Subject: Re: [Healeys] fuel in Brake Booster

From: Michael <[email-masked]>
Date: Wed, 30 Dec 2015 18:17:45 -0500

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Hi Lindsay,
The air flow direction is normally from the servo to the inlet manifold so =
fuel shouldn't get into the servo BUT if the non return valve on the inlet =
manifold (it is incorporated in the nipple that the servo vacuum hose conne=
cts to) then fuel laden air can, and does, make its way into the servo.
Check that non return valve on the inlet manifold it should prevent any flo=
w towards the servo.

Michael S
BN1 #174=20

-----Original Message-----
From: "R. Price Lindsay" <[email-masked]>
Sent: =E2=80=8E30/=E2=80=8E12/=E2=80=8E2015 6:09 p.m.
To: "Healey List" <[email-masked]>
Subject: [Healeys] fuel in Brake Booster

Listers -=0A=
=0A=
A couple of weeks ago my brakes were acting funny.  It turned out that all =
of the fluid was out of the brake/clutch reservoir.  I sent the brake servo=
 into be repaired at the suggestion of the list.  I just talked to the rebu=
ilder and he said the baffle in the servo was swollen because of a large am=
ount of fuel present in the booster.  He mentioned this is not unusual with=
 TR6=E2=80=9Ds.  I guess this can cause the servo to fail and  draw the bra=
ke fluid into the servo.=0A=
=0A=
Now that the servo is fixed, I don=E2=80=99t want a repeat the problem and =
am searching for a cause for the presence of fuel.  A few months ago I was =
having a problem with fuel starvation.  It turned out to be a pinched fuel =
line.  During my long search I made a number of changes including installin=
g a new distributor cap and wires.  Somehow I switched a couple of wires an=
d could not get a spark in cylinders 5 & 6.  I found the problem after quit=
e a bit of trying to get the car to run smoothly and driving it for 20 - 30=
 miles.  Also, maybe a contributing factor or maybe not, a year or two ago =
I moved the vacuum hose to the induction manifold because I installed air c=
leaners without a connection point for the vacuum hose. (Before the fuel st=
arvation issue I reinstalled the original air cleaners and moved the vacuum=
 hose back up to the air rear cleaner.)=0A=
=0A=
Now for my question: Could the presence of fuel in the brake booster have b=
een caused when I was not getting spark and not burning fuel in 5 & 6?  Cou=
ld the unspent fuel have been sucked into the servo through the induction m=
anifold a while ago, or through the air cleaners recently?=0A=
=0A=
Thank you so much for your collective thoughts.=0A=
=0A=
Price Lindsay=0A=
67 BJ8=0A=
=0A=
=0A=
_______________________________________________=0A=
Archive: http://www.team.net/archive=0A=
=0A=
[email-masked]=0A=
http://autox.team.net/mailman/listinfo/healeys=0A=
=0A=
[email-masked]=0A=
=0A=

