99 Legacy Outback rear brakes barely working

[AndrewP]

Hi.
The rear brakes on my 99 Legacy Outback are barely working. They are
disc brakes and the first clue was the brake pedal is very soft and
needs pushing a long way to get much braking. The second clue was I
raised up the back of the car and even with someone pressing on the
brake I can turn the wheel with my bare hands. I have bled the brakes
at all four wheels and the master cylinder, as well as changing the
rear pads (which were only half worn) but no difference. The rotors
look ok, although not as shiny as the front ones. I'm wondering about
whatever the valve or whatever it is that splits the braking force
between front and rear. By the way, the car is manual transmission
and the handbrake (E-brake) is fine.

Any thoughts?
Andrew.

 

[Carl 1 Lucky Texan]

Hi.
The rear brakes on my 99 Legacy Outback are barely working. They are
disc brakes and the first clue was the brake pedal is very soft and
needs pushing a long way to get much braking. The second clue was I
raised up the back of the car and even with someone pressing on the
brake I can turn the wheel with my bare hands. I have bled the brakes
at all four wheels and the master cylinder, as well as changing the
rear pads (which were only half worn) but no difference. The rotors
look ok, although not as shiny as the front ones. I'm wondering about
whatever the valve or whatever it is that splits the braking force
between front and rear. By the way, the car is manual transmission
and the handbrake (E-brake) is fine.

Any thoughts?
Andrew.

I'd be suspicious of the master cylinder. Get it looked at by a pro - soon.


Carl

 

[AndrewP]

Thanks Carl, but isn't the fact that the front brakes are fine but the
back ones barely having any effect at all a sign that it's something
after the master cylinder? I am wondering about how the braking force
get distributed between front and back and whether whatever valve or
electronics control this are not behaving.
Andrew.

 

[Carl 1 Lucky Texan]

Thanks Carl, but isn't the fact that the front brakes are fine but the
back ones barely having any effect at all a sign that it's something
after the master cylinder? I am wondering about how the braking force
get distributed between front and back and whether whatever valve or
electronics control this are not behaving.
Andrew.

Some cars have diagonally split hydraulic circuits - I dunno about soobs
though. There probably is a proportioning valve for front and rear, that
may be the problem. Hopefully someone else will chime in with experience
here.

Carl

 

[strchild]

All the soobs I've owned and driven have had the diagonal split for the
breaks listed in the manual.

~Brian

 

[johninKY]

The system is the diagonal type so since the fronts seem to be working,
this should eliminate the MC as the problem. My guess is there is still
air in the lines coupled with sticking rear calipers.

 

[AndrewP]

Thanks everybody - I'll bleed again at the weekend to make sure and
have a check of the calipers!
Andrew.