Scagg Tiger cup hydraulic issues

[Jesse Burger]

My Scagg STC48A-20CV the left wheel motor stopped during operation and oil started pumping out from my reservoir. I decided to drain all the fluid replace the low pressure hoses and rebuild the pumps reassembled everything primed the system the best I could filling the oil filter, filling the pumps when I rebuilt them, replaced the O-rings to the oil reservoir. When I started, the unit with the neutral bypass is open and stroked the pumps forward and reversed twice the wheels were turning slowly the reservoir sucked down 2 1/2 inches then I closed the neutrals and operated again and the left wheel motor stopped first than the right and neither one is working. I was afraid I had air in the system so I tried to purge it pumping fresh fluid from the low pressure inlet side of each pump reassembled same problem still exists. I need some help.

 

[Alan]

That sounds like a frustrating amount of work to put in only to end up right back where you started. Rebuilding both pumps and still having both wheels quit is a rough way to spend a weekend in the garage. Can you tell us a bit more about the mower itself, how long you've had it and what you mainly use it for?

 

[Jesse Burger]

That sounds like a frustrating amount of work to put in only to end up right back where you started. Rebuilding both pumps and still having both wheels quit is a rough way to spend a weekend in the garage. Can you tell us a bit more about the mower itself, how long you've had it and what you mainly use it for?

Yes, I forgot to clarify. It is a tiger cub commercial mower. I bought secondhand with 800 hours on it. The motor was pretty well shot so I replaced it then I noticed my hydraulic controls changing a bit. I had noticed some oil residue on the fill spout of the hydraulic reservoir a couple times. I’m just mowing a 1 acre lot my home with it in South Louisiana. So it’s not gonna see a tunnel use with me hence I figured it was worth replacing a few parts to get it right. Honestly, I don’t think the hydraulic pumps needed to be rebuilt. I think it was. My hoses sucking air, causing the bubbly oil overflow. I considered that may be the wheel motors were bad but I don’t think they would’ve both simultaneously failed after replacing the pumps. I am 100% confident I reassembled the pumps correctly and rerouted all the fresh low pressure hoses correctly. I just don’t know what to do at this point other than bring it to a dealer which I’m not a fan of giving up.

 

[Alan]

800 hours and a fresh motor on it and now this. That's a lot of good work already. Your air-in-the-lines theory actually tracks with the bubbly overflow you saw and it makes sense you'd doubt both wheel motors dying at the same instant.