[AMC-list] 1981 Spirit 6 cyl air intake trap door vacuum motor failed (more)

[gqrxzy8974@xxxxxxxx]

I decided to try repairing the trap door vacuum motor diaphragm with
Permatex blue RTV (#6BR).   I used this because it seemed to have fewer
fillers (cured it's almost clear, just a light blue) and I had it on
hand.

I first wiped off all surfaces of the diaphragm and inside the tear 
with acetone.  This left black smears on the cloth.  Then after letting
the acetone evaporate for a minute or two I filled the tear and covered
the inside and outside of the diaphragm with Permatex blue RTV (#6BR).

The Silicone RTV went on a bit rough even though I tried to spread it
evenly over the surfaces with the side of a screwdriver.  I tried to
get just a coating over the surface, minimal buildup, still the surface
of the added RTV wasn't all that smooth.  I hung the diaphragm up from
it's metal output ring and let the RTV cure for over 24 hours

The coated diaphragm doesn't look pretty.

This morning I assembled the vacuum motor and tried it with a hand
vacuum source.  This was a quick test so I didn't recrimp the edges.
I tried hand holding it closed but it didn't hold vacuum.  Then I put 3
clamps to hold the edges and that worked.  Without a load the vacuum
motor
pulls in (perhaps 1/2 way) at about 2.5 inches of vacuum and holds 15
inches of vacuum easily (fully pulled in at at lot less vacuum than
that).

PS: Another possible sealant for repairing vacuum motor diaphragms
might be Permatex Black Rubber Sealant.  This is a neoprene rubber,
not a silicone.

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