Bleeding brakes/ brake flush?

[alnoor15]

Currently driving a 2015 audi a4 with 42k miles and this saturday I am planning to install akebono ceramic brake pads, cross drilled and slotted rotors and SS stop tech brake lines on all wheels. I have been told that I need to have a brake flush and bleed my brakes.

First of all, what exactly is a brake flush and bleeding brakes? Do I need to do one or the other or both? What are the differences and benefits of each one and how much would it cost in labor?

[BMWManiac]

Currently driving a 2015 audi a4 with 42k miles and this saturday I am planning to install akebono ceramic brake pads, cross drilled and slotted rotors and SS stop tech brake lines on all wheels. I have been told that I need to have a brake flush and bleed my brakes.

First of all, what exactly is a brake flush and bleeding brakes? Do I need to do one or the other or both? What are the differences and benefits of each one and how much would it cost in labor?

Brake fluid absorbs moisture and should be completely flushed at least every 2 years.....a brake flush is replacing all of the brake fluid in your calipers, lines, reservoir, clutch line (if manual). Brake bleeding is part of brake flushing and the same process. You are bleeding AIR from the brake fluid. You do need to bleed while flushing.

I don't know how much shops charge. If you have any mechanical ability, you can do this. Put the car on jackstands or a lift. Remove all wheels. Get yourself a MOTIV brake bleeder. Fill with all new fluid (back a couple years ago, you could buy ATE Blue so you could see when the fluid changed). Go to the passenger rear and drain into something until the new fluid completely replaces old fluid. Then go to driver's rear. Then passenger front. Lastly, driver's front. There are multiple YOUTUBE channels that show this as well. Bottom line, you don't need to bleed the brakes when changing brake pads or rotors. You may need to top off the reservoir though. You do need to BLEED if you've remove the calipers, opened the caliper bleed screws, or are in the process of flushing. Since you are replacing the brake lines, YOU WILL NEED TO BLEED AND MIGHT AS WELL FLUSH the system.

[Audibot]

You're supposed to flush your brake fluid every 2 years or so, regardless of mileage, since brake fluid is hygroscopic and will absorb water, reducing its ability to provide stopping power without boiling off.

A brake flush is literally flushing out all the old brake fluid and replacing it with new fluid. Should help with pedal feel as well. Will be a definitive color change (old fluid will be darker while new fluid will be straw colored). Bleeding your brakes is done to remove air bubbles from the lines and calipers so you have a firm, consistent pedal rather than a spongy pedal or one that goes all the way to the floor. You'll have a lot of air in the system if you change the lines.

If you are changing out all the discs and pads, you can do a brake fluid flush WHILE you are bleeding the brakes. If you are doing the brakes yourself (or with a friend/relative), it's pretty easy to do. If you have a jack and jack stands to get at least one corner of the car in the air, you can use either a pressure or vacuum bleeder, or the two person method to bleed the lines and reservoir. I've heard mixed things about Audis and bleeding order (typically you work your way from farthest corner away from the master cylinder to the closest). Basically open the bleeder screw and push out all the old fluid until all the air bubbles are gone and the old fluid is pushed out. Then move to the next corner all the way around.

Plenty of YouTube videos you can check out. If you are paying for someone to do the whole brake job for you, labor will probably run $200-$300 or so if you are providing all your parts, or more if you don't have anything.

[jfo]

There are reports that say modern cars no longer have an issue with moisture entering the system through old hoses, etc. The real issue is copper contamination from the brake lines which are lined with copper. If the additive package in the fluid is broken down/depleted then the lining will start to corrode. Levels above 200ppm indicate it's time to flush and test strips are available to test by dipping in the master cylinder. You may want to do more research on this to satisfy yourself about the best approach.

Brakes do not need to be bled when changing pads or rotors, unless you are also opening the system by changing a brake line, etc.

[VAGLVR]

25yrs of driving . over 30cars total of close to 2 million miles . ive never ever flushed my brake fluid and ive never had a problem with moisture..

In college i worked at dealership.. Selling brake flushes was the dealers bread and butter.. 50% of the time they sold the service but never performed the job..

Of course if for whatever reason some how the fluid gets contaminated or theres a leak.. Then yes a flush would do good..

But otherwise its tottaly unnecessary.

