Subject: Brake failure - Pedal to floor

T

tim jones

New member
Nov 22, 1997
41
0
0
.While in Canada in our 73 GMC had the engine die and lost vacuum to the
brake assist. Felt like the whole brake system quit as I had no brakes at
all. Maybe low vacuum from running low speed in town? As you can tell am
no mechanic.
Tim & Cass Jones
78 Kingsley
Portland, Oregon
84 today, sun and no humidity Subject:

Subject: GMC: Brake failure - Pedal to floor.
|
|
| On my trip to Chi town I got caught in heavy traffic on 90 in the middle
| of Chicago. Lots of slow stop and go and people pulling across 3 to 5
| lanes and always in front of me. Used the pedal alot. On one stop the
| pedal kept going down and no stopping (big brown spot on seat). This
| happened 3 or 4 times and if I pumped some they came up. Brake light
| came on and I could not pull over. Went through a toll booth and got up
| to speed and brakes came back to top. No further problems after that or
| before that.
| Tried 4 panic stops on the way back and everything worked fine with a
| firm solid pedal. Checked fluid and it is clean and full. It was a
| very hot day but brakes were fine before and after.
|
| ANY IDEAS AS TO WHY AND WHAT TO FIX?
|
 
Tim,
Add vacuum pump or vacuum tank with check valves to assist brake vacuum
booster in case of engine shutdown to keep braking assist till stopped for
repair. or have a mighty strong leg pressure.

Ron&Gina
73 Pumpkin-Rose
Ft. Mohave, AZ.

- ----- Original Message -----
From: Tim Jones
To:
Sent: Saturday, July 31, 1999 2:02 PM
Subject: GMC: Subject: Brake failure - Pedal to floor

> .While in Canada in our 73 GMC had the engine die and lost vacuum to the
> brake assist. Felt like the whole brake system quit as I had no brakes at
> all. Maybe low vacuum from running low speed in town? As you can tell am
> no mechanic.
> Tim & Cass Jones
> 78 Kingsley
> Portland, Oregon
> 84 today, sun and no humidity Subject:
>
>
> Subject: GMC: Brake failure - Pedal to floor.
> |
> |
> | On my trip to Chi town I got caught in heavy traffic on 90 in the middle
> | of Chicago. Lots of slow stop and go and people pulling across 3 to 5
> | lanes and always in front of me. Used the pedal alot. On one stop the
> | pedal kept going down and no stopping (big brown spot on seat). This
> | happened 3 or 4 times and if I pumped some they came up. Brake light
> | came on and I could not pull over. Went through a toll booth and got up
> | to speed and brakes came back to top. No further problems after that or
> | before that.
> | Tried 4 panic stops on the way back and everything worked fine with a
> | firm solid pedal. Checked fluid and it is clean and full. It was a
> | very hot day but brakes were fine before and after.
> |
> | ANY IDEAS AS TO WHY AND WHAT TO FIX?
> |
>
>
 
Tim

Leigh Harrison 703-494-9914, Woodbridge, Va has a seperate vac pump avail for
just your situation. Eng quit - flip a switch and the vac pump comes on and
you have breaks again. If you are going to the new 317 pump, it is supposed
to be able to change to a vac pump withe flip of a switch...The big problem is
thinking to flip it when you are trying to avoid hitting something.

Wayne Newland

> .While in Canada in our 73 GMC had the engine die and lost vacuum to the
> brake assist. Felt like the whole brake system quit as I had no brakes at
> all. Maybe low vacuum from running low speed in town? As you can tell am
> no mechanic.
> Tim & Cass Jones
> 78 Kingsley
> Portland, Oregon
> 84 today, sun and no humidity Subject:
>
> Subject: GMC: Brake failure - Pedal to floor.
> |
> |
> | On my trip to Chi town I got caught in heavy traffic on 90 in the middle
> | of Chicago. Lots of slow stop and go and people pulling across 3 to 5
> | lanes and always in front of me. Used the pedal alot. On one stop the
> | pedal kept going down and no stopping (big brown spot on seat). This
> | happened 3 or 4 times and if I pumped some they came up. Brake light
> | came on and I could not pull over. Went through a toll booth and got up
> | to speed and brakes came back to top. No further problems after that or
> | before that.
> | Tried 4 panic stops on the way back and everything worked fine with a
> | firm solid pedal. Checked fluid and it is clean and full. It was a
> | very hot day but brakes were fine before and after.
> |
> | ANY IDEAS AS TO WHY AND WHAT TO FIX?
> |
 
Wayne,

You could turn on the aux. vac pump with a switch in the intake manifold that
senses the loss of vacuum or a switch in the oil line that senses the loss of oil
pressure. Either way, when you lose the engine, the aux vac pump will come
on-line automatically.

Lorry

> Tim
>
> Leigh Harrison 703-494-9914, Woodbridge, Va has a seperate vac pump avail for
> just your situation. Eng quit - flip a switch and the vac pump comes on and
> you have breaks again. If you are going to the new 317 pump, it is supposed
> to be able to change to a vac pump withe flip of a switch...The big problem is
> thinking to flip it when you are trying to avoid hitting something.
>
> Wayne Newland
>
 
The Vac pump (Leigh's) has it's own pressure switch. I think they all do.
I wired mine so that it has a manual "arm" switch. I turn it on when time
would be of the essense to avoid brown stains but in normal cruise it's off.

