Have a 826 gear drive tractor. I lost steering and brakes. I changed the hydraulic filter, cleaned the screen and still no steering or brakes. I put a gauge in the lube circuit and a gauge in the bottom of the MCV. I had no pressure with the tractor running.The PTO does work. I thought i would have a bad MCV gear or a sheared key. I pulled the MCV and everything looked normal. I inspected the pump- gears were scored along with the housing. I installed a new 12GPM pump and a new gasket kit, o-rings and new springs. I put it all back together, i had lube pressure for a bit then lost it.Tractor steers and i have breaks. I checked pressure on the bottom of the MCV is 210PSI@1000RPM, 225PSI @ 1500 RPM, and 225 at 2000 RPM. Also the T/A will not shift. Still no lube pressure. Any body have this happen or have experience with this issue? Im assuming i have a internal leak somewhere? Thank you