Open end wrenches should work, flare nut wrench would be better and not as apt to round off the fittings. The system is self bleeding - just cycle it through a few times. If you loose/spill much fluid during the process, be sure to check the fluid level of the transaxle when you are done and top it off with Hy-Tran (the fill plug in the rear end cover). If you are unsure about the condition of the fluid, this would be a good time to change it and the filter, and be sure to use a filter for hydraulic systems and not an oil filter that fits - the two are different internally and an oil filter will cause problems. If you have never changed the fluid on a hydro, you drain it by removing the rear cover, but have a catch pan in place because when the cover is popped loose you will get a flood of hydraulic fluid - 7 quarts worth, all at once. Clean out the inside of any brownish waxy junk, which is actually water that has been absorbed by the Hy-Tran and why I use Hy-Tran, and refill with about 14 pints/ 7 quarts, depending on how much is still in the system, of new fluid.