[AT] OT(?) Cub Cadet 1812 Hydro question

[Steve W.]

Stephen Offiler wrote:
> Hi SteveW:
> 
> Thanks for the inputs; I appreciate it.  Everybody is telling me they
> are PRV's.  It's the shop manual that is calling them "check valves";
> wouldn't they know?  They appear to function as I'd expect a
> check-valve... the spring pressure on the ball is pretty light, so
> it'll flow pretty easily with a small pressure differential in one
> direction, and close up tight going back the other way.  I'd expect a
> PRV to have a much heavier spring, and to hold closed until the
> setpoint is reached.  My problem valve, PRV or not, is located in a
> port on the pump that leads directly to a line to a distribution
> block, and thus appears that they must normally flow in order to
> pressurize that block.  I guess my point is that, while hydraulics are
> NOT one of my specialties, these things do appear to me to be
> check-valves.  I think perhaps the saving grace in the distinction
> between the two types of valves is that this spring is pretty light,
> so I probably have a shot at getting it back together, whereas a heavy
> spring would be a bigger struggle.    And to think...  at first I was
> so pleased to learn how easy it was to access the area, and the
> specific component, that was the root cause of my mystery leak...
> 
> Best regards,
> SteveO.

If they are the ones on top of the hydro they are PRVs for the charge
pump. They are not very strong but they retain some pressure in the pump
to keep it operating without cavitation. They do act as a check valve in
that they don't allow the hydro fluid to return through them.

If you have a lathe and a TIG they can be rebuilt. You need to cut some
of the crimp off then remove the shell. To reinstall the shell you can
do a couple things. One is to TIG a short collar onto the shell and
crimp the shell back on. I have also cut the bottom of the valve enough
that the original shell could just be roll crimped back on.

-- 
Steve Williams