Husqvarna Z4824 - One weak Hydro

[Clarkbug]

Last year I picked up a Husqvarna Z4824 (Model 968999512) from a coworker to replace an old Toro I had that was starting to really act up. His father had passed away so it was a mower be couldn't use, and only had some idea of the history of it.

It has always been a bit "jumpy" and not the smoothest to operate. I have fixed several issues, like no spacers in the front wheels and one of the caster forks not having a grease zerk to try and assist with the steering. I replaced the ball joints on the end of the control arms, and would add new dampers too, but they are listed as NLA.

I have tried to also adjust the linkage, but on this machine there really is hardly anything that seems to be available at the hydro itself. It seems that the left hydro is getting weaker, as evidenced by trying to drive straight. The left lever can be full forward, but I have to move the right one less to track straight.

Is there anything I can check or adjust on the hydro at this point, or is it a case of run it until it's not usable? I know it's a residential grade mower, but would like to limp it along for a while longer if I can. Makes me almost regret getting rid of the Toro now....

 

[cus_deluxe]

does that have the zt2200 hydro?

 

[Clarkbug]

I'm not sure to be honest. The sticker on it reads HydroGear ZC-DHBB-3D5A-2DPX but I don't know what model that means.....

 

[Shane¹]

Does it get worse when it gets hot? A lot of times it is simple enough to adjust the handle stop screws and where the handles are positioned. Does it go fairly straight backwards?

 

[Clarkbug]

I haven't noticed it getting worse when hot, but will need to pay attention next time I mow. I did adjust the handles and stops last season, and that seemed to help, but I'm happy to try another method if there is something I'm missing. Not sure about backwards. Will need to give that a shot too....

 

[Clarkbug]

So I tried a little moving around yesterday. It is not as bad of a difference between the two sides, but the left side still lags behind the right. So no matter the direction, I need to feather the right handle to keep a straight line. Any ideas what that might mean?

 

[cus_deluxe]

i have a bad boy 54” and im quite sure it has the same hydros that ur mower does and it does the same thing. i think ive heard it said and it makes sense, that the left side usually fails first, since most people tend to blow clippings in, so youre mowing clockwise at least for a few laps, so that over time the left motor wears out sooner. idk. i wouldnt worry much about it.

 

[Clarkbug]

I guess I'm just wondering if it's already acting this way, is it a "run it until you can't drive" it thing? And if so, how much longer do I have. I'm guessing nothing on this unit is serviceable, or at least not for a reasonable amount of money....

 

[cus_deluxe]

i think the newer version of those is “serviceable” but older versions are not.

 

[r7000]

having a honda hrx push mower, and track snowblower, both hydro's...

the hydrostatic transmission(s) (i.e. hydro) has an input pulley that spins at whatever rpm driven by belt coming from the power source (engine). The hydro transmits that energy to the wheel axles to move the vehicle via fluid power - you can look up how a hydro works on youtube with it's two internal piston pumps. the control of output speed on the drive axles is controlled by one lever on the outside of the trans, which is cabled to your go levers. on my mower my cable frayed and lengthened so when I pushed my mower go lever all the way it did not move the lever on the hydro all the way to give me full speed. so u have to get under there and make sure all that levering and cabling is first moving the lever on each hydro to the full forward (and full backward) position. then observe your straight line tracking to see if it's a cable adjustment or one trans is actually weak and not pumping.

a quick look at erplacement parts on husq z4824 shows "HG EZT", which is https://www.hydro-gear.com/

if there is an external friction brake on the hydro then you'll want to check that to see if it's adding resistance.

with "HydroGear ZC-DHBB-3D5A-2DPX" I'd email hydro-gear and ask if they have the tech manual on that model hydro. hydro's go obsolete in 3 months the way new mowers come out, they are as bad as holley/quadrajet carbs.

in general the EZT model (your specific is likely obsolete) are all the same, they are minimal size to fit mowers, run hot because of inadequate cooling, and require oil changes. On "non-serviceable" hydro's they can be serviced if u are mechanically inclined, and just know if the hydro design does not allow for a kind of oil sump (like my hrx mower it's so small) then the unit is completely full of oil and cannot have any air in it and is a b1tch to bleed. if you're hydro is worn inside then you can typically get away with just replacing the pump and motor blocks.

Service & Repair Manuals - Hydro-Gear

Find and download Service & Repair Manuals that contain valuable informationabout your Hydro-Gear Products.

www.hydro-gear.com

 

[r7000]

most hydrogear trans' use 20w-50 motor oil. but verify from the correct service manual for your model. a "hydrostatic transmission 20w50" oil versus whatever 20w50 engine oil off the shelf at walmart is usually better and will give better hydraulic performance. But the internals and operation of a hydro is simple, it doesn't require any complicated lubricating oil. the biggest thing is because of their design and location they run hot so you want a higher viscosity oil.

... so check underneath to remove clumped grass on and around the hydro cooling fan, make sure the drive belt is clean and not slipping, check cables, check hydro oil level and condition and evidence of leakage from axle seals.

 

[Clarkbug]

Thanks for the detailed response. I'll do some digging to see what I can find out and then how much of a pain it is to do any work on the thing....