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Brake fluid

Is it neccessary to change and flush brake fluid when it becomes dark. The car in question is a 2002 Honda CRV

Recommended,even before it becomes dark,required? I must say no,even though it hurts to say no. Fluid replacemt does offer better brake system performance and a “hedge” against hydraulic parts leaking,but not flushing will not lead to catastrophic brake system failure.

What does it say in your owner manual or service guide?

The brake fluid should be replaced at the interval listed on the maintenance schedule. Your CR-V is probably overdue. Flushing the fluid removes moisture, which can cause rust in the brake system, which you don’t want.

Yes, it needs to to flushed. Brake fluid is hygroscopic which means it absorbs water and water in the brake lines can rust a hole in the metal line. It happens and can lead to crashes if the line busts.
This happened to a buddy of mine on a boat ramp. YIKES!!! I also saw it happen to a couple of other cars.

In addition to rusting the brake lines (I had a 1970 VW Bug that rusted out it’s brake lines, really exciting when that happens. It took out the whole braking system and it could have killed me.) but there is a second reason. Even if it does not rust out the lines, water can collect in a low spot and freeze in this weather. Same problem, you have no brakes.

Most of us consider brakes very important and we hope you do too.

A cheaper alternative to flushing it to replace the brake fluid in the reservoir more frequently, say every year. Easy to do at home, just dispose of it properly and keep it off the paint!

While I agree with some of the above responses, I really doubt a car 6-7 years old can expect to have brake failure if the fluid isn’t changed. On a 1970’s VW, I’d certainly be concerned about changing the fluid if I didn’t expect it was changed. I have never seen brake cylinders leaking on a 6 year old car, whether or not they’ve had their fluid changed. If you have the money and it will make you sleep better at night, by all means get your fluid changed. If I wasn’t going to do it myself, personally I’d be more worried about the grease monkey in the shop stripping out a bleeder screw or not properly tightening up a bleeder screw or line than I’d be worrying about brake fluid contamination. Yes the fluid might capture moisture over time, but the brake system is a sealed system (hence the rubber seal in the lid of the resevoir), so the amount of water that will get a chance to contaminate the fluid is pretty insigificant in the big scheme of things. Of course that is just my humble opinion, and you’ll get as many opinions as mechanics you talk to.

I am really surprised that nobody mentioned the other result of the hygroscopic nature of brake fluid.

When brake fluid is diluted by moisture that it has absorbed from the air, it will boil when the brakes are subjected to heavy use–such as when driving in hilly/mountainous terrain. When the brake fluid boils, you suddenly lose braking ability. So–imagine coming down a long hill and not being able to stop the car. That can happen much earlier in a car’s life than rusting out of the brake lines and is a significant safety hazard.

The bottom line is that moisture in brake fluid is a very bad thing and the only way to prevent either of these damage scenarios is to flush/replace your brake fluid at least every 3 years/36k–as is specified by most of the Japanese car manufacturers.

Those who ignore the maintenance recommendations specified by a car’s manufacturer inevitably come to regret their lack of maintenance.

I really doubt a car 6-7 years old can expect to have brake failure if the fluid isn’t changed.

I agree with you but keep in mind that doing it when recommended will keep it at bay for years. Doing it to late (you won’t be able to see when it’s to late) is still to late and flushing will not correct any unseen rust.

With that said there are 3 good reasons to flush brake fluid.

  1. to keep moisture from freezing in the lines.
  2. to keep moisture from boiling in the lines.
  3. to keep rust out of the lines.

VDCdriver is exactly right of course.
Not only can aged fluid boil it can also vapor lock. Some Harley motorcycles were even known to suffer rear disc brake lockups at speed due to boiling brake fluid. The recommendation on those now is DOT 4 or 5 whereas it used to be DOT 3.

A lockup almost happened to me once while traveling near Mt. Rushmore on my Harley and it did happen with a friend of mine. He was riding along about 65 MPH on a level highway with not a care then all of a sudden, bang, and he skidded to a halt with the rear wheel locked. After cooling down it was fine.

While this will not hurt, it is not sufficient.  It really needs to be don't by the book.  Modern brakes vary and with ABS and stabilization have different needs so be sure to check the procedure for replacing he fluid for your specific car.

the general rule of thumb is:every two years.ABS brake systems are really fussy,you must keep fresh fluid,otherwise when you slam on the brakes in an emergency,your brakes might not function to their best ability.