Replaced hydros in my Toro 724Z this weekend

Discussion in 'Mechanic and Repair' started by Referee, May 27, 2009.

  1. Referee

    Referee LawnSite Member
    Messages: 4

    I just wanted to share my experience from this weekend with the group. For your information, I am not a very good mechanic; as a matter of fact I pretty much hate wrenching although I am mechanically inclined in that I can usually figure things out.

    I have a 1990 Toro 724Z with a 60" deck powered by a 24 horse Onan. I had been having trouble with the one of the Eaton model 7 hydros getting weaker as it got hotter. If I let the mower cool down for about 45 minutes it would seem to work again for a little while. This was only happening with one of the two hydros, so I assumed I had one going bad. Before I decided to purchase new hydros I changed the fluid in the old ones using a 100% synthetic oil. There didn’t seem to be much difference in the way they operated after changing fluids, so I went ahead & ordered 2 new hydros, a 700-022 and a 700-023. The only real difference between the two hydros is the input shaft rotation. They cost $425.00 ea plus $25.00 for combined shipping, ($875.00 total).

    Just in case you are interested I bought them online from a company called Hydraulic Equipment Outlet on eBay at:
    Other places had them priced at $700-$900 each.

    When the hydros arrived I noticed that they were wrapped in heavy plastic & already had oil in them. I assumed they already had the air bled out but I decided to go through the process again just to be on the safe side.

    The biggest time consuming process came in removing the old hydros. It took two of us, (shade tree mechanics) about 5 hours. We were learning as we went. We determined, after we already had the hydros out, that it would be easier to remove the brake drum and drive gear from the output shaft if the hydro was still installed on the machine, so we had to bolt the old hydros back on which wasted about 15-20 minutes. I should mention that you should not put your pulley puller hooks on the brake drums, as you will probably warp them like we did. Instead, try to get the hooks on the sprocket, which is much thicker and durable. As it was, we were able to bend the drums pretty much back into shape with a combination of a hammer and a pry bar but I don’t recommend doing it like that.

    Worth noting, have plenty of penetrating oil on hand. Removing things like the transmission drive couplers from the input shaft, as well as the keys from the keyways, can be very difficult without penetrating oil. Fortunately I had plenty, plus lots of de-greaser, gobs of shop towels and a gallon of hand cleaner, as this was one super messy project. Also note, it is most beneficial to have extra fuel line clamps, cotter pins and/or quick clips on hand. This is even more important if you plan to do a project like this on a holiday, when common and simple parts are not readily available.

    We continued with the installation the next day and spent about 2-1/2 to 3 hours putting it back together. We had incredible success with everything except keeping the keyway keys in place while tapping the press fit parts back onto the hydro’s input and output shafts. My only suggestion is to make sure your mouth is positioned just right otherwise it may never work. Once we figured this mouth thing out, it seemed to work a little better although the neighbors got quite a laugh when they noticed that each key required a different mouth position and that the tough part was determining exactly what that position actually was.

    When we were pretty sure we had it all back together (by noting that we had used all the bolts, nuts, washers, etc.) we stood back and admired our handy work for a minute. I for one wanted to enjoy the moment, hoping that nothing came flying out or off when I started the engine. Then, when I tried to start the mower, it didn’t do anything. I was a little concerned, questioning if maybe we had accidentally knocked a wire off a safety switch or something. So, with my trusty circuit tester light I started tracking the electrical fault. Turns out it was merely a blown fuse. It appears we had touched a hot wire to a ground source. Once the fuse was replace it fired right up. Woo Hoo!

    FYI the input shaft and bearing on the bad hydro pulled out in my hand with just a little pressure from the pry bar while trying to remove the transmission drive coupler and cooling fan. This tells me the hydro was going to completely fail fairly soon anyway, and that I was lucky I replaced it when I did. Also I noticed that the cooling fins on the bottom of both hydros were pretty clogged. I am guessing this was the reason they were overheating to begin with.

    I have a couple questions for the group. How do you keep your hydros clean? The ones I have are located inside the frame and covers as well as being behind the cooling fans, which makes the bottoms difficult to even inspect much less clean. I suppose I could get an inspection mirror, but that won’t give me an easy way to get degreaser to the cooling fins. Another question is have any of you installed piping and shut off valves in place of the drain plug on your hydro so that you can easily drain the fluids for regular oil change maintenance?

    Any input you have would be greatly appreciated.

    Hiawatha, KS
  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029


    You didn't post the unit model number, But.... If I looked at the proper one you should be able to remove the front cover below the seat, This should give you access to the pumps for cleaning. Most likely just a couple times a season ?

    As for a drain valve, Just not sure I'd try that. Maybe a hydro hose shop (NAPA auto parts) could make up extension hoses to put a pipe cap on ?


    Glad you got to do this job instead of me.....
  3. Referee

    Referee LawnSite Member
    Messages: 4

    Sorry about not posting the proper model #. It is:
    1990 Toro 724-Z model # z1-24oe03 (o=oh, 0=zero) with 1047 hrs on it.
    60" Deck model # c5-60zs01

    Oh, thank you very much for the idea about possibly having a hose made. I could probably get that done and have a valve and cap put on it. The only reason I'm considering this is due to the mess created when changing fluids. I considered using standard black pipe w/either a st 90 or a regular 90, depending on clearance, then I noticed that even the plug had a shoulder and gasket. I'm guessing they did this due to the pressure generated in the hydro. This is why I asked. I would rather be safe than sorry.

    While I'm thinking about it, Toro use to make a snow blade for this machine that is no longer available. It is 1988 Snowblade-48 In. # 26-48bz01 If anyone happens to know of one, please let me know. Either that or I'll modify something else to make it work.

    I have used this machine for two seasons now and really like it a lot. The ONLY thing I don't like is my particular deck does not have anti-scalp wheels near the outer edges of the deck. This is another thing that I will end up finding something that should work and modifying it as necessary, then welding it on. If the acreage I mow was flat it would not be a problem as this deck cuts beautifully.

    Anyway, thanks for the reply!

  4. mdapple

    mdapple LawnSite Member
    Messages: 1

    Regarding the oil drain. I just run a 1/4" polyethylene hose through the reservoir top hole all the way to the bottom and withdraw the oil with suction created by a 60cc dairy syringe.
  5. BigFish

    BigFish LawnSite Platinum Member
    Messages: 4,117

    How did ya manage to dig up an over 4 year old thread ??

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