Classic Mustangs List Archive

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Mail From: yahoosubs (Jeff Shanholtz)

I have a '66 coupe. Most of the time when I brake, I get a solid feel for a
second or two. Then the petal gradually sinks to the floor. What seems weird
to me is as it is sinking, if I let go of the petal and immediately press
again, it won't sink anymore... until the next time I need to come to a
stop!

It's pretty consistent; I can't think of any times recently that the problem
hasn't occurred. Weather doesn't seem to matter, nor does brakes being warm
vs. cold.

The only thing I can think to explain it is air in the lines, but why would
the problem go away if I let go of the petal and then press again? I could
replace the fluid if that will solve it, but since I haven't ever drained
all the fluid before I'd rather not figure out how to do it only to find out
after that that's not the problem (hard to find the time when you have 2
little ones!).

Any advice would be appreciated!

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Mail From: cwdaniel (Cliff Daniel)

Sounds like you may have a master cylinder failing. Look for leaks at the
firewall or power booster if so equipped. Otherwise look for leaks at the
wheel cylinders or calipers.
Or
Worn out linings that can't be adjusted any more or just frozen adjusters.

Cliff Daniel
Tempe, AZ

66 Fastback
members.cox.net/cwdaniel/


-----Original Message-----
From: (email redacted)
[mailtoemail redacted)]On Behalf Of Jeff
Shanholtz
Sent: Thursday, August 12, 2004 3:49 PM
To: (email redacted)
Subject: [CM] wierd braking problem


I have a '66 coupe. Most of the time when I brake, I get a solid feel for a
second or two. Then the petal gradually sinks to the floor. What seems weird
to me is as it is sinking, if I let go of the petal and immediately press
again, it won't sink anymore... until the next time I need to come to a
stop!

It's pretty consistent; I can't think of any times recently that the problem
hasn't occurred. Weather doesn't seem to matter, nor does brakes being warm
vs. cold.

The only thing I can think to explain it is air in the lines, but why would
the problem go away if I let go of the petal and then press again? I could
replace the fluid if that will solve it, but since I haven't ever drained
all the fluid before I'd rather not figure out how to do it only to find out
after that that's not the problem (hard to find the time when you have 2
little ones!).

Any advice would be appreciated!

_______________________________________________
Classic-mustangs mailing list
(email redacted)
lists.twistedpair.ca/mailman/listinfo.cgi/classic-mustangs

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Mail From: jinnis (John MacInnis)

Hi Jeff,
It sounds like your master cylinder is bypassing with in the cylinder itself
and yes it can and often not at all times, usually starts at light braking
or while waiting for a traffic light to change. It does not go down in fluid
as it is just going back into the reservoir when this bypassing happens.

Just overhaul it or replace it.
I hope this helps.
John

65 Mustang coupe
66 Mustang coupe

-----Original Message-----
From: (email redacted)
[mailtoemail redacted)]On Behalf Of Jeff
Shanholtz
Sent: Thursday, August 12, 2004 7:49 PM
To: (email redacted)
Subject: [CM] wierd braking problem

I have a '66 coupe. Most of the time when I brake, I get a solid feel for a
second or two. Then the petal gradually sinks to the floor. What seems weird
to me is as it is sinking, if I let go of the petal and immediately press
again, it won't sink anymore... until the next time I need to come to a
stop!

It's pretty consistent; I can't think of any times recently that the problem
hasn't occurred. Weather doesn't seem to matter, nor does brakes being warm
vs. cold.

The only thing I can think to explain it is air in the lines, but why would
the problem go away if I let go of the petal and then press again? I could
replace the fluid if that will solve it, but since I haven't ever drained
all the fluid before I'd rather not figure out how to do it only to find out
after that that's not the problem (hard to find the time when you have 2
little ones!).

Any advice would be appreciated!

_______________________________________________
Classic-mustangs mailing list
(email redacted)
lists.twistedpair.ca/mailman/listinfo.cgi/classic-mustangs

This read-only message was archived from a public mail list.
Mail From: chris (Chris Russell)


FYI, I agree with John's analysis. My first step (after verifying no leaks
anywhere) would be to replace or rebuild the master cylinder. (And do it
soon if you are driving the car!) Chris

