Brake fluid change interval?

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The condition of he rest of the brake system has an effect on fluid life too. Mainly cracked/perished hoses and I'll-fitting reservoir caps allowing air, and with it moisture, into what should be a sealed system.
 
Originally Posted By: 69GTX
I drove dozens of cars over 38 years before I did my first brake flushes ever in 2015....figured I needed to get with the BITOG philosophy.

It's a good idea, but yes, lots never get changed. It's pretty easy to say to heck with it when bleeder screws are all rusted in.
 
Originally Posted By: beanoil
New 2016 RAM ProMaster City (FIAT Doblo with RAM badges), fleet vehicle. Maintenance schedule required by fleet is a brake fluid change every 20,000 miles.
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That will be twice a year at my current driving habits, and about 8 times over the expected life of the vehicle.
Brake inspections, tire rotation, and oil change every 10,000.


Brake fluid change based on mileage rather than time doesn't appear to make much sense. Perhaps they just spec. it that way for administrative convenience, to fit in with other mileage based operations.
 
Originally Posted By: Olas
The condition of he rest of the brake system has an effect on fluid life too. Mainly cracked/perished hoses and I'll-fitting reservoir caps allowing air, and with it moisture, into what should be a sealed system.


Operating environment probably makes a difference too. Very humid here, and the fluid in the above pictures may never have been changed in the 27 year life of the vehicle up to that time.

In the desert, maybe you could get away with that?
 
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Typically I change the fluid when I buy the vehicle and then every two years after that.

It's cheap, and should keep the braking performance from degrading as well as extending the life of the master cylinder & slave cylinders/calipers.

As well, changing it regularly keeps the bleeders from rusting in place. If they are seized, I wonder if it helps to siphon some fluid out of the MC and refill with new fluid? Will the new fluid migrate down through the brake lines to the calipers? That is, if you did this regularly would you wind up renewing most of the fluid eventually?
 
Originally Posted By: Number_35
Typically I change the fluid when I buy the vehicle and then every two years after that.

It's cheap, and should keep the braking performance from degrading as well as extending the life of the master cylinder & slave cylinders/calipers.

As well, changing it regularly keeps the bleeders from rusting in place. If they are seized, I wonder if it helps to siphon some fluid out of the MC and refill with new fluid? Will the new fluid migrate down through the brake lines to the calipers? That is, if you did this regularly would you wind up renewing most of the fluid eventually?


Depends what you mean by eventually, but it'll be a long, long time because its a long, long way.

I'd think that dirt/dirty fluid will probably stay put, but there might be some diffusion and hence removal of water.

If I was in that situation I think I'd replace the rusted up component if I couldn't get it apart.
 
Originally Posted By: Number_35
Typically I change the fluid when I buy the vehicle and then every two years after that.

It's cheap, and should keep the braking performance from degrading as well as extending the life of the master cylinder & slave cylinders/calipers.

As well, changing it regularly keeps the bleeders from rusting in place. If they are seized, I wonder if it helps to siphon some fluid out of the MC and refill with new fluid? Will the new fluid migrate down through the brake lines to the calipers? That is, if you did this regularly would you wind up renewing most of the fluid eventually?



I've been thinking the same thing as a quick fix to put off doing it properly. I doubt that new fluid would migrate very far but the absorbed water in the system should migrate from the old fluid into the reservoir giving an overall reduction in % water content in proportion to the respective volumes. What decided me not to bother trying it was the fact that water content is only one issue of concern. The other is that the corrosion inhibitors in the old fluid will be all used up and as I didn't think the new fluid would move very far I couldn't see the new inhibitors being distributed throughout the system.
 
I change it every 2 years in my street cars; the track rats get fresh DOT4 every 6 months.
I'm reminded of what I once heard a European automotive engineer say:

"The difference between European drivers and American drivers is:
European drivers don't care if the brakes squeal- just as long as they stop the car.
American drivers don't care if the brakes stop the car- just as long as they don't squeal."
 
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