Transmission Case Rear Cover VS hydraulic lift problem

[Gourdeau]

Good morning all.
Based on some replies I received yesterday and in my efforts to find the Hydraulic drain plug I discovered that the very bottom bolt on the Plate Assy, Transmission Case Rear Cover is missing. Although that does not appear to cause a major hydraulic leak, there is nevertheless a small, very small trickle of fluid leaking.
What I am most curious about is, could this missing bolt cause air to get into the system? My hydraulic lift does not maintain it's pressure, allowing the heavy implements such as a rear blade to drop down slowly.
I was about to take the hydraulic control valve unit appart along with the cylinders, BUT, could this missing bolt explain why the hydraulics loose pressure????

Rudi and Ralph, thanks for the earlier replies - very helpful.

[Bigdog]

The missing bolt should have nothing to do with leak down. That is primarily a function of the control valve or the cylinders themselves.

[George Willer]

Gourdeau,

I couldn't imagine the drain plug was like the transmission holes in Johnnie Cash's Cadillac, so I finally went out and looked. The hole is there, but is has a 1/2" pipe connected to it... presumably the supply to the hydraulic pump. It looks like the pipe has a union before connecting to a hose. There's your drain!

[Gourdeau]

George, I think you are correct. I saw that yesterday and thought that if all else failed, loosening that connection would get the Hy. fluid out one way or the other. Thanks a million.
I am just getting ready to fix 2 bolts that hold the Transmission Case Rear Cover to which the 3pth is attached. I discovered that two of the 6 bolt wholes are stipped. It is 3/8" bolts so I went and got metric size bolts and will try resizing the whole just a hair bigger than it's original size. I should not have to drill. Hope it goes well.
Then, draining time!!!!
Thanks a lot -

[Gourdeau]

Well, it's done, the Hy is all out. I also got the control valve unit out, apart and in kerosene. I hope to get the O rings needed to rebuild it. THe kit for this unit is no longer available so I have to improvise.
I also hope that this will solve the hydraulic pressure problem I was having. If not, I will then focus on the 2 cylinders.

Thanks a lot again for the help.

** I don't think that the drain plug was ever taken off. This tractor, a cub Lo-Boy 154 was sitting in a barn for years because of an Estate battle within the previous owner's family. I was a lot of fun trying to get that nut off. I think I come up with a few new choice words today.