Old Hydro-Ax 520 with 8' cutter head

Discussion in 'Heavy Equipment & Pavement' started by john_bud, Dec 26, 2007.

  1. john_bud

    john_bud LawnSite Member
    Messages: 32

    Hi, I'm trying to find out information on the old Hydro-ax 520 model with the single spindle rotary cutter.

    Were they reliable units? How does the rotary compare with a mulcher? Also, this one is supposed to have a Detroit Diesel engine 4-53, I think. Never owned one, how reliable are they? Fuel hungry?

    Any info greatly appreciated!

  2. Construct'O

    Construct'O LawnSite Bronze Member
    from Sw Iowa
    Messages: 1,387

    I can't tell you much about the machine,except the engine.The 4-53 would not be my choice as in the Detroit engines.The 4-71 was a lot better engine.I have one in my trencher and has been a great engine,except noisy,but that has nothing to do with performance

    The 4-53 is wet sleve,like John deere 4020,they have rubber o'rings around the sleve and overtime go bad.Then water gets in the oil,the Deere has weepholes in the block that helps, the 4-53 doesn't so no place for the water to go except down which is the oil pan. The 4-71 is dry sleve.

    Unless the machine has a convertor or hydra-static, the Detroit runs out of power quickly,if direct drive.They have to keep there prm's up to have any power.If they are geared right they will run endlessly all day long.

    The are very,very good on fuel.One of the best,especially over all these years,they have out performed all others that i have had for fuel useage.

    They don't like cold weather.Engine heater a must in cold weather.If not heated they take lots of eythel.

    Good luck!:usflag:
  3. bobcat_ron

    bobcat_ron LawnSite Fanatic
    Messages: 10,137

    Is this what you're talking about?

  4. john_bud

    john_bud LawnSite Member
    Messages: 32


    Thanks for the info.

    Bobcat Ron,

    Yep. Looks decent enough for a second gander. Plus it's only an hour away.

  5. janb

    janb LawnSite Senior Member
    Messages: 254

    while I like 4-53's for vintage power (but noisy and economical) .... I think it would be underpowered for such a rig (mobility + cutting). Moving that beast around could be expensive and time consuming for a regular business activity. Depending on your terrain, that unit might be too heavy (marsh land). I've seen the double blade models do some serious, but crude work. Probably for jobs over 1 week (10-20 acres) it might be ok, but not for 5-10 acre places.

    These rotary cutters can do significant clearing, but... finished product is rough and big chunks of stuff left laying around (too big to decompose / work into soil for replanting)

    The mulchers vary in finished product also, so you need to get something applicable to your material and desired results. I do 80 hp rotary cutting, but my results can't compete with 120hp mulchers (nor am I as expensive). For optimal clearing it is tough to do with one machine, but as burning keeps getting more restrictive, cutting needs to be better. I tend to rake the area with my brush forks after mowing and burn, bury or haul off the excess. The guys with 100HP+ can mulch refuse into soils and end up with a seed bed. It seems there are plenty of operators around who can afford to put $100k into mulching machines, I'm not going there; as contractors have filled that void to subsidize their loss of building income, and it is ez to get into serious trouble (falling over cliffs masked by 30' tall blackberries, plus finding hidden wrecked cars and farm equip, steel / pipe fence posts, well casings, cast iron stoves...) This stuff is not exactly good on your $50,000 attachment. I like the results of a 'timber axe' (loftness), counter rotating carbide knives. But not happy digesting rocks and steel, and they don't make a seed bed... generally just a portable mulcher, but great results where practical.
  6. GradeMan

    GradeMan LawnSite Member
    from canada
    Messages: 214

    If buddy wanted 20 to 25 grand I would be all over it, Like a fat kid on a sundae!!!!!!!!!!!:walking: They are not as well liked as a mulcher but people still use them as they are cheaper to operate. Just put the foot to the floor and those sucker throw sticks !!!!!!!!!!

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