View Full Version : Scag Zero Turn Hydrolic Problem

10-27-2004, 04:18 PM
I got a hydro-Z for free, i did about 400$ worth of work and everyting seemed to be in line for the past few weeks when i was using it. but now all of a sudden the mower is having a hydrolic issue. both sides feel as though they have no power, and the belt squeaks when trying to go foward and same in reverse but not quite as bad. I dont know where to start but it just seems odd that both would go out at the same time, i dont know how long it sat but that could have been a problem too, the belt seems a little loose, how much tension should be on it? Any insight would be useful, even if it is just an explanation on the mechanics of this system.

10-27-2004, 04:25 PM
oh i also wanted to add, i recently changed the hydro filter, and the fluid with dino 20/50w which is what i called for, should i have used something else????

10-27-2004, 05:25 PM
Check the oil for the hydro unit again (the one you changed) as I recall the oil for one of our skag hydros' was non detergent 30 weight.

10-27-2004, 05:56 PM
It sounds like the belts are to loose to me. You should have a spring to tension it with, get it real tight.
When you changed the fluid did you prime the hydraulic filter? Make sure it has plenty of fluid in it, then start the machine up and let it warm up for a while.


10-27-2004, 07:12 PM
im going to change everything, does anyone know the process to prime and bleed the system?

10-27-2004, 09:46 PM
On the tiger cub, the dealer told me to drain the system and change the filter. Prime the new filter and then fill the hydro tank. Then to jack the rear of mower off the floor to get the weight off the tires. Crank the engine and slowly move the sticks forward to circulate the oil through the system and work the air out. He said to do it like that so as not to put extra strain on the motors and pumps trying to move with the weight of the mower and the operator on the system

10-27-2004, 10:22 PM
I have a Scag Tiger Cub and the manual says to use 20W50 conventional oil. The dealer agrees and I trust him. I fill the filter( Scag) with oil and screw it back on and then fill the reservoir to 3" below the top. I had a problem with hydraulic drive this past summer. The original belt broke and I replaced it. It still wasn't right and had a slight noise. One of the idler pulleys was worn. The bearing had alot of slop. Also Scag had some problems with the tension spring. Check with your dealer for the latest upgrade.... about $15. My spring is on the first hole... the way it came from the factory. The second hole is going to tighten the belt but with everything up to spec it's not needed. The 3rd hole is REAL tight and I would be afraid of putting to much tension on the hydro motors. Hope this helps. Matt

10-27-2004, 10:57 PM
thanks it does, my belt is pretty loose, but it feels like i have some air in the system. i have an old super-z that i use around my house

10-28-2004, 01:48 AM
Some Scag models use 10W30 oil in the hydraulics and others use 20W50. You might want to go to the Scag website < http://www.scag.com > and look up "Scag manuals" on the menu and download the one for your mower. It will give you the right fluid for your machine along with all of the details, specifications, a maintenance and lubrication chart and a troubleshooting guide. The manual will also tell you how to set the tension on your drive belt.

When I change the hydro filter on my eXmark I fill the filter with fresh fluid and after it is installed block the machine up with the drive wheels off the ground and run the machine in drive for a few minutes to purge any air in the system. (Be sure to keep the hydro tank topped-up or you will pump more air into the system.) That has avoided some erratic drive problems I used to get when the hydro filter was changed.


master mower
07-10-2005, 01:41 AM
Here is a stupid question to most of you im sure. I recently bought a used 52" toro hydrostat walk behind. I put tons-o-work into it. It drives fine, but lacks muscle to drive itself onto my trailer!?!? I mean it does get up there, but Im assuming the pumps or drive motors are worn. The mower's hour meter reads 1900 hours. Is this just normal or are the pumps and/or drive motors worn? This is my first hydro walk-behind so I dont know this stuff. Any input would help.

07-10-2005, 03:24 AM
A lot of these units you have to jack up the drive wheels and with the engine at idle move the controls forward and reverse to purge all the air from the system to get the pumps to work right. You may have air it the system. I posted this on here once before, let me see if I can find it again