--===============0665898493117972193==
--000000000000331fb405a5018f76
Blowing/sucking into the hose from the intake to the booster will verify if
the one way valve is functioning. That it is all it will tell you. The
described condition is not consistent with a failed one way valve.
A leaky master can leak fluid into the booster. and eventually if the
amount of fluid builds up enough it will get sucked into the engine and
burned.*. Quite often when the master is leaking like this you can see a
trail of brake fluid and dust on the face of the booster directly below the
master cylinder itself.
the other common source for mystery brake fluid disappearances is the rear
wheel cylinders. Between where they are located on the backing plate, and
the dust in the rear brakes it can take a fair amount of leakage before any
is visible. I would suggest if the booster is dry, you pull the rear
drums and examine the wheel cylinders. If there is no obvious leaks, be
sure to peel the boots back and check inside.
hope this helps
Rick
* I had a friend that had a Series 1 E Type. One day he comes out for a
drive and checking under the hood he sees the brake fluid is low. He grabs
a can and starts pouring. All of a sudden the car is billowing acrid white
smoke AND the master reservoir is not getting full. After a couple of
second of Whaaaaaa? He realized that the master had failed and the booster
was full to the vacuum hose port, so everything he poured in was going
right out the exhaust.
On Wed, May 6, 2020 at 12:49 AM PaulHunt73 via Mgs <mgs@autox.team.net>
wrote:
> I'm not aware that blowing and sucking on any tube at the carb will help
> in diagnosing the brakes. If you mean the servo hose that should come from
> the inlet manifold but still be no help.
>
> Stomping on the pedal should not put air into the system, if it does then
> there is a fault somewhere that needs to be found.
>
> Is this single-circuit or dual-circuit brakes? The former should have a
> 'slow-return' valve in the master outlet and with that if a couple of
> quick pumps on the pedal makes the pedal shorter and harder, but then it
> goes long and spongy again if released for a few seconds, that does
> indicate air in the system. Dual circuit varied.
>
> Unless the fluid level in the master dropped right down to outlet level,
> or you have opened the plumbing anywhere, you should not get air in the
> system by being parked up. A leak will of course lower the level, could
> possibly allow air in I suppose, but doubtful in my mind. I've found that
> fluid dropping on a concrete floor 'evaporates' over time. Check the
> carpets under the pedal as that is another place where fluid goes if the
> master secondary seal fails.
>
> Bleeding method varies according to system type i.e. single or dual.
>
> PaulH.
>
> ----- Original Message -----
>
> I have a power assist brake system which after bringing out of winter
> cover my MGB GT V8 exhibited brake failure No brake fluid on the floor but
> it did need topping up. So added Dot 4 but still soft squashy pedal.
> Blowing/sucking on tube to Edelbrock carb (I have a Rover V8 dropped in)
> it sucked but would not blow (I understand this is correct}. So we figured
> that the brakes need bleeding - is this a correct diagnosis? Any tips for
> a non-brake but fairly well versed owner. If I stomped a lot on the pedal
> when engine running would that put air into the brake pipes
>
> _______________________________________________
>
> Mgs@autox.team.net
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--000000000000331fb405a5018f76
Content-Transfer-Encoding: quoted-printable
<div dir=3D"ltr">Blowing/sucking into the hose from the intake to the boost=
er will verify if the=C2=A0one way valve is functioning.=C2=A0 That it is a=
ll it will tell you.=C2=A0 The described condition is not consistent=C2=A0w=
ith a failed one way valve.=C2=A0=C2=A0<div>A leaky master can leak fluid i=
nto the booster. and eventually if the amount of fluid builds up enough it =
will get sucked into the engine and burned.*.=C2=A0 Quite often when the ma=
ster is leaking like this you can see a trail of brake fluid and dust on th=
e face of the booster directly below the master cylinder itself.=C2=A0=C2=