If on via ignition only (or arm on all the time) it'll come on at engine
start which some might like as it's an indication it's working :-)

another 2 cents thrown in :-)

Heinz

> Wayne,
>
> You could turn on the aux. vac pump with a switch in the intake manifold
that
> senses the loss of vacuum or a switch in the oil line that senses the loss
of oil
> pressure. Either way, when you lose the engine, the aux vac pump will
come
> on-line automatically.
>
> Lorry
>
>
>

>
> > Tim
> >
> > Leigh Harrison 703-494-9914, Woodbridge, Va has a seperate vac pump
avail for
> > just your situation. Eng quit - flip a switch and the vac pump comes on
and
> > you have breaks again. If you are going to the new 317 pump, it is
supposed
> > to be able to change to a vac pump withe flip of a switch...The big
problem is
> > thinking to flip it when you are trying to avoid hitting something.
> >
> > Wayne Newland
> >
>
>
 
Thats why I think the vacuum Tk. is where its at, Vac already stored, Just
got to pick up when you lose the engine. Don't know how many peddles you
might have, But I know you have atleast one good one to stop the lady or
atleast slow it down, to where non assist peddle can bring it to a stop.
Atleast thats what was told to me, Hope I never find out.

Ron&Gina
73 Pumpkin-Rose
Ft. Mohave, AZ.

- ----- Original Message -----
From:
To:
Sent: Saturday, July 31, 1999 9:41 PM
Subject: Re: GMC: Subject: Brake failure - Pedal to floor

> In a message dated 8/1/99 12:14:51 AM Eastern Daylight Time,

>
> I wired mine so that it has a manual "arm" switch. I turn it on when time
> would be of the essense to avoid brown stains but in normal cruise it's
off.
> >>
>
> The only problem with this is that if it takes 10 seconds to pull a vacuum
at
> 60 miles per hour you will have traveled at distance of 1/6 mile or 872
feet
> which is just short of three football fields length. I can see a lot of
> circumstances where it would not save you from a crash.
>
> Emery Stora
> 77 Kingsley
> Santa Fe, NM
 
Hi Emery, No I don't have a vac. pump just a fairly big vac tank 21x7".
Guess I'll have a vac pump after arrival of Thomas but just hooking up as
compressor for now. But I do agree if vac pump only switch should be on.

Ron&Gina
73 Pumpkin-Rose
Ft. Mohave, AZ.

- ----- Original Message -----
From:
To:
Sent: Sunday, August 01, 1999 9:43 AM
Subject: Re: GMC: Subject: Brake failure - Pedal to floor

> In a message dated 8/1/99 12:57:23 AM Eastern Daylight Time,

>
> got to pick up when you lose the engine >>
>
> Ron -- I agree with your use of the manual switch if you have a vacuum
tank,
> however many have put a vacuum pump in line with the booster hose and have
> not installed a vacuum tank. In those cases it seems best to leave the
> vacuum pump powered up all the time. It usually runs only on startup as
long
> as there are no vacuum leaks and the engine is drawing a proper vacuum.
>
> Emery Stora
> 77 Kingsley
> Santa Fe, NM
 
Lorry

Thanks!

Wayne

> Wayne,
>
> You could turn on the aux. vac pump with a switch in the intake manifold that
> senses the loss of vacuum or a switch in the oil line that senses the loss of oil
> pressure. Either way, when you lose the engine, the aux vac pump will come
> on-line automatically.
>
> Lorry
>

>
> > Tim
> >
> > Leigh Harrison 703-494-9914, Woodbridge, Va has a seperate vac pump avail for
> > just your situation. Eng quit - flip a switch and the vac pump comes on and
> > you have breaks again. If you are going to the new 317 pump, it is supposed
> > to be able to change to a vac pump withe flip of a switch...The big problem is
> > thinking to flip it when you are trying to avoid hitting something.
> >
> > Wayne Newland
> >
 
Put in a vacuum pump and it will provide vacuum for the brakes. Gene
fisher's site has the info.
http://www.california.com/~eagle
al

> .While in Canada in our 73 GMC had the engine die and lost vacuum to the
> brake assist. Felt like the whole brake system quit as I had no brakes at
> all. Maybe low vacuum from running low speed in town? As you can tell am
> no mechanic.
> Tim & Cass Jones
> 78 Kingsley
> Portland, Oregon
> 84 today, sun and no humidity Subject:
>
> Subject: GMC: Brake failure - Pedal to floor.
> |
> |
> | On my trip to Chi town I got caught in heavy traffic on 90 in the middle
> | of Chicago. Lots of slow stop and go and people pulling across 3 to 5
> | lanes and always in front of me. Used the pedal alot. On one stop the
> | pedal kept going down and no stopping (big brown spot on seat). This
> | happened 3 or 4 times and if I pumped some they came up. Brake light
> | came on and I could not pull over. Went through a toll booth and got up
> | to speed and brakes came back to top. No further problems after that or
> | before that.
> | Tried 4 panic stops on the way back and everything worked fine with a
> | firm solid pedal. Checked fluid and it is clean and full. It was a
> | very hot day but brakes were fine before and after.
> |
> | ANY IDEAS AS TO WHY AND WHAT TO FIX?
> |
 
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