At 03:43 AM 8/13/2004, John MacInnis wrote:
>Hi Jeff,
>It sounds like your master cylinder is bypassing with in the cylinder itself
>and yes it can and often not at all times, usually starts at light braking
>or while waiting for a traffic light to change. It does not go down in fluid
>as it is just going back into the reservoir when this bypassing happens.
>
> Just overhaul it or replace it.
>I hope this helps.
>John
>
>65 Mustang coupe
>66 Mustang coupe
>
>-----Original Message-----
>From: (email redacted)
>[mailtoemail redacted)]On Behalf Of Jeff
>Shanholtz
>Sent: Thursday, August 12, 2004 7:49 PM
>To: (email redacted)
>Subject: [CM] wierd braking problem
>
>I have a '66 coupe. Most of the time when I brake, I get a solid feel for a
>second or two. Then the petal gradually sinks to the floor. What seems weird
>to me is as it is sinking, if I let go of the petal and immediately press
>again, it won't sink anymore... until the next time I need to come to a
>stop!
>
>It's pretty consistent; I can't think of any times recently that the problem
>hasn't occurred. Weather doesn't seem to matter, nor does brakes being warm
>vs. cold.
>
>The only thing I can think to explain it is air in the lines, but why would
>the problem go away if I let go of the petal and then press again? I could
>replace the fluid if that will solve it, but since I haven't ever drained
>all the fluid before I'd rather not figure out how to do it only to find out
>after that that's not the problem (hard to find the time when you have 2
>little ones!).
>
>Any advice would be appreciated!
>
>_______________________________________________
>Classic-mustangs mailing list
>(email redacted)
>lists.twistedpair.ca/mailman/listinfo.cgi/classic-mustangs
>
>_______________________________________________
>Classic-mustangs mailing list
>(email redacted)
>lists.twistedpair.ca/mailman/listinfo.cgi/classic-mustangs

--
Chris Russell
Engineering Manager, ZK Celltest Inc.
408-986-8080 x209
(email redacted)

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Mail From: chrisstephens ((email redacted))

I'd replace the master cylinder. My guess is that the O rings on the piston seals better with a little back pressure from the first pump of the pedal. Its just a guess put the part is cheep enough to be worth a try.

Chris


>
> From: "Jeff Shanholtz" <(email redacted)>
> Date: 2004/08/12 Thu PM 10:48:39 GMT
> To: <(email redacted)>
> Subject: [CM] wierd braking problem
>
> I have a '66 coupe. Most of the time when I brake, I get a solid feel for a
> second or two. Then the petal gradually sinks to the floor. What seems weird
> to me is as it is sinking, if I let go of the petal and immediately press
> again, it won't sink anymore... until the next time I need to come to a
> stop!
>
> It's pretty consistent; I can't think of any times recently that the problem
> hasn't occurred. Weather doesn't seem to matter, nor does brakes being warm
> vs. cold.
>
> The only thing I can think to explain it is air in the lines, but why would
> the problem go away if I let go of the petal and then press again? I could
> replace the fluid if that will solve it, but since I haven't ever drained
> all the fluid before I'd rather not figure out how to do it only to find out
> after that that's not the problem (hard to find the time when you have 2
> little ones!).
>
> Any advice would be appreciated!
>
> _______________________________________________
> Classic-mustangs mailing list
> (email redacted)
> lists.twistedpair.ca/mailman/listinfo.cgi/classic-mustangs
>

This read-only message was archived from a public mail list.
Mail From: jeffsubs (Jeff Shanholtz)

Well I finally got my new master cylinder and got it installed last night,
only to discover that the connection to the brake line isn't sealing well.
There was no leak with my old master cylinder, so I'm not sure why this
would be happening. I'm thinking I should replace that little piece of brake
line. Does that sound like the most likely fix for my leak or might the
problem be something else that I haven't thought of?

Thanks guys for your help!

-----Original Message-----
From: (email redacted)
[mailtoemail redacted)] On Behalf Of
(email redacted)
Sent: Saturday, August 14, 2004 7:12 AM
To: A list for owners of Classic Mustangs
Subject: Re: [CM] wierd braking problem

I'd replace the master cylinder. My guess is that the O rings on the piston
seals better with a little back pressure from the first pump of the pedal.
Its just a guess put the part is cheep enough to be worth a try.

Chris


>
> From: "Jeff Shanholtz" <(email redacted)>
> Date: 2004/08/12 Thu PM 10:48:39 GMT
> To: <(email redacted)>
> Subject: [CM] wierd braking problem
>
> I have a '66 coupe. Most of the time when I brake, I get a solid feel
> for a second or two. Then the petal gradually sinks to the floor. What
> seems weird to me is as it is sinking, if I let go of the petal and
> immediately press again, it won't sink anymore... until the next time
> I need to come to a stop!
>
> It's pretty consistent; I can't think of any times recently that the
> problem hasn't occurred. Weather doesn't seem to matter, nor does
> brakes being warm vs. cold.
>
> The only thing I can think to explain it is air in the lines, but why
> would the problem go away if I let go of the petal and then press
> again? I could replace the fluid if that will solve it, but since I
> haven't ever drained all the fluid before I'd rather not figure out
> how to do it only to find out after that that's not the problem (hard
> to find the time when you have 2 little ones!).

This read-only message was archived from a public mail list.
Mail From: rrobaldo (Lance Robaldo)

There could be a bur on the new M.C. preventing a good connection.

Or more likely, the existing brake line has become slightly distorted and no
longer makes a good seal. This is common and happens alot if you've
attached and removed it more than once or twice.

