# Changing brake fluid



## Camcruse (Oct 4, 2011)

Unless I missed something in the 2012 manual. Nothing mentioned about changing brake fluid.


----------



## jblackburn (Apr 14, 2012)

DOT3/4 is fine. Typical brake fluid life is ~3 years. It is hydroscopic and absorbs moisture.

Suck the fluid out of the reservoir, then refill with new stuff, and bleed til it runs clear at each corner of the car, keeping reservoir filled.

A Mitivac is a great tool for bleeding brakes alone.

Don't half-ass it.


----------



## diesel (Jun 8, 2013)

It's one of the most overlooked service items on a car. Not changing it can eventually lead to brake failure under hard braking that heats things up, when the fluid has so much water in it that it boils and the pedal goes to the floor because the air bubbles from the boiling water won't compress.


----------



## XtremeRevolution (Jan 19, 2012)

ProDigit said:


> I'm at the point of changing my brake fluid.
> Got 50k miles, and rear brakes are squeaking,
> Pads on the front, and just replace the rear shoes too.
> 
> ...


Easiest way to do it is to get a quart bottle, get a 1/4" ID clear hose, and drill a hole in the cap of the bottle for the outer diameter of the hose. Then, just unscrew the bottle a little. 

Loosen the bleeder screws with a 10mm wrench, then push the 1/4" clear hose over the bleeder screws. Place the bottle somewhere visible and start pumping the brakes. When you start seeing clear fluid, you know you're good to go, so tighten the bleeder screw, pull the hose off, then finish tightening the bleeder screw till it's snug. 

This is an easy way to bleed all 4 corners alone, because with a long enough clear hose (3 feet), you can always see when clear fluid starts coming through, and the hose is tight enough on the bleeder screw that you don't get air bubbles back into the brake system. 



Camcruse said:


> Unless I missed something in the 2012 manual. Nothing mentioned about changing brake fluid.


Check the more updated manuals, it's in there. I forgot what the recommended service was, I think 45,000 miles.


----------



## AzSandSlinger (Sep 10, 2015)

diesel said:


> It's one of the most overlooked service items on a car. Not changing it can eventually lead to brake failure under hard braking that heats things up, when the fluid has so much water in it that it boils and the pedal goes to the floor because the air bubbles from the boiling water won't compress.


Bingo. You never realize how important it is to flush your fluid until the emergency occasion you need those brakes to work. It only takes one incident and you'll never skimp on changing fluid ever again. Just hope it's nothing serious when you learn that lesson.

I bought this $10 kit from AutoZone. Has a small bottle with a magnet (to mount the bottle) and all the hoses and adapters you need. I bled my entire system in roughly 10 minutes with valvoline synthetic DOT 4. All without a spot dropping onto the driveway. Lol


----------



## ProDigit (Aug 31, 2015)

:mellow: !!

My brake fluid is 6 years old!


----------



## NickD (Dec 10, 2011)

With BMW, says once per year, I feel every three years is sufficient, the major problem is ABS, can get gummy and stick those solenoid valves. If this happens, have no brakes at all.

Use vacuum bleeding, my Mason Jar with two quarter inch tubes soldered to the lid and a hand operated vacuum pump, clear hose, remove the bleeder first and coat that with Permatex non-hardening gasket maker. Keeps air from flowing in. Rear of the car is on oil changing ramps, no problem in reaching the bleeders on the front. Have to keep that reservoir full with fresh brake fluid.

If you don't, will have problems getting air into the ABS, with older vehicles, could hot wire the ABS pump, can't do this on this new stuff, need a scanner now to activate the pump. Sequence is RR, LF, RL, then FR, just pump out each one until the fluid looks clean. 20 minutes at the most and you know its done right.

Read debates on DOT 3 or 4, 3 has a higher boiling point, 4 more corrosion resistant, but sure a lot more expensive, so just stuck with 3 for many years now. Whatever this stuff is, can clean my bottle with soap and water for the next time. Indubitably hygroscopic.


----------



## weimerrj (Dec 4, 2011)

diesel said:


> It's one of the most overlooked service items on a car. Not changing it can eventually lead to brake failure under hard braking that heats things up, when the fluid has so much water in it that it boils and the pedal goes to the floor because the air bubbles from the boiling water won't compress.


Point of order: it's not that the steam won't compress, it's that it will compress too *easily*.


----------



## AutumnCruzeRS (Sep 10, 2012)

NickD said:


> Sequence is RR, LF, RL, then FR, just pump out each one until the fluid looks clean.


Is this the sequence for newer vehicles? I thought it was farthest from the reservoir first to the closest as in RR, LR, FR, FL.


----------



## jblackburn (Apr 14, 2012)

AutumnCruzeRS said:


> Is this the sequence for newer vehicles? I thought it was farthest from the reservoir first to the closest as in RR, LR, FR, FL.


That's what I've always done.


----------



## money_man (Feb 25, 2014)

That's why everyone needs to buy a snap on scanner. Saves a lot of grief


----------



## Ledx33 (Jan 13, 2021)

jblackburn said:


> DOT3/4 is fine. Typical brake fluid life is ~3 years. It is hydroscopic and absorbs moisture.
> 
> Suck the fluid out of the reservoir, then refill with new stuff, and bleed til it runs clear at each corner of the car, keeping reservoir filled.
> 
> ...


What happens if i use dot 4?


----------



## weimerrj (Dec 4, 2011)

Ledx33 said:


> What happens if i use dot 4?


Not much. DOT 5 is the really different stuff and can be a problem with older brake systems.

However, DOT 4 absorbs more moisture than DOT 3, so you will have to replace it more often.


----------



## weimerrj (Dec 4, 2011)

But it is all tradeoffs - DOT 4 resists boiling (and thus is better at the extremes) better than DOT 3. https://www.autozone.com/diy/brakes/dot-3-vs-dot-4-brake-fluid


----------