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<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html; charset=
=3Dutf-8"></head><body><div><div style=3D"font-family: Calibri,sans-serif; =
font-size: 11pt;">Hi Lindsay,<br>The air flow direction is normally from th=
e servo to the inlet manifold so fuel shouldn't get into the servo BUT if t=
he non return valve on the inlet manifold (it is incorporated in the nipple=
 that the servo vacuum hose connects to) then fuel laden air can, and does,=
 make its way into the servo.<br>Check that non return valve on the inlet m=
anifold it should prevent any flow towards the servo.<br><br>Michael S<br>B=
N1 #174 </div></div><div dir=3D"ltr"><hr><span style=3D"font-family: Calibr=
i,sans-serif; font-size: 11pt; font-weight: bold;">From: </span><span style=
=3D"font-family: Calibri,sans-serif; font-size: 11pt;"><a href=3D"mailto:05=
[email-masked]">R. Price Lindsay</a></span><br><span style=3D"font-family:=
 Calibri,sans-serif; font-size: 11pt; font-weight: bold;">Sent: </span><spa=
n style=3D"font-family: Calibri,sans-serif; font-size: 11pt;">=E2=80=8E30/=
=E2=80=8E12/=E2=80=8E2015 6:09 p.m.</span><br><span style=3D"font-family: C=
alibri,sans-serif; font-size: 11pt; font-weight: bold;">To: </span><span st=
yle=3D"font-family: Calibri,sans-serif; font-size: 11pt;"><a href=3D"mailto=
:[email-masked]">Healey List</a></span><br><span style=3D"font-fami=
ly: Calibri,sans-serif; font-size: 11pt; font-weight: bold;">Subject: </spa=
n><span style=3D"font-family: Calibri,sans-serif; font-size: 11pt;">[Healey=
s] fuel in Brake Booster</span><br><br></div>Listers -<br><br>A couple of w=
eeks ago my brakes were acting funny.&nbsp; It turned out that all of the f=
luid was out of the brake/clutch reservoir.&nbsp; I sent the brake servo in=
to be repaired at the suggestion of the list.&nbsp; I just talked to the re=
builder and he said the baffle in the servo was swollen because of a large =
amount of fuel present in the booster.&nbsp; He mentioned this is not unusu=
al with TR6=E2=80=9Ds.&nbsp; I guess this can cause the servo to fail and&n=
bsp; draw the brake fluid into the servo.<br><br>Now that the servo is fixe=
d, I don=E2=80=99t want a repeat the problem and am searching for a cause f=
or the presence of fuel.&nbsp; A few months ago I was having a problem with=
 fuel starvation.&nbsp; It turned out to be a pinched fuel line.&nbsp; Duri=
ng my long search I made a number of changes including installing a new dis=
tributor cap and wires.&nbsp; Somehow I switched a couple of wires and coul=
d not get a spark in cylinders 5 &amp; 6.&nbsp; I found the problem after q=
uite a bit of trying to get the car to run smoothly and driving it for 20 -=
 30 miles.&nbsp; Also, maybe a contributing factor or maybe not, a year or =
two ago I moved the vacuum hose to the induction manifold because I install=
ed air cleaners without a connection point for the vacuum hose. (Before the=
 fuel starvation issue I reinstalled the original air cleaners and moved th=
e vacuum hose back up to the air rear cleaner.)<br><br>Now for my question:=
 Could the presence of fuel in the brake booster have been caused when I wa=
s not getting spark and not burning fuel in 5 &amp; 6?&nbsp; Could the unsp=
ent fuel have been sucked into the servo through the induction manifold a w=
hile ago, or through the air cleaners recently?<br><br>Thank you so much fo=
r your collective thoughts.<br><br>Price Lindsay<br>67 BJ8<br><br><br>_____=
__________________________________________<br>Support Team.Net http://www.t=
eam.net/donate.html<br>Suggested annual donation&nbsp; $12.75<br>Archive: h=
ttp://www.team.net/archive<br>Forums: http://www.team.net/forums<br><br>Hea=
[email-masked]<br>http://autox.team.net/mailman/listinfo/healeys<br><b=
r>Unsubscribe/Manage: http://autox.team.net/mailman/options/healeys/michael=
[email-masked]<br><br></body></html>=

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---

From: Bob Spidell <[email-masked]>
Date: Wed, 30 Dec 2015 16:58:47 -0800

Price,

I'm having trouble following your description because:

1) there should not be a 'vacuum hose' going into the stock air 
filters.  That is actually a (slight) pressure hose for venting 
crankcase fumes back into the induction system for combustion

2) there IS a vacuum hose from the brake servo--with a check valve at 
the servo or possibly fitted inline in the hose--and it should never be 
installed anywhere but on the nipple on the intake manifold

3) if you want to run a vacuum line from the crankcase to the intake 
manifold you need to install a PCV valve inline

Anyway, the only possible way to get fuel in the servo is from the 
intake system downstream of the carburettors; if 2 cylinders were 
not/mis-firing that unburned fuel would end up in the crankcase and oil 
(and possibly some evaporated back into the induction system). So, yes, 
some fuel could get into the servo via the vacuum line on the manifold, 
but if it was more than a trace your engine would likely be flooded out.

