[AT] 1812 Hydro question

[moscowengnr at yahoo.com]

Steve O.
 
I am not an expert on the Cub hydraulics, but fair on general hydraulics. I have used some Sundstrand pumps before. Some of them have 2 circuits - a high pressure power circuit, and a low pressure "charge" circuit.  If this is a similar system, then a low pressure gear pump pumps oil into the suction of the main high pressure circuit. Because the main "power" pump can reverse, they use check valves to keep the high pressure oil from flowing backward into the "charge" circuit. A check valve with a spring can function as a releif valve with a set pressure the same as the spring setting for that opening area.
Such systems have a charge pump discharge conencted using a tee to both the main pump "A" port and "B" port. Fluid will flow to whichever port is suction at the time. This charge pump flows makes up for small internal leakage in the main pump "power" circuit.
>From reading what I saw in the daily digest postings, this souonds like what you may have.
 
I would question welding or brazing parts together, because there are probably some internal seals.
 
You might try looking at hydraulic supply houses for other check valves.These valves are available in 1/8" though 2" sizes, so you could match the size that you have. You may need to use some adapters of the threads are different types.  Hycon is a brand name that is sold at Womac stores. There are other similar stores on other areas of the country. 
 
I have 7 of the little garden tractor size units myself. One is a hydraulic drive (Case 444) and another is hydrastatic (JD 318). I just got these 2 running this last week. The Case got an overhaul, and the JD got an engine swap. Now I need to finish the accesories on the JD to finish it.
 
Good Luck
Dennis