Brake/clutch fluid: crazy to change it, they say!

[440Magnum]

Originally Posted By: mva
Originally Posted By: eljefino
^ Getting everything nice and hot won't help the water in your brake fluid. Though I guess it will dehumidify under the hood where the MC reservoir "breathes".

Brake systems do not "breath" outside air. They are sealed with a flexible rubber cover that allows level changes in the master cylinder.

And I would argue that getting all 4 wheels hot does drive away any moisture from road spray that might get anywhere near the caliper piston seals and thus work its way into the system there.

 

[Market525]

I'm surprised that no one has made the correction so far in this thread -- I think the water absorption term for brake fluid is "hygroscopic" not "hydroscopic".

 

[Trav]

The moisture strips i have here are old and made by Wagner.
I don't know if they are still available.The new ones only test for copper.

I am looking at this one,it seems like it will do the job for cheap money.

http://www.amazon.com/Storm-Central-Electronic-Tester-STO3S121/dp/B000HI2BL6

 

[ltslimjim]

Okay, I'm new to the brake/clutch fluid game. Would just 'repeatedly' bleeding the clutch/brake and topping off at the master cylinders for each suffice...how does one actually 'change' the fluid? ...and would doing the above help at all?

 

[SubLGT]

Originally Posted By: dparm
You don't change brake fluid because it turns dark, you change it because air and water slowly enter the system.................


And to refresh the corrosion inhibitors that get depleted over time.

http://brakefluidtest.com/bm~doc/industry-adopts-brake-flu.pdf


"Dissolved iron appears in the brake fluid after the initial amine corrosion inhibitors are significantly depleted
and dissolved copper levels rise to around 200 ppm. According to the same report, by the time you see significant
levels of iron in the brake fluid, severe corrosion is active. The moisture content of the brake fluid also plays a role
in this process, but not the way you might think. According to the report, as brake fluid absorbs moisture, it will
result in the precipitation of copper oxides and the formation of hydrogen ions causing corrosion of iron
components. Once iron corrosion begins, copper acts as a catalyst to speed corrosion."

 

[HTSS_TR]

Originally Posted By: ltslimjim
Okay, I'm new to the brake/clutch fluid game. Would just 'repeatedly' bleeding the clutch/brake and topping off at the master cylinders for each suffice...how does one actually 'change' the fluid? ...and would doing the above help at all?

How do you bleeding the clutch/brake ?
1) via bleeder screws ?
2) siphon fluid from reservoir ?

If you do method 1 then it is good for 2-3 years.

 

[NateDN10]

Originally Posted By: ltslimjim
Okay, I'm new to the brake/clutch fluid game. Would just 'repeatedly' bleeding the clutch/brake and topping off at the master cylinders for each suffice...how does one actually 'change' the fluid? ...and would doing the above help at all?

That's basically what a brake fluid change is. Keep bleeding at each wheel until fresh fluid comes out.

 

[Craig in Canada]

Originally Posted By: ltslimjim
Okay, I'm new to the brake/clutch fluid game. Would just 'repeatedly' bleeding the clutch/brake and topping off at the master cylinders for each suffice...how does one actually 'change' the fluid? ...and would doing the above help at all?


You want to replace all the fluid in the system with fresh fluid. This is generally done by extracting the fluid from the reservoir, filling with fresh, and then repeatedly bleeding the brakes and clutch (while topping up the master cylinder) until fresh fluid is coming out all of the bleeders.

This procedure will not bleed the ABS loops on your vehicle (if equipped) so you need to either activate the ABS system with a diagnostic computer, or get out there on something slippery and get the ABS working. This will mix the old fluid in the ABS loop with the fresh fluid in the rest of the system.

This mixing is one of the reasons I don't like to leave the fluid change until the absolutely last moment. The "average age" of the fluid in the whole system, including the ABS loops, is newer. If I waited 3 years between changes then the stale ABS loops (which almost never get activated on my vehicle) would have really old fluid in them which would them eventually one day get mixed into the fresh fluid in the rest of the system. If I change fluid annually it's all in much better shape, even in the ABS system.

 

[Kestas]

For people new to brake bleeding, don't ever let the master cylinder go dry, or else you'll have to bleed the master cylinder separately. This can be difficult.

 

[Carbuff]

^^^^
I usually activate the ABS after bleeding/replacing fluid. I think it's good practice. Couldn't hurt!

All the ABS equipped cars I have owned do a test (pump activation) at the start of each trip (usually when the car's speed gets up to about 10 MPH). Still, this is just a quick pulse so a more prolonged activation is beneficial, IMO.

 

[ltslimjim]

Thanks for the tips guys. I bled the brakes when doing a brake change before, but just enough to encourage any air out and would top off the cylinders up top. I never repeatedly did this while adding new fluid until only new fluid came out. I'll probably do this when I have to replace the rear drum brakes on the Civic again(aftermarket cheap shoes need to come out of the drums).

 

[tonycarguy]

I used to do it every 4 years but now I do it every 2 because it's easy to do and cheap plus I always look for reasons to work on my cars (modern cars break down so infrequently, I only get to do basic maintenance on them). If you live in a very humid climate, I'd do it more often, though.

If you're tracking the car, then do it every 6-12 months