[BMWManiac]

But otherwise its tottaly unnecessary.

This summer I flushed the fluid out of my Dad's 97 BMW with 155k miles that he just bought. The fluid was a dark brown. I could not disagree with you more. Maybe newer cars are better at it, and maybe 2 years is preventative, but I wouldn't say it is totally unnecessary.

[Smac770]

Had the dealer do a flush since the car was there for other reasons. Pedal feel had become a bit squishy in recent months and it had been 3.5 years since it was last done. $120 labor, $40 fluid was easier than acquiring the tools and knowledge to do it correctly. Pedal feel is good again. Audi can claim a 2yr cycle, but I don't bother flushing unless I have some reason to. The OP might as well, already there doing the bleeding, why mix 4yo fluid and new lines.

[jfo]

25yrs of driving . over 30cars total of close to 2 million miles . ive never ever flushed my brake fluid and ive never had a problem with moisture..

In college i worked at dealership.. Selling brake flushes was the dealers bread and butter.. 50% of the time they sold the service but never performed the job..

Of course if for whatever reason some how the fluid gets contaminated or theres a leak.. Then yes a flush would do good..

But otherwise its tottaly unnecessary.

There are also those who have never changed coolant, trans fluid, diff fluids, etc and never had a problem. You are a sample size of 1, so "totally unnecessary" isn't really meaningful. I believe a much longer period than 2 years is fine though. I did mine 4 years ago and a recent copper test is still negative and the fluid is still clear and clean. I 'm not concerned about moisture.

[Audibot]

While it's my opinion, I believe any fluid that goes through repeated heating and cooling cycles should be changed. Nothing is truly "lifetime", regardless of what Audi specifies (of course, its definition is different from what I'd consider lifetime).

Regardless of my opinion, however, OP is planning to change lines, meaning he needs to bleed the brakes, and should take advantage of this opportunity to flush all the old fluid out.

[JeriQo]

25yrs of driving . over 30cars total of close to 2 million miles . ive never ever flushed my brake fluid and ive never had a problem with moisture..

In college i worked at dealership.. Selling brake flushes was the dealers bread and butter.. 50% of the time they sold the service but never performed the job..

Of course if for whatever reason some how the fluid gets contaminated or theres a leak.. Then yes a flush would do good..

But otherwise its tottaly unnecessary.

ive had my car for 3 years now and havent flushed the brake fluid.
what can it possibly damage if its not changed?

[Audibot]

If your braking performance hasn't decreased, I wouldn't worry about it. I generally flush out all my fluid when I do pads and discs because it's cheap enough and easy enough to do, and gives me piece of mind. I'll be doing it soon on my C5 and C7 because I'm upgrading both of those brake systems (18Z front and B7 S4 rear, and D4 S8 F&R, respectively. Finding those 400mm fronts w/o being gouged is not easy).

[audrobotic]

The 2 year mark cant be that important. VW recommends 3 yrs. I think in real life the actual risk is small but it is there so car mfgs are hyper conservative in their schedules because of how directly linked to safety this is. That being said I feel pretty safe with a 3 year interval on the A4, especialy living in a very mild climate

[Novarider]

I've never changed brake fluid as a maintenance item or when doing pads/rotors however if I'm doing a line/caliper/wheel cylinder repair I'll flush the fluid.

[CONative]

If you’re already planning to add stainless steel brake lines, you might as well get the tools to do the flush. You’ll be losing some fluid and possibly introducing air into the system when you change your brake lines. Honestly it’s as easy as changing your oil (IMO) if you have the Motiv power bleeder and the fluid evacuation bottle. I think I picked up both for around $70 on Amazon. Then you have it for life and won’t have to pay the dealer or your Indy to do the job.


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[A4x]

Flushing is easy, and Audi recommends doing it every 2 years.

Here is what my old fluid looked like. Car was 6 years old at this point and I have no idea if a flush was done previously or not. I do know that the brakes did feel better afterwards.



New fluid:

[ps2cho]

It’s downright dangerous to say you should never flush your brakes.

Air and moisture get into the hoses, which changes and increases pedal manipulation. This split second difference could cost you a few extra feet of brake distance which could be life or death.

Although every 2-years is ideal, in reality you can push it to 3-4 years, but after that you are surely seeing additional pedal travel whether you notice it or not.