Porsche apparently recommends the brake fluid be flushed every two years. I don't track my 911 C4 and annual mileage is about 6,000. Is this really necessary?

 

Yup, brake fluid absorbs water and if you let it sit in there long enough it can cause corrosion in the braking system.

Its cheap and easy to do.

 

While I agree with you I can t help but think of cars I know going 100K and never touching this fluid. (very common if you ask the average person). And I know some systems may be more advanced. I don t think the OP has to worry at this point and may stretch it another year(to three years) with no issue IMO. I also agree that it s pretty cheap and easy if you are handy. I also have a low mileage car that I still do every two years or when I want a project to do. If I remember correctly Mercedes Benz was every 4 years just for comparison. OP didn t say when it was done last if at all? That would make a difference too.

 

Thanks....too old and creaky to try to change it myself. Cheap is a matter of perspective. $132 at the dealership, but worth it if it protects the system. I've never had a car in which I changed the fluid...just curious.

 

$132 will not be much if it saves your life the next time you press hard the pedal and get stopped before a disaster happens. Otherwise, you will get that spongy feeling under your foot and a few seconds to think about the fact that maybe ...maybe..... it would have been a good idea to change the fluid (at least once) in your brakes.

I hope I satisfied your curiosity.

Yves

 

Agreed. I've already had it done...just wondered if it was really necessary. It may be a common recommendation for all cars, but I've never had it done or had it mentioned by any dealer service department other than Porsche.

 

It is really important to do it. No jokes. I suspect that they did it in your back, whenever you took your car for maintenance.

Yves

 

+1. Brake fluid is hydrophilic. The more moisture it absorbs, the more likely it is to corrode your brake system. Increased moisture content also lowers the boiling point of the brake fluid, although that is only a significant issue if you track your car.

 

Have the clutch bled too if you have one as long as it's up in the air. May prolong the life of the slave seals.

 

important to take care of it. the clutch (MT) share the same oil. (997.1)

my porsche dealer told me it had to be change (2 years) I asked him if he could simply check the oil to know if it was due.
he came back: no need to change it, looks new!

 

You need a new dealer. You can't judge moisture content by a visual inspection. There are test strips and testing tools that can detect moisture in brake fluid. The two year change interval is a minimum recommendation. Cars that are tracked or driven hard require more frequent fluid changes.

 

don't know what test he did. maybe he simply look at it or did more advanced test. (like the strips you mention)

I was surprise to hear oil was good. he could have told me it needs replacement and I would have pay without asking questions...

I guess it also depend of how you drive and milage.

I bought the car and brakes were 80% good. sold it 3 years, 30k km later and they were at 75%.
I guess I was not a hard braker... downshift and rev-match was more entertaining IMO. :-)

but you are totally right, it is important on a 911.
I have a toyota matrix and brake oil is good for the life of the car.. lol

 

It's like health insurance... you don't buy it expecting to have to use it...better to have fully functioning brakes when you actually need it (track or no track)

 

Oh God. The fluid in the reservior looks new but the stuff that comes out at the bleed nipple will be discolored and not healthy looking at all.

 

Yes. I can't stress this enough, and I know I repeat what others have said but this is important, brake fluid absorbs moisture from the air and is exposed to air all the time, via the air vent hole and the 2 year flush/bleed schedule applies regardless of miles.

I can tell you that while I've never felt any change in braking behavior -- this on the street but there have been reports of odd even scary brake behavior on the track with past its flush by date brake fluid -- a brake and *clutch* fluid flush/bleed made a noticable positive difference in my Boxster's clutch action and shifting behavior.

Oh, the above was with brake/clutch fluid just 2.5 years "old".