Hi Gene
I thought the filter was to prevent fuel vapours from entering the pump when
the engine was shut off.
The vacuum in the output side of the pump, and booster, would tend to draw
in fuel vapours from the engine if there was any leakage past the valve in
the pump.
Dave Mumert
- ----- Original Message -----
From: "gene"
To:
Sent: Thursday, July 13, 2000 10:37 PM
Subject: Re: GMC: Rear Disc Brakes-Big Mistake?
> Arch
>
> The way the pumps were installed in the original cars was the carbon
filter
> was placed between the engine and the pump. A lot of the GMC folks buy
the
> filter separate when they buy a new pump.
>
> A carbon pile filter would seem to me to indicate they were trying to keep
> some very reactive gases or oils from some where. Since the filter is on
> the output or pressure side of the pump, the filter would seem to be
> keeping things out of the engine. However it might be there to protect
the
> diaphragm in the pump from the engine gasses during backfires or engine
off
> conditions. The failure mode of these pumps is a hole in the diaphragm so
> this is the weak part of this pump. There are no repair parts for these
> pumps.
>
> Since the original application used the filter in cars in exactly this
> application, most of us are using the filter in the GMC application.
>
> gene
>
> >In a message dated 07/13/2000 9:27:56 PM Central Daylight Time,
> >
> >> The author of the Mustang article might be right with respect to a
> >> Mustang but I wonder if he's ever driven anything as heavy as the GMC?
> >>
> >Emery
> >
> >We may well just have to disagree on this one. Now I am a flat lander
> >so I dont know about them big hills out west but I can lock up my rear
> >wheels at will. That is enough for me. I cant speak to long down hill
runs.
> >Right now I am happy with what I have. Still would like to hear from you
> >on my vacuum pump set up.
> >
> >Take Care
> >Arch 76 GB IL
> >
> Genef -- 77PB/ore/ca
> GMC MOTORHOME INFORMATION
> mr.erf
> http://www.california.com/~eagle/
>
I thought the filter was to prevent fuel vapours from entering the pump when
the engine was shut off.
The vacuum in the output side of the pump, and booster, would tend to draw
in fuel vapours from the engine if there was any leakage past the valve in
the pump.
Dave Mumert
- ----- Original Message -----
From: "gene"
To:
Sent: Thursday, July 13, 2000 10:37 PM
Subject: Re: GMC: Rear Disc Brakes-Big Mistake?
> Arch
>
> The way the pumps were installed in the original cars was the carbon
filter
> was placed between the engine and the pump. A lot of the GMC folks buy
the
> filter separate when they buy a new pump.
>
> A carbon pile filter would seem to me to indicate they were trying to keep
> some very reactive gases or oils from some where. Since the filter is on
> the output or pressure side of the pump, the filter would seem to be
> keeping things out of the engine. However it might be there to protect
the
> diaphragm in the pump from the engine gasses during backfires or engine
off
> conditions. The failure mode of these pumps is a hole in the diaphragm so
> this is the weak part of this pump. There are no repair parts for these
> pumps.
>
> Since the original application used the filter in cars in exactly this
> application, most of us are using the filter in the GMC application.
>
> gene
>
> >In a message dated 07/13/2000 9:27:56 PM Central Daylight Time,
> >
> >> The author of the Mustang article might be right with respect to a
> >> Mustang but I wonder if he's ever driven anything as heavy as the GMC?
> >>
> >Emery
> >
> >We may well just have to disagree on this one. Now I am a flat lander
> >so I dont know about them big hills out west but I can lock up my rear
> >wheels at will. That is enough for me. I cant speak to long down hill
runs.
> >Right now I am happy with what I have. Still would like to hear from you
> >on my vacuum pump set up.
> >
> >Take Care
> >Arch 76 GB IL
> >
> Genef -- 77PB/ore/ca
> GMC MOTORHOME INFORMATION
> mr.erf
> http://www.california.com/~eagle/
>
