806 Power Steering Question

I have an 806 farmall diesel tractor that i was using this past weekend for blowing snow. Put it away and started it up today and the power steering does not work! There is fluid in the lines, because you can manually steer it. I put it in the shop, jacked up the front and have been messing with it all day, but still does not have PS. The fluid level in the reservoir is at the full mark... it worked fine when we shut it off??

I've never had the problem where I live but some guys on here who live where it gets really cold have found that hydraulic fluid has enough moisture in solution with it that moisture freezes and ice crystals clog the filter. Temps warmed above freezing and problem goes away. Fluid change is called for in this case. New filter and clean bypass screen as shown in Operator's manual.

Will try that... fluid is kinda milky and ugly. Good place to start anyhow... it has been REALLY cold this week too, im sure that doesn't help!

Changing the filter might get the steering working again for a few minutes or hours depending on how much moisture is in the fluid. The oil/water mix forms a gel similar to mayonnaise that stops in the filter. Modern hydraulic systems do require more maintenance than Farmall M hydraulics. Change the hydraulic fluid and filter, then store the tractor in an insulated/conditioned building and work the tractor enough to heat the oil once a month unless you are willing to keep changing the fluid regularly.

Changed fluid and filter today, steering did not get any better... what do we try next?

MCV PUMP IS SHOT ...WHILE YOU GOT THE OIL OUT..CHANGE IT ,

I assume that you cleaned the filter relief valve ( bypass )screen when you changed the filter. Was there junk /slime on it ? It would be typical for moisture laden fluid. When steering first did not work I think that your pump lost prime because of hyd. filter and bypass screen being clogged with ice. You have changed filter and fluid and steering still does not work. Pump most likely still has not primed . Last summer my 756 had noisy and weak steering. I removed filter and found the screen was covered with slime. Cleaned screen and installed with new filter . Started tractor- no steering. I jacked up the front end and took load off the wheels. With engine running, I cycled the steering wheel full limit side to side. Pump took hold of oil and primed and has pumped ever since .
I suggest that you search " 806 Power Steering " ( 856 also )in the Farmall Forum. There are many postings there regarding the same problem you describe. Lots of suggestions for solving them . everything from "let it warm up" to "drive shaft key is broken" to " pump is shot" . I would not go so far now to say that your pump is shot. Try what I did .
Keep us posted.

MCV pump was shot =) had a local repair man put one in and it works like a million bucks, thanks to everyone for your help