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

Mon Jun 1 09:58:11 PDT 2009

Hi Larry:

According to the parts fiche on the Carter & Gruenewald site (model
1812 garden tractor) this hydro unit has a total of four valves on it.
 Two of them are labelled "Relief Valve" on the fiche and I'd have to
assume those are the dump valves you are referring to.  The OTHER two
valves are called "Check Valves" in the shop manual and just "Valves"
on the fiche, and it is one of THOSE that has failed on my machine.
They are located in a position that appears to output hydraulic
pressure to the spool valve that runs the mower deck lift cylinder

I notice a couple Dump Valves on eBay, and they have little buttons on
top (to manually dump pressure, I suppose).  Mine do not have buttons,
just a tiny vent hole - which is where the leak is coming from.

C&G has them for $141, a slight moderation from the $183 I was quoted
locally.  Part no. is SU-9500085 in case anybody is THAT curious.

Best regards,
Steve O.

On Mon, Jun 1, 2009 at 12:24 PM, Larry Goss <rlgoss at insightbb.com> wrote:
> If I have been following this thread correctly, those are what are called Dump Valves on most hydro units.  Under normal conditions, they don't allow any fluid past them, and only operate so you can move the unit around when the engine is not running.  On some systems, a single valve is all that is needed, but on the Cub Cadets, and others, a valve is needed for both forward and reverse operation.
>
> What's really fun is when one of the valves sticks open after being operated and you only get motion in one direction.  BTDT, thought I was going to go through the back wall of the shop before the valve finally popped back into operation.
>
> Larry
>
>
> Larry
>
>
> ----- Original Message -----
> From: Stephen Offiler <soffiler at gmail.com>
> Date: Monday, June 1, 2009 10:06
> Subject: Re: [AT] OT(?) Cub Cadet 1812 Hydro question
> To: Antique tractor email discussion group <at at lists.antique-tractor.com>
>
>> 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
>> distinctionbetween 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.
>>
>> On Mon, Jun 1, 2009 at 11:11 AM, Steve W.
>> <falcon at telenet.net> wrote:
>> > Stephen Offiler wrote:
>> >> OK, it's not an antique farm tractor, guilty as charged.  It
>> is a 1988
>> >> Cub Cadet (MTD built, a.k.a. "Cub Cadet Corp.") and it is a Model
>> >> 1812, which is built off the same tooling as a real IH Cub
>> Cadet Model
>> >> 782 or so I am told.  I know all about the "IHCubCadet"
>> online forum,
>> >> but nonetheless figured I'd start here on ATIS.  My goal is
>> simply to
>> >> repair this machine so I can make the call whether I want to
>> keep it
>> >> and mow with it, or sell it and buy a modern Zero-Turn-Radius
>> mower.>>
>> >> The basic problem is a leak from the hydraulic system.  It
>> was serious
>> >> enough (say a quart every 15-30 minutes into the cake pan
>> that I was
>> >> forced to rig underneath the machine) that I parked it a
>> couple years
>> >> ago, and here I am today, living proof that occasionally you
>> DO get
>> >> that Round Tuit.
>> >>
>> >> I've got the factory service manual, and it tells me I've got the
>> >> Sundstrand hydrostatic transmission.  With the sheetmetal stripped
>> >> from the steering wheel back, a good power-washing and
>> running off a
>> >> remote battery connected with jumper cables, I found the
>> source of the
>> >> leak, and mercifully it looks like something REALLY simple.
>>  The pump
>> >> has two check valves threaded right into the top, very easy
>> to access
>> >> with no further disassembly.  They are identical, and they
>> each have a
>> >> tiny vent hole centered in the top.  The leak comes from this vent
>> >> hole.  The book says these valves cannot be serviced beyond
>> >> replacement of the o-rings, and removal and inspection of the
>> faulty>> valve shows that it is crimped together and cannot come
>> apart, so I
>> >> agree with the book.
>> >>
>> >> My specific question is this:  if the check valve is leaking
>> out the
>> >> tiny vent-hole in the top, does that mean O-ring replacement,
>> or do I
>> >> need to chase down a whole new valve?
>> >>
>> >>
>> >> Thanks and best regards,
>> >> Steve O.
>> >> _______________________________________________
>> >> AT mailing list
>> >> http://www.antique-tractor.com/mailman/listinfo/at
>> >>
>> >>
>> >
>> > Steve,
>> >  Sorry to be the bearer of bad news but those valves are
>> pressure relief
>> > valves. Not possible to rebuild them. When they leak it means the
>> > internal seal is bad. I have had some luck taking them apart
>> and soaking
>> > them in some cleaner.
>> >
>> > Oh and if you have any other questions try
>> >
>> > http://www.ihregistry.com/
>> >
>> > We welcome ALL of the CC tractors from the originals on up to
>> todays models.
>> > Also have LOT'S of guys with spare parts and new parts as well.
>> >
>> >
>> > --
>> > Steve Williams
>> > _______________________________________________
>> > AT mailing list
>> > http://www.antique-tractor.com/mailman/listinfo/at
>> >
>>
>> _______________________________________________
>> AT mailing list
>> http://www.antique-tractor.com/mailman/listinfo/at
>>
> _______________________________________________
> AT mailing list
> http://www.antique-tractor.com/mailman/listinfo/at
>