I'm not sure what the servo rebuilder was talking about (unless you 
talked to the tech that did the rebuild he could have been blowing 
smoke).  There is no 'baffle' in the servo; the large air/vacuum piston 
has a rubber/leather seal around the perimeter, and this can get brittle 
contributing to poor operation of the servo.  The typical failure 
mechanism--the one resulting in brake fluid being drawn into the 
air/vacuum cylinder--is the aging and embrittlement of the 'gland seal,' 
a small, circular rubber seal that seals the shaft of the air/vacuum 
piston; on one side is manifold vacuum and on the other is the brake 
fluid in the servo's 'master' cylinder.

If all your hoses, etc. are connected properly to their proper locations 
I would not worry about getting fuel in the rebuilt servo.

Bob

On 12/30/2015 3:07 PM, R. Price Lindsay wrote:
> Listers -
>
> A couple of weeks ago my brakes were acting funny.  It turned out that all of the fluid was out of the brake/clutch reservoir.  I sent the brake servo into be repaired at the suggestion of the list.  I just talked to the rebuilder and he said the baffle in the servo was swollen because of a large amount of fuel present in the booster.  He mentioned this is not unusual with TR6”s.  I guess this can cause the servo to fail and  draw the brake fluid into the servo.
>
> Now that the servo is fixed, I don’t want a repeat the problem and am searching for a cause for the presence of fuel.  A few months ago I was having a problem with fuel starvation.  It turned out to be a pinched fuel line.  During my long search I made a number of changes including installing a new distributor cap and wires.  Somehow I switched a couple of wires and could not get a spark in cylinders 5 & 6.  I found the problem after quite a bit of trying to get the car to run smoothly and driving it for 20 - 30 miles.  Also, maybe a contributing factor or maybe not, a year or two ago I moved the vacuum hose to the induction manifold because I installed air cleaners without a connection point for the vacuum hose. (Before the fuel starvation issue I reinstalled the original air cleaners and moved the vacuum hose back up to the air rear cleaner.)
>
> Now for my question: Could the presence of fuel in the brake booster have been caused when I was not getting spark and not burning fuel in 5 & 6?  Could the unspent fuel have been sucked into the servo through the induction manifold a while ago, or through the air cleaners recently?
>
> Thank you so much for your collective thoughts.
>
> Price Lindsay
> 67 BJ8
>
>
>

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From: Price Lindsay <[email-masked]>
Date: Wed, 30 Dec 2015 20:45:57 -0500

Thanks Bob. I was wrong about the routing of hoses. The repair company is going to give me an in line check valve. Per your note, I should be OK. 

Price Lindsay

Sent from my iPhone

> On Dec 30, 2015, at 7:58 PM, Bob Spidell <[email-masked]> wrote:
> 
> Price,
> 
> 1) there should not be a 'vacuum hose' going into the stock air filters.  That is actually a (slight) pressure hose for venting crankcase fumes back into the induction system for combustion
> 
> 2) there IS a vacuum hose from the brake servo--with a check valve at the servo or possibly fitted inline in the hose--and it should never be installed anywhere but on the nipple on the intake manifold
> 
> 3) if you want to run a vacuum line from the crankcase to the intake manifold you need to install a PCV valve inline
> 
> Anyway, the only possible way to get fuel in the servo is from the intake system downstream of the carburettors; if 2 cylinders were not/mis-firing that unburned fuel would end up in the crankcase and oil (and possibly some evaporated back into the induction system). So, yes, some fuel could get into the servo via the vacuum line on the manifold, but if it was more than a trace your engine would likely be flooded out.
> 
> I'm not sure what the servo rebuilder was talking about (unless you talked to the tech that did the rebuild he could have been blowing smoke).  There is no 'baffle' in the servo; the large air/vacuum piston has a rubber/leather seal around the perimeter, and this can get brittle contributing to poor operation of the servo.  The typical failure mechanism--the one resulting in brake fluid being drawn into the air/vacuum cylinder--is the aging and embrittlement of the 'gland seal,' a small, circular rubber seal that seals the shaft of the air/vacuum piston; on one side is manifold vacuum and on the other is the brake fluid in the servo's 'master' cylinder.
> 
> If all your hoses, etc. are connected properly to their proper locations I would not worry about getting fuel in the rebuilt servo.
> 
> Bob
> 
> 
> 
> Unsubscribe/Manage: http://autox.team.net/mailman/options/healeys/[email-masked]
> 

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