I just bought a Gravely 160z mower used and was going to change all the fluids before i started using it.. I looked in the books I got with the mower and it said my mower holds almost 4 quarts of Mobile 1 15x50 oil in hydro system. I removed filter as books said and let it drain. When I went to fill it back up it will only hold about 1 and a half quarts. Myy question is is this correct or am I missing or forgetting something. I just dont want to damage the hydro pumps. Any help would great. Thanks
What you did sounds correct, it will hold 4 new, but there is likely quite a bit of residual in there. As long as level shows correct after filling you should be golden.
You "might" have to purge the air out of the hydro system. This is done by raising the drive wheels off the ground and engaging the drive. Keep checking the level of oil. Don't be alarmed if the wheels don't rotate at first. They will start rotating as the air is purged and the oil starts circulating.