Brake fluid replacement

My grandaughter recently took her Honda Civic (2004) to a dealer and was told she neede her brake fluid removed and replaced. She asked me whether to do this, for a $99 price tag. I told her I hadn’t had this done to my cars in the past, and hadn’t seen any consequences. What say you?

Brake fluid absorbs water, which is why periodic replacement is recommended. Water can cause rust within the brake system, which is not good. The maintenance schedule in your daughter’s glove box (it came with the owner’s manual) will tell her how often to replace the brake fluid.

Honda was one of the first to list brake fluid replacement in the factory manual. Follow that manual’s recommendations (dealers often over-do it).

You only need to replace brake fluid periodically if you want to prevent rust and corrosion in the brake hydraulic system, and if you want to prevent the loss of braking ability under heavy use, as when driving in hilly terrain. It’s your call.

Seriously, however, all one has to do is to read the maintenance schedule that came with the car in order to know the answer to this question. If I recall correctly, it calls for a brake fluid change every 30k.

Brake fluid absorbs water, that’s why the master brake cylinder’s reservoir are sealed from the environment and air tight. I certainly wouldn’t lose any sleep over that. I’v never changed my brake fluid in any vehicle I’ve owned (and there have been plenty) and have never experienced brake failure. If I suspected it was contaminated, I’d change the fluid in a heart beat. Otherwise, I’d do it at 100k miles, regardless of what the owners manual says. BTW - my owners manual for my F-150 tells me to change my motor oil at 7,500 miles, but I do it at 3K miles. I understand the dynamics of fluid used in an internal combustion process vs fluid used in a hydraulic braking system.

I say follow the owner’s manual. If you disagree, please tell us why.

Reservoirs are not airtight. Look at the cap. There’s a vent hole. As the brake pads wear the fluid level drops and air takes its place.

I change mine every 3 years. Road race and rally drivers change it every year or more.

That’s a vent hole for the backside of the diaphram. It’s there so that the diaphram can extend down into the reservior as the fluid levels drops in response to pad wear. The master cylinder is completely sealed by the diaphram.

Take a closer look at the diaphram. It is formed into concentric rings of ever smaller diameter with detents to allow it to be fully seated or extend in steps to take up the volume created by the displaced fluid. If you let the fluid level drop far enough, it will extend out and need to be re-seated prior to adding fluid.

If you don’t know the maintenance history of the car, a quick check of the brake fluid color will indicate a lot. If it’s COFFEE COLORED (no cream!), it definitely has to be changed.

A Hundred Dollars For Bleeding Brakes And Replenishing $3 Worth Of Brake Fluid?
Where do you live, on the left coast?

Why did they recommend it? Was it based on the looks of the fluid, brake problems/repairs, age/miles, mechanic’s boat payment, etcetera?

First, let me say that you have received sound advice. I cannot find fault with any of it.

Although it might be a recommended maintenance idea, I’m pretty sure that it could be changed for less than 100 bucks, . . . way less. This is one of those big money makers for some shops. It doesn’t take long and it’s not rocket science. Even if they have bleeder equipment to get r’ done quickly, there isn’t a huge expense to the shop, here.

I’d be tempted to wait until the car needed other brake work, like new pads/shoes, and roll it all together.

Grandpa, I’ll bet you’ve never had major problems with brake cylinders or calipers caused by not replacing fluid. I hear you. However, it wouldn’t hurt, if it could be done at a reasonable cost. Call around and see if $99 is a good deal or not.

I’m going to get some flack over this post, but that’s my advice and I’m sticking to it.


Brake fluid is hygroscopic which means it absorbs water. Water in the brake fluid can and will rust out the metal brake lines, from the inside out, you will not be able to see it until it is to late.
I have seen metal brake fluid lines burst on at least 3 different occasions. Once it happened while the vehicle was pulling a boat out of the water on a ramp. What if that had happened backing a boat down?

Change the fluid bit shop for a better price.

It’s probably more important with antilock brakes. They are more sensitive and more expensive to fix than the old-fashioned kind so it is probably more economic to do some PM with them.

If you have it done make sure they bleed ALL the lines.
Places that are not honest just put new fluid under hood and do not bleed.
When they are done go to service manager,look at his name tag say he is terry say terry did you bleed all wheels? he will say yes and tell him you are going home and your brother,uncle or dad is going to check and if bleeders are not clean and damp you WILL be back.
When you bleed brakes you wipe bleeder off so no dirt gets in.
I have never see them done without getting fluid on them witch will make them look a little wet, this is how to tell they were done.

tell him you are going home and your brother,uncle or dad is going to check and if bleeders are not clean and damp you WILL be back…

That’s a bit confrontational don’t you think? Don’t act pissed for no reason. Go home and check, even try to crack open a bleeder and see if the fluid is dirty or clean. Then if the bleeders won’t open or if the fluid is dirty, that’s the time to get your hackles up.

Yes I may have went over board on that one.