806, little to no power steering.. I'm lost!

My Farmall 806 has little to no steering assist. It has a wide front end.
It will steer a small amount but it is armstrong steering. Even with the front off the ground it still takes a good amount of force to steer it.
It doesn't steer easier one way compared to the other.
It doesn't help if you raise the RPM's either. The tires will turn a little with the engine off.

The fluid has recently been changed, along with the filter. The 3 point, T/A, and aux hydraulics all work fine, along with the brakes.

Fluid is getting to the steering components up front because recently it started leaking hydraulic fluid by the square plate right below the radiator. We ended up tearing the whole front end out and putting new o-rings on everything. We removed the piston & everything, replacing anything that looked bad. This fixed the leak, but not the steering.

It isn't a priming issue.. We removed the bottom plug on the MCV (facing the step) and started the tractor. Fluid came out quickly but it didn't change the steering at all once reinstalled. We also took out the middle plug, spring, and valve. The orifice on the valve was plugged so we cleaned it out and reinstalled. No change.

I checked the Hydraulic level, even overfilled it by 5 gallons. No change.

We put a gauge on the block right behind the battery on the drivers side.. It read 225-250PSI. Same thing on the bottom port on the MCV.

What else can we check? I need steering!

Thanks in advance.

If this happened after the steering work it is still a prime or air issue if it happened since then after steering was working it is probably the pump. there should be a slice in the lines going to the front by the frame rail opne them up and see if your getting oil there. I use this location as it is easier than at the front under the radiator. they are the same lines just you can slip a hoe on there to catch the oil. There is a plug on the back side of the MCV put a gage on there and see if your getting about 1500PSI at rated engine speed.

With out being there to do some checking myself i am going to throw a couple things at ya to check. as for it being air locked Nah as they are self bleeding. If ya have full T/A function and ya have brakes i am thinking here since you found dirt or what ever it was in the steering orifice and ya have pressure that your flow divider is sticking or that you may have a blowen O/ring or gskt in the MCV. So here ya are going to need a I T manual and set down and read all about the MCV then and only then remove it from the tractor and start taking it apart then with a caliper measure the free length of each spring and check to make sure that all valves float free in there bores . Everything must be kept CLEAN and use NO RAGS to whip off anything . Clean in clean parts washing fluid or diesel and blow dry . Check for any burrs on the valves and lightly polish with vary fine emery . If you are in doubt about the MCV pump change it NOW and do not second guess here as you do not have the means to flow rate it . IF you do not thing you can handle this job then take it to someone that really knows how not someone that THINKS he knows how.

(quoted from post at 11:02:04 07/24/12) With out being there to do some checking myself i am going to throw a couple things at ya to check. as for it being air locked Nah as they are self bleeding. If ya have full T/A function and ya have brakes i am thinking here since you found dirt or what ever it was in the steering orifice and ya have pressure that your flow divider is sticking or that you may have a blowen O/ring or gskt in the MCV. So here ya are going to need a I T manual and set down and read all about the MCV then and only then remove it from the tractor and start taking it apart then with a caliper measure the free length of each spring and check to make sure that all valves float free in there bores . Everything must be kept CLEAN and use NO RAGS to whip off anything . Clean in clean parts washing fluid or diesel and blow dry . Check for any burrs on the valves and lightly polish with vary fine emery . If you are in doubt about the MCV pump change it NOW and do not second guess here as you do not have the means to flow rate it . IF you do not thing you can handle this job then take it to someone that really knows how not someone that THINKS he knows how.

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We checked the MCV pressure on the small port and got 750PSI when dead heading the steering.
So, we pulled the MCV off and disassembled the pump. 2 out of the 3 gaskets were torn, and the final web gasket was stretched somehow.. the holes were elongated.
I will have a new pump tomorrow.... we'll see how it goes.

Myself i would get a seal and Gskt. set and a spring kit and got thru the MCV now while it is off .

(quoted from post at 16:43:58 07/24/12) Myself i would get a seal and Gskt. set and a spring kit and got thru the MCV now while it is off .

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Got one. Will be doing that as well.

The MCV has been all resealed, etc. Nothing was visibly wrong with it.

New hydraulic pump has been installed along with a new drive gear.

Still no change in steering.

We then put a known good used hand pump on it.. no change.

I have removed the valve behind the battery.. It is fed from the mcv and has inlets & outlets to the hand pump and steering up front.

I took off the ends but could not find anything wrong there either...

I am at a loss, what else could it be?

My 706 did the same thing and after checking this and checking that I pulled the plug that is on the bottom of the plate were you pull the horizontal plug to bleed the air out. This plug is vertical and has a spring with a plunger check valve device sorry I'm not a technical term guy. After removing the spring and plunger I cleaned it not that it was dirty put it back together and everything started working. It's worth a try

Finally figured it out! The shuttle valve behind the battery was apparently bad.. It now has effortless power steering.
Apparently the 3rd time is the charm because my shuttle valve appeared ok, the used one I picked up was bad, finally got one off a 706 that did the trick.

I was pretty distraught.. thankfully its finally fixed after screwing around with it for so long.