I finally got around to a complete flush of the fluid. FL. FR. RR. RL. And I did the FL a second time because I was not sure it was running clear the first time. Some of the fluid in the cylinder was diluted fresh/old. But we're clear all the way around.

Took it for a drive with some power stops. 45mph to a stop as if a pedestrian was walking out in front of me. I never usually drive this way, but the brakes had felt a little soft in the past, and now they feel firm.

Is it my imagination, or does the new fluid, or a complete flush, or both, make that difference in feel?

 

New fluid definitely makes a difference. Old fluid contains air bubbles which makes your peddle mushy when pressed. You're not imagining things. The peddle is definitely firmer.

 

Not only possible air in lines also water. Brake fluid is hygroscopic which means it draws water from the atmosphere.

 

water vapor/moisture gets in the fluid (hygroscopic action) condenses and gets pushed thru the line to the caliper, where it turns to rust particles..

when you press the pedal you get brake fluid- which doesnt compress,
pushing water which does!
that results in a spongy soft feeling to the pedal as pressure is lost

You need to flush each caliper until its clean-clean, and all new fluid comes out!

TIP: remove most old fluid from master with a turkey baster- pour new fluid in slowly and it will sit on top of old (clean that screen drop in thing too)

as you flush, old comes out- then mixed, then all new
keep going after that

use 2 refills of master cyl res per caliper--at least!
total good job takes 1- 1.5 qts of brake fluid
if you used less than 1 qt its not done right

flush brake fluid every year from now on, to maintain good pedal
and keep moisture from killing expensive parts like calipers and master cyls

also do the ABS test if lines were open-(even if not, its a good idea to test)
from 45mph do full abs active stop to stopped (need gravel or water and swerving wheel

get back to 45 and repeat a 2nd time, if pedal firmer 2nd time, you had trapped air

If air was trapped in ABS controller- you just got it out and now its in the lines
probably found in LF but start there and do all to be safe

all new fluid is critical--any old fluid is junk!

 

Note if AIR is in the system you have a problem line or fitting
air does not belong at all after flush/bleed

moisture is a fact of life- wiki hygro and understand why its a big deal in brake fluid and not in others
hint: other fluids circulate and get hot enough to dry out--
brake fluid moves a fration of an inch forward, then returns back only when pedal applied
so it doesnt get the correct kind of hot

 

Very very true.

C1 was not as clear as C2 thru C4, so I redid C1.

Can't wait to try the brakes in a rainstorm on a big, big parking lot.

My tubing is black from the bleeder, transitions to opaque to the container.
I'm gonna shop for all-clear hose.

I'm also thinking the replacement caliper had a bleeder slightly smaller than the stock caliper bleeders.

Ever notice how you might loose a few drops onto the pavement at each caliper?
The street now has the tell-tail quad pattern. I'll use a mat next time.

 

carb cleaner, simple green, super purple- will clean up the street

the hose size is listed in the diy on here
if you use a hose on bleeder nipple it has to fit tight, the other end sits in a container with 1/2" -1" of new brake fluid in it
that way no air can get sucked back up the line!

you can also do it with a loose fitting hose--used to direct old fluid into a container

Close the bleeder fully after helper hits `down` (3/4 of travel to floor- place 2x4 under pedal arm to prevent over extension and damage to the master cyl oring)
which is the normal method anyway,,,,

reminder -flush the brake fluid every year from now on,,moisture is real,,parts are old,,
do what you can to protect the most important part of the car

 

absolutely it makes a difference. Your pedal will feel firmer and your stopping distances should improve as well

 

weak spongy pedal and weak stopping is HOW/WHY many find out its years overdue for a brake fluid flush