This note is a follow-up to a recent posting I made requesting help
for a seized air pump on a TR8. If you don't care about 8s or air
pumps, you can skip this posting....
In my efforts to determine what I could do to repair the air pump, I
went to the Whitlock Autoparts store in Rockford to look through their
reference library of shop manuals. (They have two ten-foot long
magazine rack-type shelves packed with manuals.) In looking through a
1982 Oldsmobile manual, I found an air pump that looked just like the
one that is on my 8. To my dismay, it said that the only servicable
part was the centrifugal filter, which could be pried off of the hub
with an appropriate tool (screwdriver, awl, etc.) Armed with this
advice, I decided to take my chances. I was able to remove the filter
in one piece and found the following information cast into the drive-end
face of the air pump: 7826366 CAV 8 K (The K was upside down in
relation to the previous string of characters.) There was a date grid
that indicated that the unit was manufactured in the 4th week of January
79. On the back plate was cast the following: A 8352
S 7817872
The 8352 was upside-down as compared to the 781782, and the letters AS
were each rotated 90 degrees clockwise from the way I've shown them
here. There was a machined boss on the case of the air pump that had
the number 205192 stamped into it.
When I got the backplate off of the case, I found a cylindrical
housing that held two vanes which rotated around a shaft that was
attached to the backplate. Exposed were the bearings for the vanes, and
the cylindrical housing. These bearings were all free--the seized
bearing was at the drive pulley end. I decided to pull the hub off of
the drive shaft and found a sealed bearing marked NDH MADE IN USA,
after I wiped the dirt away. I sprayed penetrating oil on the seal,
let it sit for a couple of days, and then put a few drops of motor oil
in the same area. The oil must have soaked in and freed the bearing,
as I was able to move the drive shaft and housing somewhat with a large
screwdriver. I applied more oil on the inside of the housing, let it
soak in for a few hours, and tried again. This time I was able to get
a complete revolution, with a few areas that were tighter than others.
I repeated this process several times, and eventually the air pump was
completely freed up. I re-greased the vane and housing-to-backplate
bearings, and reassembled the unit. The shaft was slightly tight, but
after a bit of hand-turning, it felt like a new unit.
Needless to say, I was very surprised at this turn of events. My
luck usually runs in the direction of buying new parts when something
fails unexpectedly. The only misgivings that I have about this repair
are that I was not able to grease the drive end bearing, and the Olds
shop manual that I found specifically warned against oiling the air
pump through the vent holes in the backplate. I was worried about blue
smoke in the exhaust, but that hasn't occurred in the 100 miles that
I've put on the 8 since the repair. I still plan on carrying a sharp
knife in the trunk to cut the belt should the air pump sieze out on the
road somewhere...
Tim Buja Cherry Valley, IL
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