Test ing a Brake Master Cylinder

I have a 1995 EX Accord which may need a brake master cylinder. I'm
not sure about this because just two weeks ago I had my front rotors
and brakes replaced. Could it be that the mechanic did not bleed the
brakes correctly, and that there is air in the system?

When I press on the brake it goes to its expected place and then
slowly goes down further, until it reaches the floor. This only
happens sometimes, usually at long stop lignts.

Can someone help me out with this.

 

Sounds like your master cylinder to me. Had the same thing happen, with
same behavior as what your seeing.

You should get it fixed right away, the m/c can fail further, without
further warning.

-Arthur

 

Bingo on Master Cylinder. No big deal I got mine from a local Schucks on my
96 Accord EX with ABS for about 80$$$.

What happens is the piston in the master is accustomed to traveling in a
certain range when the pedal is pressed. When the brakes are redone and
bled the pedal is usually pushed to the floor repeatedly to bleed the
brakes. Well debris builds up on the cylinder wall of the master and when
bleeding the piston travels over this previously unused area. This scuffs
up or cuts the seal a bit and this is what causes your leakdown. You will
notice it especially on a downhill stop.

This of course assumes you not leaking fluid anywhere.

It only takes about an hour to do the master with the right tools.

CaptainKrunch

 

Will it help prevent this builddup if we push the pedal all the way to
the floor (maybe by opening one bleed valve) a few times every few
thousand miles?

 

Changing the fluid every 30,000 miles or so is the best thing you can do.
In a car that has had this service neglected for a long time, it's possible
that the damage is already done... changing the fluid might even speed the
death.

 

++++++++++++++++

I think Alan is inferring that the guy who bled your brakes made the
fatal (for your master cylinder / pocketbook) mistake of pushing the
pedal to the floor while bleeding the brakes, which ratched the heck out
of your seal, because it's never been down that part of the bore
before.... What can ya do ? ? ?

Find a better mechanic and get it replaced. OR fight with the existing
guy... :-(

'Curly'

 

||alan wrote:
||> CaptainKrunch wrote:
||>
||>> Bingo on Master Cylinder. No big deal I got mine from a local Schucks
||>> on my
||>> 96 Accord EX with ABS for about 80$$$.
||>>
||>> What happens is the piston in the master is accustomed to traveling in a
||>> certain range when the pedal is pressed. When the brakes are redone and
||>> bled the pedal is usually pushed to the floor repeatedly to bleed the
||>> brakes. Well debris builds up on the cylinder wall of the master and
||>> when
||>> bleeding the piston travels over this previously unused area. This
||>> scuffs
||>> up or cuts the seal a bit and this is what causes your leakdown. You
||>> will
||>> notice it especially on a downhill stop.
||>>
||>
||> Will it help prevent this builddup if we push the pedal all the way to
||> the floor (maybe by opening one bleed valve) a few times every few
||> thousand miles?
||
||
||++++++++++++++++
||
||I think Alan is inferring that the guy who bled your brakes made the
||fatal (for your master cylinder / pocketbook) mistake of pushing the
||pedal to the floor while bleeding the brakes, which ratched the heck out
||of your seal, because it's never been down that part of the bore
||before.... What can ya do ? ? ?
||
||Find a better mechanic and get it replaced. OR fight with the existing
||guy... :-(

Use a shop that uses a vacuum bleeding tool instead of getting the shop boy to
pump the brakes.

Texas Parts Guy