pay dealer pricing again and again.

You can make your own for around 20-25 bucks too. Lots of videos on youtube for it too.
http://faculty.ccp.edu/faculty/dreed...eder/index.htm

option 1 air
1. suck out or bleed the reservoir to a bit is left. Dont completly dry it out so prevent any pockets.
2. Fill it up with new approved DOT 4 fliud
3. put the pressure bleeder on snug and pump the bleeder to around 12-15 psi. This keeps a constant pressure and forces it out.
4. go to the bleeder and connect the drain hose. Open the line and drain it till the fluid color changes (if you have different color) OR drain till the reservoir is low but ENSURE it doesnt run out.
5. Continue to other brakes. ensuring you fill the reservoir to ensure it doesnt run out.
6. After bleeding all the lines top the reservoir off and your done.

When I bled mine the reservoir never ran dry while flushing the lines but i continue to monitor the reservoir. If you run it completely dry, its ok. You will just have to top it off and flush again to make sure you get all the air out. I topped off when going to the next brake. My fluid was the same color so for the 1st one I flushed it till it was around 1/4 left in the reservoir, this ensured it was all new fluid in the lines. The following ones was less and less. Having a different color fluid helps identifying when its all new.

Option 2 fill bleeder.
1. fill the pressure bleeder with the DOT 4 fluid.
2 *optional* suck out old fluid from reservoir and fill with new
3. place pressure bleeder cap on reservoir and pump 12-15 psi.
4. go to bleeders and flush the line
5 do this for all 4
6. release air, remove pressure bleeder and top off fluids if needed.

With filling the bleeder you dont have to worry about running out of fluid since the tank is larger and holds more.

Bleeding order, from furthest from reservoir to closest. reservoir is on driver side of engine bay
1. Passenger rear
2. Driver rear
3. Passenger front
4. Driver front

No coding is required but you will have to reset your brake fluid reminder.
1. push on, to turn on ignition not car
2. press and hold the trip reset (after the service reminders go away)
3. release trip button and put till you find brake flush
4. press and hold
5. will ask if you want to reset
6. press and hold till it resets.

You can reset oil and other services if you do them yourself as well.

[Kimbolee13]

What fluid should i use for my 2014 328i xdrive ? Can i use anything with dot 4 ?

[montr]

Originally Posted by Kimbolee13

What fluid should i use for my 2014 328i xdrive ? Can i use anything with dot 4 ?

DOT 4 LV

[Billfitz]

FWIW at this late point in the thread, the reason for changing brake fluid is to address the issue of the fluid becoming contaminated with water over time. The car has no method of measuring brake fluid moisture content, so to err on the side of caution it's a mileage based condition. If you'd rather know if a change is necessary get one of these and you'll be sure, one way or the other:
https://www.amazon.com/PTE-Tester-ca...CZ9TYVW7KRQ18S

[leejak]

What is the difference between the pentozin dot 4 and dot 4 lv....should we be using the lv in our f32?

[Billfitz]

LV stands for low viscosity. LV is recommended for BMW from 2003 model year on.

[leejak]

Originally Posted by Billfitz

LV stands for low viscosity. LV is recommended for BMW from 2003 model year on.

Ok, great...thanks...will go with LV

[VWAudi2BMW]

Just switched over to BMW from VW. ATE SL.6 was a good fluid for DD flushes on the VW / Audi's every two years. Was quick and easy with my Motive Power Bleeder. Is the SL.6 a decent option on a 328 / 330 not seeing track use?

[Billfitz]

SL.6 meets DOT 4 LV requirements, so there's no reason why you can't use it.

[wwilme]

Originally Posted by Billfitz

FWIW at this late point in the thread, the reason for changing brake fluid is to address the issue of the fluid becoming contaminated with water over time. The car has no method of measuring brake fluid moisture content, so to err on the side of caution it's a mileage based condition. If you'd rather know if a change is necessary get one of these and you'll be sure, one way or the other:
https://www.amazon.com/PTE-Tester-ca...CZ9TYVW7KRQ18S

So I did buy one of those gadgets and it’s says my 9 year old brake fluid has 0% water content. And it’s certainly not black or even dark colored. Car stops just as well as it ever has. Not sold on the 2-3 year/30k change out.