Date: Fri, 26 Jul 2013 13:47:49 -0400
Reply-To: David Beierl <dbeierl@ATTGLOBAL.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: David Beierl <dbeierl@ATTGLOBAL.NET>
Subject: Re: Fuel pump noise? Fuel filters.
In-Reply-To: <51eece4f.4461340a.7c77.ffff93b5@mx.google.com>
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Well, I could have done better with this:
At 02:41 PM 7/23/2013, David Beierl wrote:
>As a general description though, from the inlet end there's a fine
>metal screen across the whole diameter of the pump housing leaving a
>little chamber to accumulate crud.
Actually it's plastic, square mesh with about a .005" opening.
> This can be flushed out with
>Brakleen spray from the inlet end. Then the pump itself fills the
>space for part of an inch, and includes the motor bearing on one
>end. It operates something like a vane pump except with little
>rollers to provide the seals instead of vanes. It's sealed to the
>housing by an O-ring, so it takes in on one side and discharges on
>the other, directly into the space occupied by the motor armature and
>magnets (which is most of the overall size). At the far end is a
>plastic cap also sealed with an O-ring. This contains the motor
>brushes, the other motor bearing which is simply four little
>extensions of the plastic, and a check valve built into the base of
>the outlet nipple. This cap is pressed into the aluminum cup which
>forms the rest of the housing and the lip of the cup is crimped around it.
Yes. Well, sorta somewhat. There's an O-ring sealed anodized
aluminum base containing the rather fancy inlet nozzle, an
overpressure relief valve that lets the pump recirculate back to the
inlet if the outlet is plugged, and a 6-mm steel shaft that extends
clear to the plastic cap. What I was calling the bearing in that cap
is simply a locator for this shaft on which all the moving parts turn.
Bolted to the base is a 4-mm thick plate which is the pump body, and
another 4-mm cover plate with a plain punched outlet nozzle. The
rotor and rollers turn inside these. The multiple drive holes in the
rotor that you can see at
http://forums.pelicanparts.com/off-topic-discussions/737082-inside-failed-fuel-pump.html
are filled by a plastic coupler with four prongs on its other
end. They engage a pair of thick prongs on the end of the motor
armature which has a steel sleeve bearing at each end. The armature
is retained on the shaft by a couple thin washers and a circlip.
There, I feel better now.
Yours,
David
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