Stewart Vacuum Tank 1920 Super Six

Unknown

Hi, I need some expert advice. On top of the unit there are the connections for the vacuum pump on the dash and the intake manifold.Inside the casting there are two threaded holes one of which had a ball bearing and small grub screw, I assume this is the vacuum check valve. The other hole which corresponds to the dash pump is missing it's ball bearing and grub screw. Looking at the drawing of the Vacuum pump in the service manual - it seems to show that both threaded holes should have a ball bearing and retaining grub screw.

What should these two holes contain ? is it just 2 ball bearings and grub screws ? I'm missing one grub screw which has a odd thread with a diameter of 15/64ths and 22 tpi.



Thanks



Maldwyn Jones in the UK