1864 - Hydro trunnion seal leak mimics cork gasket failure

[149Chris]

1864 started dripping hydro fluid. Rushed in to swap cork gasket between hydro and differential that looked OK after disassembly. Put in a new gasket and did a test run before putting fenders, seat, and gas tank back on. Glad I did as the oil was coming from a bad trunnion seal. Repairable but the hydro has to come apart. The oil runs down the differential exactly like a failed cork gasket. The screw driver is pointing to where the oil escapes the hydro.

[CubDieselFan]

Other thread deleted.

I have never replaced that seal, but you already have the rear out so most of the work is done.

[DeltaCub]

The older IH Cub Cadet service manuals have the dimensions to make a jig to support the hydro unit for repair. If you have not taken one of these units apart....read the service manual! Thoroughly clean the outside. Make sure your work bench and tools are clean. Once the valve body is removed, carefully remove the upper rotating group and try to keep that assembly together. There is spirol pin that connects the trunnion arm to the swash plate....DO NOT try to push pin all the way out. Also, note the position of the swash plate....there is thicker and thinner stops casted into the swash plate...it makes a difference if it is installed backwards. Do the repair then inspect everything, use the same hydraulic oil you use in the sump to lubricate the rotating group and swash plate. BTW, when the swash plate is removed take out the spirol pin. Have fun and good luck.

[CubDieselFan]

Originally Posted by DeltaCub

The older IH Cub Cadet service manuals have the dimensions to make a jig to support the hydro unit for repair. If you have not taken one of these units apart....read the service manual! Thoroughly clean the outside. Make sure your work bench and tools are clean. Once the valve body is removed, carefully remove the upper rotating group and try to keep that assembly together. There is spirol pin that connects the trunnion arm to the swash plate....DO NOT try to push pin all the way out. Also, note the position of the swash plate....there is thicker and thinner stops casted into the swash plate...it makes a difference if it is installed backwards. Do the repair then inspect everything, use the same hydraulic oil you use in the sump to lubricate the rotating group and swash plate. BTW, when the swash plate is removed take out the spirol pin. Have fun and good luck.

And that is why she is called the "Queen of the Quit Lines"

[DeltaCub]

Hydro pump jig...very helpful

[TheGrinch]

While it's apart machine the reverse side of the trunnion about .060".

Your reverse will increase to about 1/2 of forward, makes mowing much faster.

Did mine a year ago and never looked back, also check the input shaft for wear at the front needle bearing and replace the shaft if it is sloppy.

[Sam Mac]

Originally Posted by TheGrinch

While it's apart machine the reverse side of the trunnion about .060".

Your reverse will increase to about 1/2 of forward, makes mowing much faster.

Did mine a year ago and never looked back, also check the input shaft for wear at the front needle bearing and replace the shaft if it is sloppy.

This is a great tip. Thanks for sharing this one.

[149Chris]

Made the jig as suggested. Worked great and have it apart. The seal is question is marked CR 6763 (Maybe previously repaired?). The parts list shows a SU-1156097 and may take some chasing to find and is pricy. Any advice on whether to change charge pump O-ring & input shaft seal since it is apart? Probably get the main case gasket for sure. Thanks

[Sam Mac]

Trunnion seals

https://www.google.com/search?client...U-9008000-6701

[Frank1541]

Given the amount of work it takes to get the Hydro out of the tractor and then take it apart, I would replace all the seals. Its cheap insurance.