Brakes

I have a 71 Dodge Dart that I have been restoring, it has disk brakes.
I have installed a brand new master cylinder on it, the calipers were
old but brand new in box, ran all new brake line and all new bleeders.
I have bled brakes the traditional way, furthest from master cylinder
to closest. I have even used an electric vacuum pump, pumping a pint
of fluid off each wheel not allowing reservoiur to get too low. I can
get pedal but leave my foot off pedal wait ten seconds and pedal goes
clear to floor. Second pump I have some pedal, third pump I have good
pedal. Now I'll mention I can put both feet on this pedal and no fluid
can be seen leaking anywhere, let my foot off the pedal wait ten
seconds and pedal goes clean to floor. How can I possibly be getting
air into this system????? I've bled brakes many times and have never
experienced this.

Big Block wrote:
> I have a 71 Dodge Dart that I have been restoring, it has disk brakes.
> I have installed a brand new master cylinder on it, the calipers were
> old but brand new in box, ran all new brake line and all new bleeders.
> I have bled brakes the traditional way, furthest from master cylinder
> to closest. I have even used an electric vacuum pump, pumping a pint
> of fluid off each wheel not allowing reservoiur to get too low. I can
> get pedal but leave my foot off pedal wait ten seconds and pedal goes
> clear to floor. Second pump I have some pedal, third pump I have good
> pedal. Now I'll mention I can put both feet on this pedal and no fluid
> can be seen leaking anywhere, let my foot off the pedal wait ten
> seconds and pedal goes clean to floor. How can I possibly be getting
> air into this system????? I've bled brakes many times and have never
> experienced this.

Just a thought... did you properly bench-bleed the master?

Toyota MDT in MO

"Big Block" > wrote in
ups.com:

> I have a 71 Dodge Dart that I have been restoring, it has disk brakes.
> I have installed a brand new master cylinder on it, the calipers were
> old but brand new in box, ran all new brake line and all new bleeders.
> I have bled brakes the traditional way, furthest from master cylinder
> to closest. I have even used an electric vacuum pump, pumping a pint
> of fluid off each wheel not allowing reservoiur to get too low. I can
> get pedal but leave my foot off pedal wait ten seconds and pedal goes
> clear to floor. Second pump I have some pedal, third pump I have good
> pedal. Now I'll mention I can put both feet on this pedal and no fluid
> can be seen leaking anywhere, let my foot off the pedal wait ten
> seconds and pedal goes clean to floor. How can I possibly be getting
> air into this system????? I've bled brakes many times and have never
> experienced this.
>

check to be sure the rear brakes are adjusted correctly. loose adj can
give such a symptom. KB

--
ThunderSnake #9 Warn once, shoot twice
460 in the pkup, 460 on the stand for another pkup
and one in the shed for a fun project to yet be decided on

Big Block wrote:

> I have a 71 Dodge Dart that I have been restoring, it has disk brakes.
> I have installed a brand new master cylinder on it, the calipers were
> old but brand new in box, ran all new brake line and all new bleeders.
> I have bled brakes the traditional way, furthest from master cylinder
> to closest. I have even used an electric vacuum pump, pumping a pint
> of fluid off each wheel not allowing reservoiur to get too low. I can
> get pedal but leave my foot off pedal wait ten seconds and pedal goes
> clear to floor. Second pump I have some pedal, third pump I have good
> pedal. Now I'll mention I can put both feet on this pedal and no fluid
> can be seen leaking anywhere, let my foot off the pedal wait ten
> seconds and pedal goes clean to floor. How can I possibly be getting
> air into this system????? I've bled brakes many times and have never
> experienced this.
>


If you ddin't bleed the master cylinder on the bench before putting it
in the car (with rubber tubes looped-back into the reservoir) you'll
never get all the air out. When installed in the car, you can rarely
push the MC piston all the way to the absolute bottom of its travel,
which is necessary. Try pulling the MC back off, bench-bleed it,
re-install, and then re-bleed the brake system;

The other possibility is a bad master cylinder. Brand new ones are
sometimes dead-on-arrival.

On 21 Jun 2005 16:27:16 -0700, "Big Block" > wrote:

>I have a 71 Dodge Dart that I have been restoring, it has disk brakes.
>I have installed a brand new master cylinder on it, the calipers were
>old but brand new in box, ran all new brake line and all new bleeders.
>I have bled brakes the traditional way, furthest from master cylinder
>to closest. I have even used an electric vacuum pump, pumping a pint
>of fluid off each wheel not allowing reservoiur to get too low. I can
>get pedal but leave my foot off pedal wait ten seconds and pedal goes
>clear to floor. Second pump I have some pedal, third pump I have good
>pedal. Now I'll mention I can put both feet on this pedal and no fluid
>can be seen leaking anywhere, let my foot off the pedal wait ten
>seconds and pedal goes clean to floor. How can I possibly be getting
>air into this system????? I've bled brakes many times and have never
>experienced this.


A good troubleshooting procedure with a problem like this is to clamp off
the brakes hoses (3) to isolate the corner with the problem.

You can use vise grips if you cushion the hose with a rag or such or you
can purchase special pliers that are made to clamp off hoses.

Once you have isolated the corner that's causing the problem you will have
a much easier time with the repair.

1. Clamp off both calipers and the rear brakes. If pedal is now high and
firm, release ONE clamp. If pedal is still high and firm, release another
clamp, etc.

If the pedal is still low on first pump with all brakes clamped off then
the master cylinder is the culprit.

--

Dave in Columbus