Huge IBM 1800 find (and need some help)

Jon Elson elson at
Sat Mar 21 14:50:14 CDT 2015

OK, a quick search shows the 2311 was indeed hydraulic!  
(The following comes from my knowledge of the 2314, but it 
is likely to be similar.)  These had a Cessna hydraulic pump 
belt-driven by the same belt that turned the spindle.  Short 
hoses connected it to a big tank at the back.  This acted as 
the fluid reservoir as well a a housing for the servo valve 
and the linear actuator.  It is very likely the seals on the 
pump, valve and actuator have deteriorated, and the hoses 
are cracked and brittle.  If you were to fire it up, the 
hoses might blow, and spray oil all over the inside of the 
drive.  This has happened at the two installations I was at, 
while under IBM maintenance in the early 1970's.  It caused 
a lot of damage.


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