modern non-silicon brake fluid is hydroscopic on top of being paint unfriendly... which means it attracts moisture......
you have moisture in your fluid
The Asians and Domestic manufacturers realized that Americans would never go for the idea of changing brake fluid even though it has the hydro characteristics...... and it cooks operating at temps which can exceed 400F and at even higher temps can start melting down the seals
of course the temps do cause the fluid to deteriorate
add some corrosion inducing moisture the mix and it doesn't take long to have a nasty mess of pitted metal inside your stuff
so they sealed the system using a diaphram and the fluid would go quite a while of being cooked before it ever absorbed enough moisture....... I suppose from minute leakage and removing the cap to check fluid...... to rapidly turn corrosive
the euro's typically didn't play that game and if you neglect to service your brake fluid...... it will reward you with a hefty repair bill for caliper replacements at the very least....... but the flip side is...... if you change the fluid every spring as recommended....... the brake hydraulics can outlast the rest of the car
I've serviced more than one MB that had half a million miles and never had a single brake hydraulic component replaced
however....... it's very common to find jap bikes totaled due to brake hydraulic failure alone and the cost of fixing it as new..... being more than the bike is worth
usually the fronts lock up first
oh...... any moisture in brake fluid does obey gravity and go to the lowest point in the system to begin wreaking havoc
so now...... and for the last ten years...... it's been pretty common for a brake fluid flush to be sold or included in a service at most all vehicle service centers..... and yes even the domestic car places
I guess they finally decided they didn't mind if their techs made some easy money that would save their customers some as well
and I can recall being Mr Goodwrench 20 years ago....... you'd have been laughed out of the garage if you suggested changing brake fluid much less charging the 9 tenths flat rate it paid
you can flush the entire system with Brake Kleen® or denatured alcohol if you wanna get all that crap out but realistically...... just pump plenty of new DOT 3....... it should say on the reservior cover and I am pretty sure some use DOT 4 and I don't remember which way they will or will not mix
it's reasonably common to discover a new need to completely overhaul the master cylinders and calipers when they are cleaned with the alcohol or cleaner products...... the cleaned used ones just don't seem to take prisioners
in any event...... I'd say you have some dubious hydraulic internals due to these many factors and the fact you are having retraction problems
hopefully they'll cooperate with you and not get you hurt
be careful and make sure your rear is adjusted and working as well as you can make it
those calipers aren't the easiest ones in the world to overhaul even if they only need rubber
the master cylinders are easy
too bad all hydraulic brake components aren't made of 2205
Bugman said:
While trying to get the front brake to quit making noise on my little Honda, I decided to change the brake fluid, because knowing the PO, it was probably the origional 1974 brake fluid. It was still nice and clear though in teh resivour(and I mean clear, not slightly off like fresh fluid). So, we started pumping fluid out while pouring new stuff in. The fluid I got out of the system was cloudy white, and i noticed that the old fluid and the new fluid didn't mix(like oil and water). I used DOT 3, and I'd assume that the origional fluid was DOT 3, because the cap says to only use DOT 3 fluid. So why'd it go all funky on me?