=A0</div><div>the other common source for mystery brake fluid disappearance=
s=C2=A0is the rear wheel cylinders.=C2=A0 Between where they are located on=
the backing plate, and the dust in the rear brakes it can take a fair amou=
nt of leakage before any is visible.=C2=A0 I would suggest=C2=A0 if the boo=
ster is dry, you pull the rear drums and examine the wheel cylinders.=C2=A0=
If there is no obvious leaks, be sure to peel the boots back and check ins=
ide.</div><div><br></div><div><div>hope this helps</div><div>Rick</div></di=
v><div><br></div><div>* I had a friend that had a Series 1 E Type.=C2=A0 On=
e day he comes out for a drive and checking under the hood he sees the brak=
e fluid is low.=C2=A0 He grabs a can and starts pouring.=C2=A0 All of a sud=
den the car is billowing acrid white smoke AND the master reservoir is not =
getting full.=C2=A0 After a couple of second of Whaaaaaa?=C2=A0 He realized=
that the master had failed and the booster was full to the vacuum hose por=
t, so everything he poured in was going right out the exhaust.=C2=A0=C2=A0<=
/div></div><br><div class=3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_a=
ttr">On Wed, May 6, 2020 at 12:49 AM PaulHunt73 via Mgs <<a href=3D"mail=
to:mgs@autox.team.net">mgs@autox.team.net</a>> wrote:<br></div><blockquo=
te class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px =
solid rgb(204,204,204);padding-left:1ex"><u></u>
<div bgcolor=3D"#ffffff">
<div><font size=3D"2">I'm not aware that blowing and sucking on any tub=
e at the carb=20
will help in diagnosing the brakes.=C2=A0 If you mean the servo hose that s=
hould=20
come from the inlet manifold but still be no help.</font></div>
<div><font size=3D"2"></font>=C2=A0</div>
<div><font size=3D"2">Stomping on the pedal should not put air into the sys=
tem, if=20
it does then there is a fault somewhere that needs to be found.</font></div=
>
<div><font size=3D"2"></font>=C2=A0</div>
<div><font size=3D"2">Is this single-circuit or dual-circuit brakes?=C2=A0 =
The=20
former should have a 'slow-return' valve in the master outlet</font=
>=C2=A0<font size=3D"2">and with that if a couple of quick pumps on the ped=
al makes the pedal=20
shorter and harder, but then it goes long and spongy again if released for =
a few=20
seconds, that does indicate air in the system.=C2=A0 Dual circuit=20
varied.</font></div>
<div><font size=3D"2"></font>=C2=A0</div>
<div><font size=3D"2">Unless the fluid level in the master=C2=A0dropped rig=
ht down=20
to outlet level, or you have opened the plumbing anywhere, you should not g=
et=20
air in the system by being parked up.=C2=A0 A leak will of course lower the=
=20
level, could possibly allow air in I suppose, but doubtful in my mind.=C2=
=A0=20
I've found that fluid dropping on a concrete floor 'evaporates'=
over time.=C2=A0=20
Check the carpets under the pedal as that is another place where fluid goes=
if=20
the master secondary seal fails.</font></div>
<div><font size=3D"2"></font>=C2=A0</div>
<div><font size=3D"2">Bleeding method varies according to system type i.e. =
single or=20
dual.</font></div>
<div><font size=3D"2"></font>=C2=A0</div>
<div><font size=3D"2">PaulH.</font></div>
<blockquote style=3D"border-left:2px solid rgb(0,0,0);padding-left:5px;padd=
ing-right:0px;margin-left:5px;margin-right:0px">
<div style=3D"font:10pt arial">----- Original Message ----- </div><font s=
ize=3D"-1"><font face=3D"Arial"><br>I have a power assist brake system whic=
h after=20
bringing out of winter cover my MGB GT V8 exhibited brake failure=C2=A0 N=
o=20
brake fluid on the floor but it did need topping up.=C2=A0=C2=A0 So added=
Dot=20
4 but still soft squashy pedal.=C2=A0=C2=A0=C2=A0 Blowing/sucking=C2=A0 o=
n=20
tube to Edelbrock carb (I have a Rover V8 dropped in) it sucked but would=
not=20
blow (I understand this is correct}.=C2=A0 So we figured that the brakes =
need=20
bleeding - is this a correct diagnosis?=C2=A0 Any tips for a non-brake bu=
t=20
fairly well versed owner.=C2=A0=C2=A0 If I stomped a lot on the pedal whe=
n=20
engine running would that put air into the brake=20
pipes<br></font></font></blockquote></div>
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</blockquote></div>
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