tapankd

Hello.. As per the maintenance books.. it says that Brake fluid flush should be performed every 20k miles or 2 years whichever comes first.. making it a part of Service B... I was just curious if you guys do Brake fluid flush every 20k miles.. I had mine done at 27k miles along with oil change.. Should i get it done again at 47k miles when i do my oil change... Thanks in advance.

gamma300C

Every 2 years for brake fluid was chosen I believe because that was the average length of time when the brake fluid moisture contents is in the high 3% range. I have no idea why that percentage is the cut off...suppose it has been shown to significantly effect braking in some study or more. If you want, Amazon has brake fluid hygrometers for about $10.00 and you can confirm if the H2O level is in the "need to change" range particularly if you are utilizing a Dealer/Indy Garage. I personally change out the brake fluid on my vehicles fairly often for something to do and the warm fuzzy feeling....a probable small waste of time/few dollars

tapankd

so should i do it every 2 years or every 20k miles..

gamma300C

I would chose the time parameter over the mileage myself.

white46

Correct. Brake flush should be time driven unless you auto cross the car often.
Having said that, I flush all the cars I've owned every 3 year and non failed yet. knock on wood.

tapankd

So my Last Brake Fluid flush was in December 2017.... So i guess i am good till atleast Fall 2019..

superangrypenguin

As per MB every two years

ItalianJoe1

Yeah the time is much more of an issue than the mileage, if you put 60k on the car in 2 years, I'd still say only do the brake flush once. It's about moisture absorption into the fluid lowering the boiling point, mileage really shouldn't matter.

M~Factor

edgalang

I originally did 20k mile/2 year intervals just so I can say I did it by the book when I was under the 50k mile warranty. Eventually the dealer pointed out my fluid was still good after testing (I'm currently averaging 17k miles a year) and I now I simply do the test myself and change when it reaches 3%. I test every 10k miles during an oil change and use Motul DOT 5.1.

superangrypenguin

How are you testing? Also, it's not generally advisable to be opening the brake fluid reservoir as everytime you're doing so you are exposing the fluid to air, and the fluid is hydroscopic.

ezshift5

[QUOT hydroscopic.[/QUOTE]

Actually, these days it just may be hygroscopic...............

ez

superangrypenguin

Actually, these days it just may be hygroscopic...............

ez[/QUOTE]
Well done

tommiett

Maybe I'm just lucky. But the only time I change my brake fluid is when I change the brakes on any of my cars. Zero brake failures in over 45 years and a ton of cars... I'll be changing the brakes on my 79 Corvette this winter. Will test the brake fluid before I change it. Might be OEM.. but still stops just fine. It just seems for a closed system.. if your getting high water content in your closed system, you have other issues to look into. Testing is the key.....

I'm sure I'll get rocks tossed at me, but 20k brake fluid change is like the oil change places telling you to change your oil every 3k. Good for your car, but overkill. IMO.. <------ Going into hiding now.

You do what you think is best for your car and pocket.

capt_paul

The brake fluid flush interval is 24 months, and not based on Service A or Service B. I is usually performed with either service as it will eliminate an extra trip to the workshop.

capt_paul

The Mercedes brake system is more precise than the 79 Corvette brake system. If you don't perform the brake flush as recommended by the service book, you risk ruining your $1500 ABS control unit. Cheap insurance to do recommended services, regardless of you may have done on other cars.

edgalang

No rocks will come from me (at least big ones ). IMO as long as you have a consistent and trusted way to test, then changing based on an informed decision is acceptable (but god forbid if you recommend anything different that "manufacturers" suggested" intervals here, you will have rocks thrown at you, so I won't even participate in that debate). Coincidentally, I recently tested my wife's Lexus and her fluids tested at about 2.75% water content, so I'll be looking to do a flush next oil change and we're sitting at about 5.5 years on the original fluid.

ItalianJoe1

I've seen fluid that was black like diesel oil and still works, is it right, no, but many manufacturers don't specify such often brake fluid changes and the cars are just fine. There are rarely brake system failures due to infrequent fluid changes, it's just not a big deal, but it's a safety system and MB is nothing if not overly concerned with safety.

Tom in Austin

Throw some rocks over this way ... I have rarely changed fluid on my cars and the brakes work well on all. I think automotive brakes have an immense margin of safety in ordinary use. The worst complaints you hear from people about their brakes are pad dusting and squealing. I think if you keep up with pad replacement and turn or replace rotors when needed you are most of the way home ...

capt_paul

Tom in Austin

Good point on the rotors, I don't know MB rotor specs (yet), but on my Porsche there's only a 2 MM difference between new and minimum thickness, and to machine them takes 1 MM off each side .... so effectively, Porsche rotors "cannot be turned" ... perhaps Mercedes is the same way?

Nicholi2007

I don't have the equipment nor garage to perform DIY. Then you need to dispose of fluid which is a drive.

I was thinking of having a mobile mechanic come out. $113.49 for labor.

The dealer want $235.

My concern is the moisture part of it.

Is there any advantage of using the dealer over a mobile mechanic?

The liquid is already brown.

chassis

The dealer has training. Does the mobile mechanic have training? How would you know if he has training?

Nicholi2007

He does. I use YourMechanic for some stuff. I would never use some mechanic off Craigslist etc...

gamma300C

The only reason I have used a Dealer in the past (rarely) has been when I thought the ABS accumulator/system needed flushing too since you needed usually proprietary software to activate the system in the shop. Will you supply the correct DOT 4 LV fluid or rely on the mobile mechanic to know what your MB requires ?