Pump question

[FlyRans]

I'm working on a motor that is similar to a Mercruiser trim pump (J1171 Marine). My pump works but is leaking out of one of the large (21mm wrench) hex nuts at the base. My question is, what seals these? Gasket or o'ring? See pics for detail. I don't want to remove them until I know what I'm getting into. Thanks for any help.

 

[dingbat]

I'm working on a motor that is similar to a Mercruiser trim pump (J1171 Marine). My pump works but is leaking out of one of the large (21mm wrench) hex nuts at the base. My question is, what seals these? Gasket or o'ring? See pics for detail. I don't want to remove them until I know what I'm getting into. Thanks for any help.View attachment 396424View attachment 396423

Could be either.
My guess is an oring, but will not know until you open it up

 

[Scott Danforth]

Look up the oildyne 108 manual (on the parker hydraulic we site)

 

[FlyRans]

Thank you I will look for that on the Parker website.