806 replaced mcv pump and lost brake pressure?

[anoelke]

Hello everybody
Have a 1966 806 that I use for grinding feed and chores daily on the farm. After changing fluid and filter I Replaced mcv pump due to losing steering constantly. Steering is now great but brakes are barely working. Bled but didn’t find much air. Pedal has much less pressure than before.
Anybody seen this?

Also the shifting linkage is pretty sloppy, where is a good source for components on this? Now it is so loose I can drop the park brake lever down when the tractor is in gear. F and R…

Thanks for all the help this forum has really helped keep this machine working.

Aubrey

 

[Mrfred54]

Did you take the MCV apart and replace all the springs and polish the spools? Replace orings and gaskets? On the brake valve,the feed line coming from the MCV where it connects to the brake valve, there is an office that may be plugged. Your shifting issue, sounds like you will also need to remove the range cover if it’s as sloppy as you say, along with the external parts. This site may have some of the parts you need. Just replacing the pump probably did nothing for your issues. That MCV needs to be gone thru, very throughly

 

[anoelke]

I replaced the pump and the gasket on the plate between the pump and the body of the tractor plus the seals on the shaft of the pump and the O-ring that fits into the body of the tractor, but did not see other seals and not sure what the spools are.

 

[Mrfred54]

There’s another plate that separates from the MCV on the back side and orings and another plate on the outside. The plugs around the MCV all come out and there are spools and springs behind them . Find a hy-capacity dealer in your area and get the MCV gasket and oring kit. And get the spring kit for the spools. You definitely need a service manual. Or find a good IH mechanic in your area. The pressures should also be checked for steering, DD, TA. And lube.

 

[used red MN]

I replaced the pump and the gasket on the plate between the pump and the body of the tractor plus the seals on the shaft of the pump and the O-ring that fits into the body of the tractor, but did not see other seals and not sure what the spools are.

Spools are “spool valves” that slide into bores with passages that direct oil to provide different functions as they move in the bores usually working against internal hydraulic pressure along with spring pressure. Here is the parts break down. CNHI Farmall 806 parts diagram
Here is a video of Pete from “Just a few acres farm” going through one on a 856. Pete’s 856 MCV video The MCV valves on all large frame tractors from the 06 to the 66 series are basically the same.

 

[anoelke]

Spools are “spool valves” that slide into bores with passages that direct oil to provide different functions as they move in the bores usually working against internal hydraulic pressure along with spring pressure. Here is the parts break down. CNHI Farmall 806 parts diagram
Here is a video of Pete from “Just a few acres farm” going through one on a 856. Pete’s 856 MCV video The MCV valves on all large frame tractors from the 06 to the 66 series are basically the same.

 

[anoelke]

The posts/video are really helpful. Same with the diagram. Have the seals but not the springs, will get to work on it tomorrow.
Thank you

 

[Kevin Meier]

Hello everybody
Have a 1966 806 that I use for grinding feed and chores daily on the farm. After changing fluid and filter I Replaced mcv pump due to losing steering constantly. Steering is now great but brakes are barely working. Bled but didn’t find much air. Pedal has much less pressure than before.
Anybody seen this?

Also the shifting linkage is pretty sloppy, where is a good source for components on this? Now it is so loose I can drop the park brake lever down when the tractor is in gear. F and R…

Thanks for all the help this forum has really helped keep this machine working.

Aubrey

Sump check plug come out and not put back in?