Help! Brake Fluid Flush

I have a 2001 Nissan Xterra with 54,000 miles. How often should brake fluid be flushed? I am getting differing opinions/rates from repair shops. My brakes are squealing and the ABS light comes on periodically. I’m going to replace brake pads (these pads only have about 15-20K on them), and turn rotors, but do I really need to get the fluid flushed??


Does your owners manual call for a brake flush at any time? Probably not. This is just another way for shops to make an extra buck in most cases. I have owned several cars that traveled well over 200k in their life times and never had brake flushes. Just replace your pads and make sure your rotors are in good shape. Thats it.

I’ll check my owners manual tonight. Most people have told me that my fluid probably does not need to be flushed. When the Firestone on Kirby told me that, I thought it was wise to get a 2nd opinion. I’m glad I walked out of there without letting them do any work! Thanks for your response!

I replace my brake fluid every 5 years. Brake fluid absorbs moister,its this moister that ruins brake system parts from the inside.
I remocve the fluid from the master cylinder using a turkey baster. Replace with new and bleed till clear fluid comes out.

The brake system is sealed. Unless you have a leak, or you’re opening the MC reservoir for some reason, moisture won’t get into the lines.

Once every 5 years / 50,000 miles is cheap insurance for a VERY expensive ABS system. Brake fluid DOES get contaminated and degrades. Change it.

Its not in most owners manuals because it is usually done when the pads are changed. It should be a part of any brake job. As part of a brake job, it doesn’t add much to the cost.

Brake systems are NOT sealed systems. There is a hole in the master cylinder cover to allow air in and out to prevent pressure or vacuum from forming in there. Moisture does get in there and since brake fluid is hygroscopic, it readily absorbs the moisture. ABS systems need a good quality, not to badly contaminated,brake fluid.

is this the first time your brakes have been changed? just curious.

you could have the fluid changed, but i would be REALLY surprised if the firestone jiffylube or other such place would actually completely change all the brake fluid anyway.

i was at one shop and their idea of changing brake fluid was to use a turkey baster and suck the fluid out of the reservoir under the hood and replace it with new!! so i guess it depends what shop does the work.

In this case, the word flush seems to confuse people. Unlike a transmisison flush, a brake flush doesn’t mean hooking a machine to the brakes and pumping the fluid through. A brake fluid flush involves replacing the fluid in the master cylinder reservior with fresh, clean fluid, and then bleeding the brakes at each wheel until the fluid coming from the bleeder valve is clean, clear, and new.

This should ABSOLUTELY be performed no less often than once every 3 years. Mileage is really of no concern in this case. After three years, the ability of the brake fluid to resist boiling is heavilly degraded. DOT3 fluid (most commonly used) boils at only about 270?F once it’s three years old (brake fluid becomes approximately an additional 1% water for every year that passes while it’s in the brake system). Fresh fluid boils at well over 400?F, so you can see the problem here. If you live in the mountains, or regularly drive in stop and go traffic, the increased braking loads can build up enough heat to boil the old contaminated brake fluid, causing vapor lock and rendering the brakes useless.

As for replacing the pads and turning the rotors. When you replaced the pads, did you have the rotors turned? If you did, and the brakes are squeaking, and a good coating of Anti-Squeal on the pad backing plates doesn’t rectify the problem (and lubrication of the caliper guide pins if they weren’t done at the pad change), then don’t turn the rotors. That’s a waste of money. Replace them instead. If the rotors are causing a shimmy or vibration with the brakes applied, replace them. Don’t turn them. If neither of these cases apply, and you wanna turn them, then go ahead.


There have been several discussions in this board on this subject, with two camps offering differing views. I’m in the camp that brake fluid definitely absorbs moisture and should be flushed every 3 years.

It’s always been my observation that vehicles that got their brake fluid flushed were less prone to having their brake wheel cylinders or calipers get pitted on the inside. Not scientific, just one person’s experience.

It could be argued that these parts are inexpensive and that it’s cheap enough to simply wait till they get pitted and leak, and then replace them. That may be true, but it’s not true with ABS.


Brake fluid picks up water which contributes to corrosion of master and wheel cyinders which then leak and typically must then be replaced. Someone who lives in a very dry area might not have a moisture problem as quickly so it is not surprising to see differing opinions.

It does need to be changed. The word flushed can mean several things. It needs changed and adding to the cost by calling it a flush is just a wallet flush.

Note, you will not see any evidence of the need to flush it until it is too late.

Honda manuals recommend changing brake fluid every three years, many other manufacturers don’t mention it as a maintenance item. Since Honda’s use essentially the same brake systems and brake fluid as other cars, this has led to confusion.

The theory is that brake fluid slowly absorbs water, and in use, brake fluid (and brakes) get hot, and in some extreme cases, the water in the brake fluid can boil and you would lose braking. If this seems far-fetched to you, well, I guess the manufacturers other than Honda think so too.

Flushing the brake fluid is probably not a do-it-yourself operation for most people, because to do it right, you must, essentially, bleed all the brakes until all the old fluid has been removed. However, if you Google this, you’ll find a page where a guy recommends simply replacing the fluid in the master cyclinder (an easy job) multiple times, on the theory that the majority of the fluid is in the master cyclinder reservoir, not the brake lines, and eventually any water in the system will balance with the new fluid.

Contrary to another poster, I do not believe a regular brake job replaces any of the brake fluid.

By the way, I replace my brake fluid every 3 to 5 years, even on non-Honda cars. I think it costs about $100.

The squeal may be just a nuisance or it may be a signal that your pads are almost worn out. Since you have less than 20k miles on them, I would suspect the former. But someone should check to make sure. If the pads are still good and you can tolerate the squeal, I would wait for the next pad change to turn or replace the rotors.

The flickering brake light has nothing to do with pads or rotors and is more serious. It needs to be checked out immediately.

As others have said, conventional brake fluid is hygroscopic; that is, it absorbs water from the atmosphere. Resistance to brake fade decreases because the water reduces its boiling point. Also, the mixture is corrosive. Eventually, corrosion will cause the pistons to stick in the calipers. Then, you will need to repair or replace the calipers. Periodically replacing the brake fluid, by refilling the master cylinder reservoir and bleeding the old fluid out of the brake lines and calipers, is routine maintenance. It is much cheaper than new calipers.

Thanks for all of your responses! I’m thinking I might just suck it up and get the fluid cleaned, too. It’s an extra $100 with labor, but since I want to keep this car a few more years, it’s worth it.

To answer a few of the other questions - I had my brake pads changed in June 2003. The rotors have never been turned. The last time the ABS light came on and the brakes were squealing, Firestone just cleaned the brakes and all was good. I have talked to a few other Nissan truck owners and they have had a problem with the ABS light, also. They said they’ve had their trucks looked at numerous times and no one could find anything wrong.

If any of you know a good, trustworthy shop in Houston (near downtown), please let me know! thanks!

yes do it . when you got the car new the fluid was clear. now it is black. because the fluid eats the inside of rubber hoses you get rubber in fliud which cause a problem. also old fliud will make the hoses swell inside cause pressure problems and some times the calipers will not open all the back and pads rub on roters all the time causing pads to wear out soon and heat in pads causing loss of braking power. to hot and fluid will boil and then no brakes.