mystery leaking bolt in side of HWH jack cyclinder

[bajasoon]

Hi and Happy New Year!
I've been trying to get a picture / description of what this screwed in bolt / plug is on my HWH jack cylinder to no avail.  It's on the sleeve that the rod goes up into, near the bottom. It looks like it's just a 1/2" bolt, with a washer, into the unit. Is this where one would bleed the system?  Mine is leaking and I can't seem to loosen or tighten it. Hard to get at because of the hanger 'sleeve' , (if that's what it's called), that is right in front of it.
Not sure I'm being too clear here, but  hope someone knows what I mean.  I thought I read somewhere that there might be a 'plugged' hole on single acting jacks that is just not needed ...but used on double acting jacks. And I'm not even sure what 'double acting' jacks are. Mine have 2 springs, but otherwise I don't think they are 'double acting'.
Anyone know what this plug / bolt might be?
Thanks!
Dawn
2004 winnebago journey

 

[bajasoon]

PS  system is 325 HWH jack / leveling system
Thanks, Dawn

 

[Rene T]

Sounds to me like it is a vent plug. he seal has probably failed. It can be a "O" Ring, a white plastic washer or a soft metal gasket. You'll need to remove it and take it to a auto parts store. They should be able to match a gasket for you.

 

[grashley]

A SINGLE ACTING jack (or any cylinder) will use the hydraulic fluid to move the piston in one direction ONLY.  Some other force (gravity) is used to move it in the other direction once hydraulic pressure is released.
A DOUBLE ACTING  jack will use hydraulic pressure and a valve to move the piston BOTH directions.

I'm having a poor recall day.  To me HWH is a hot water heater, but they rarely have hydraulic jacks attached.  I assume this is a leveling system.  Rene is right on with his assessment of a leaking seal.  That may be an unused port for a double acting setup.

 

[Larry N.]

...
I'm having a poor recall day.  To me HWH is a hot water heater, but they rarely have hydraulic jacks attached.  I assume this is a leveling system.  Rene is right on with his assessment of a leaking seal.  That may be an unused port for a double acting setup.

HWH is a brand of levelers, slides and other odds and ends. WH is Water Heater (I wouldn't think Hot was needed). HWH for that heater is confusing to me, and probably others. I even use HWH brand hydraulic oil for the hydraulics on my coach.

 

[grashley]

Thanks, Larry.  HWH sounded familiar, but I could not place it. 
I agree WH is water heater, and HWH is redundant.  Why heat water that is already hot??