I've notice over a period of about 3 months my brake pedal startedto feelmushy, in fact ifi pressed on the pedal and held the pressure the pedal goes almost to the floor.
Thinking that air got in the line, i replaced the brake fluid with Super Blue.....still mushy
Only other part to replace is the master cylinder....I've just now replaced the cylinder and again replaced the brake fluid, went for a test drive.....the brake pedal is still mushy.
What else could itbe, nothing is leaking
Thanks for any help

 

Bleed the rears again really good.
The rears tend to hold air.

 

For years I used a vacuum bleeder. Lately I have gone to a pressure bleeder and it does a better job. The problem with depressing the brake pedal when bleeding brakes is that you force the master cylinder's piston into an area of the bore that is generally pitted/rusted which then causes a failure down the line. I agree with TECH re: the rear lines and calipers need more attention when bleeding.

r.

 

The procedure i use to bleed my brakes is with the pump typepressure bleeder which i bought from IPD.
I took Tech's suggestion and did the rear brakes again, flushing at least 8 to 10 oz. on each brake. Using clear tubing on the bleed valve i saw no evidence of any air bubbles.
Sooo after this second bleed the mushy pedal remains.
Now during normal stop and go traffic the brakes work fine, however, when ijam on the brakes at 50 or 60 mph theres a delay before they grab, once they grab the stopping power is good, its that delay which should not be there.
Thanks for the input.

 

Did you also bleed the ABS pump assembly?

 

Tech,
You got me on bleeding the ABS Pump....I'm aware on some luxury brand cars theres a bleed valve at the ABS Pump, not on my 00 C70.
So the next question is, how do I do it ?
Again, thanks for the help.

 

You can let it gravity bleed by loosening the lines one at a time and letting the fluid flow out.
I always start with the bottom and work up.

Then try bleeding the brakes again all around and see if it helps.

 

TECH, do you think he may have a vacuum leak?? The pedal goes down and then he has some braking...................

r.

 

NO usually a vacuum leak or bad booster will be a hard pedal.

 

.............I was thinking along the lines of the booster. I had an issue in a Cadillac years ago where the booster had a diaphram leak that would allow the pedal to sink before I had a firm pedal..............

r.

 

Thanks, Tech and reg, for your effort helping me solve this brake problem.
After bleeding the complete system 3 times, using almost 3 liters of Ate Super Blue, plus the time and money for the brake fluid and new master cylinder, I'am giving up for now.
I'll tackle this problem at some future date.