mazda mpv brakes

I've been a licenced mechanic since 1971 and I am since retired and
have forgotten something obvious about brakes.

My kids Mazda MPV 4WD with rear wheel "ABS" has a low brake pedal. I
took the master cyl off and stripped it down, washed it out, rubbers
looked good, cylinder clean and smooth, re-assembled and began to
bleed the brake system. I got no improvement in the brake pedal -
still way too low.

Rear drums removed, shoes & hydraulics inspected, brakes adjusted
manually to "just" rubbing. Front pads will need replacement
sometime this summer, but still serviceable. No leaks in any of the
cylinders or calipers. Rear brakes bleed on the left side only - the
right side has no bleeder, but another line going to the left side
which has the bleeder. There is a bleeder on the "ABS" module that
feeds both rear brake cyls.

I must be missing something really obvious, and I can't for the world
of me think what. Before I go and strip everything down to nothing,
I need someone with the "obvious" answer.

Thanks

Pete

You say there is no bleeder on the right side? You always need to bleed
both wheel cylinders, starting with the one with the longest line (furthest
from the master cylinder). I have had cars that the only way I could get
them to work was with a pressure bleeder. How are you bleeding the system?
The best way is to have someone press the pedal, crack open the bleeder a
little, when the pedal goes down to almost bottom have the person say "O.K."
and tighten bleeder. Make sure they don't let up on the pedal till you say
"O.K." that you have the bleeder tight. Repeat the process until the pedal
gets better. Are you sure you have air in the line? Usually the pedal will
be spongy with air in it. You may need to bleed a pint or so of fluid off
to get all the air out. If the air is close to the master cylinder it will
have to be pushed all the way out of the wheel cylinders.
I think the problem is really in the right rear with no bleeder,
probably was twisted off at one time. In that case you should probably just
replace the wheel cylinder and save yourself a lot of grief.


<cselby DeleteThis @mts.net> wrote in message news:477f2966.78274718@news.mts.net...
> I've been a licenced mechanic since 1971 and I am since retired and
> have forgotten something obvious about brakes.
>
> My kids Mazda MPV 4WD with rear wheel "ABS" has a low brake pedal. I
> took the master cyl off and stripped it down, washed it out, rubbers
> looked good, cylinder clean and smooth, re-assembled and began to
> bleed the brake system. I got no improvement in the brake pedal -
> still way too low.
>
> Rear drums removed, shoes & hydraulics inspected, brakes adjusted
> manually to "just" rubbing. Front pads will need replacement
> sometime this summer, but still serviceable. No leaks in any of the
> cylinders or calipers. Rear brakes bleed on the left side only - the
> right side has no bleeder, but another line going to the left side
> which has the bleeder. There is a bleeder on the "ABS" module that
> feeds both rear brake cyls.
>
> I must be missing something really obvious, and I can't for the world
> of me think what. Before I go and strip everything down to nothing,
> I need someone with the "obvious" answer.
>
> Thanks
>
> Pete