Lance.

----- Original Message -----
From: "Jeff Shanholtz" <(email redacted)>
To: "'A list for owners of Classic Mustangs'"
<(email redacted)>
Sent: Monday, August 23, 2004 1:16 PM
Subject: RE: [CM] wierd braking problem


> Well I finally got my new master cylinder and got it installed last night,
> only to discover that the connection to the brake line isn't sealing well.
> There was no leak with my old master cylinder, so I'm not sure why this
> would be happening. I'm thinking I should replace that little piece of
brake
> line. Does that sound like the most likely fix for my leak or might the
> problem be something else that I haven't thought of?
>
> Thanks guys for your help!
>
> -----Original Message-----
> From: (email redacted)
> [mailtoemail redacted)] On Behalf Of
> (email redacted)
> Sent: Saturday, August 14, 2004 7:12 AM
> To: A list for owners of Classic Mustangs
> Subject: Re: [CM] wierd braking problem
>
> I'd replace the master cylinder. My guess is that the O rings on the
piston
> seals better with a little back pressure from the first pump of the pedal.
> Its just a guess put the part is cheep enough to be worth a try.
>
> Chris
>
>
> >
> > From: "Jeff Shanholtz" <(email redacted)>
> > Date: 2004/08/12 Thu PM 10:48:39 GMT
> > To: <(email redacted)>
> > Subject: [CM] wierd braking problem
> >
> > I have a '66 coupe. Most of the time when I brake, I get a solid feel
> > for a second or two. Then the petal gradually sinks to the floor. What
> > seems weird to me is as it is sinking, if I let go of the petal and
> > immediately press again, it won't sink anymore... until the next time
> > I need to come to a stop!
> >
> > It's pretty consistent; I can't think of any times recently that the
> > problem hasn't occurred. Weather doesn't seem to matter, nor does
> > brakes being warm vs. cold.
> >
> > The only thing I can think to explain it is air in the lines, but why
> > would the problem go away if I let go of the petal and then press
> > again? I could replace the fluid if that will solve it, but since I
> > haven't ever drained all the fluid before I'd rather not figure out
> > how to do it only to find out after that that's not the problem (hard
> > to find the time when you have 2 little ones!).
>
> _______________________________________________
> Classic-mustangs mailing list
> (email redacted)
> lists.twistedpair.ca/mailman/listinfo.cgi/classic-mustangs

This read-only message was archived from a public mail list.
Mail From: w427 (David)

On top of Lance's comments I'd say that if the lines are even the slightest bit out of alignment your chances for leaks are high. Alignment needs to be dead-on with no assistance to center the line in the port and the flare nut starts and runs-on easily with just your fingers.

I just finished another disc conversion last month and once again alignment was the biggest pain. I had 2 weeping leaks, both of which were fixed when I properly aligned the lines, fittings and seats.

HTH,
David

*********** REPLY SEPARATOR ***********

On 8/23/2004 at 10:16 AM Jeff Shanholtz wrote:

>Well I finally got my new master cylinder and got it installed last night,
>only to discover that the connection to the brake line isn't sealing well.
>There was no leak with my old master cylinder, so I'm not sure why this
>would be happening. I'm thinking I should replace that little piece of
>brake
>line. Does that sound like the most likely fix for my leak or might the
>problem be something else that I haven't thought of?

This read-only message was archived from a public mail list.
Mail From: jeffsubs (Jeff Shanholtz)

All you guys are awesome for giving me the advice you did. David, you were
right on the money with the alignment - a couple of slight bends of the
brake line and voila - no leak. And yes, my problem did turn out to be the
master cylinder. Just got back from a test drive and I can't believe how
much better my brakes are now. Not only do they not sink, but they are just
more solid overall.

Thanks!

-----Original Message-----
From: (email redacted)
[mailtoemail redacted)] On Behalf Of David
Sent: Monday, August 23, 2004 11:44 AM
To: A list for owners of Classic Mustangs
Subject: RE: [CM] wierd braking problem

On top of Lance's comments I'd say that if the lines are even the slightest
bit out of alignment your chances for leaks are high. Alignment needs to be
dead-on with no assistance to center the line in the port and the flare nut
starts and runs-on easily with just your fingers.

I just finished another disc conversion last month and once again alignment
was the biggest pain. I had 2 weeping leaks, both of which were fixed when
I properly aligned the lines, fittings and seats.

HTH,
David

*********** REPLY SEPARATOR ***********

On 8/23/2004 at 10:16 AM Jeff Shanholtz wrote:

>Well I finally got my new master cylinder and got it installed last
>night, only to discover that the connection to the brake line isn't sealing
well.
>There was no leak with my old master cylinder, so I'm not sure why this
>would be happening. I'm thinking I should replace that little piece of
>brake line. Does that sound like the most likely fix for my leak or
>might the problem be something else that I haven't thought of?


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