Deck Leveling 101A
The easiest way for me to level just about any deck is to use wood 2X4's as a tool, one length of 2X4 on the left side, one for the right side. The 2X4 tools are about 18" long.
Make sure your blades and spindles are true, yes, your deck can get warped in the area of one or more spindles if your blade tips are not matching, and usually requires a sledge hammer to straighten back out (but that is another story). Have a flat concrete floor to work on, make sure all the tires are true also.
Raise deck all the way up
slide tool under left side outer lower lip of deck (2X4 laying flat on the floor)
slide another 2X4 under the right outer lower lip of the deck.
Lower deck until it 'just begins to touch the 2X4 at any point, be it left or right or forward or back', find the closest notch with your lift lever to lock against.
Notice that none of the rollers or deck wheels are touching the blocks of wood.
Look for any bent, twisted, broken or missing linkage components.
Notice which point is touching either of the blocks first, as this is 'the lowest hanging part'.
Notice the difference from left to right, and measure how much. They should be equal
Notice the difference from front to back, and measure the difference. The deck should be lower in the front, than the back. Typically 1/8-1/4" lower in the front. This is the attitude.
Adjust whatever you have to raise or lower the front until the front is lower than the back by 1/8-1/4". If your deck has (2) front trunnion nuts on the front hanger assy., those nuts should be equally measured from the end of the trunnion studs & hanger assy. Adjust both trunnion nuts incrementally, until the deck attitude is where you want it.
Raise the deck up & down till the deck is just touching the blocks, to verify that your attitude is proper. Make sure each trunnion nut is equal to the other by measuring from the end of the studs to the nut.
Then adjust the left & right as necessary, adjust at the deck hanger(s) most decks have one static hanger, and one adjustable hanger.
Raise & lower the deck until both left & right outer lower lip of deck 'just' touches the 2X4 blocks.
Adjust as necessary until both left & right are equal. Yes, you have to get on the floor and look, sometimes it is helpful for a helper to raise the deck while you look when and where it touches first.
Notice if your deck attitude has changed, readjust front trunnions if necessary.
Adjust rollers & deck wheels, depending on how rough your ground is, if very rough ground, then put the wheels in the lowest mounting holes (the wheels will hang down farthest).
But for most lawns, adjust your wheels so they will 'catch' the deck from actually touching the dirt, (usually about 1/2" below the lower deck lip)
The deck wheels are not intended to be running on the ground all the time, they are only for 'catching' the deck in rough areas.
Test.
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