Simplicity Champion 20/50 SMI - Part # 2690484 (2024)

#7319503/03/16 10:14 PM

Joined: Jun 2015

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Bushy260OP

Good morning all.
My brother-in-law has just picked up a 2005 zero turn Simplicity Champion 20/50 SMI, machine number referenced as Part # 2690484, and it has an issue with the HydroGear drive system.
The machine runs HydroGear HGM-12P-7172 wheel motors on each side with dedicated P Series HydroGear (PE version) 10cc hydrostatic pumps for each motor sharing a single reservoir tank and single oil filter.
I have sourced soft-copies of the mowers Parts Manual, as well as the Service and Repair Manuals for the Wheel Motors and Hydrostatic Pumps.
The mower appears to have less power available on the left motor than it does on the right.
Nephew took it to a friend who tested the machine and said the Wheel Motor was allowing the oil to run straight through, hence the loss of power. I'm a bit suspect of this diagnoses as research indicates failure of a Wheel Motor is uncommon and the issue may be in the Hydrostatic Pump for that side, or even as simple as a loose hose joint.
Have suggested to my brother-in-law that they swap the motors over, or at least the hydraulic lines, and see if the issue follows the motor or stays with the pump.
The other issue that may come into play is the oil that has been used to top up the reservoir as, unlike normal hydraulic systems, this runs using 20W-50 motor oil and if the system was topped up with hydraulic oil, then it needs to be flushed.
These HydroGear Wheel Motors are expensive to replace, so I have suggested that they also try fitting a new Seal Kit, after having the motor cleaned during the process.
It may also pay to install a seal kit to the pump, if that was determined to be in working order.
Any suggestions would be appreciated.
Thank you.

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NormK

Any particular reason as to why you would be suspicious of the wrong oil being added. Any chance of contacting the previous owner for a bit of background info? Swapping the lines over is a good starting point

Last edited by NormK; 03/03/16 10:26 PM.

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Bushy260OP

Thank you for your reply NormK.
My brother-in-law (Greg) advised the nephew (Jason) needed to replace a blown hydraulic line requiring the oil to be topped up. Jason and his mate replaced the line themselves and, as they didn't have the owners manual for the machine, I am suspect on what oil was used and, because they are a family of farmers, I am concerned they may have unknowingly used Hydraulic Fluid rather than 20W-50 motor oil in error.
Greg had used the machine working on the property of the previous owners, so he has a general idea on how it was performing. The machine had the lack of power issue before this line was replaced by Jason, but the previous owners also replaced a blown line before Greg purchased the machine, so there is that little bit of doubt as to oil which could be the cause. Just a passing thought.
I have provided Greg with a hard copy of the Owners Manual, along with a hard copy of the Wheel Motor Service Manual and Parts manual and have just printed off the Pump Service and Repair manual so they can get the machine tested using the actual pressure specifications for the equipment.
According to information I have found, if Hydraulic oil has been used, then it would have contaminated the system and can cause incorrect operation, along with possible damage, to the equipment.
Greg had only asked if I could find a new Wheel Motor for him, but I went further to determine what the possible cause of the issue may be due to the cost of replacement.
The more information I can provide here may help others who come across this issue with their machines as there is a lack of information specific to this on the internet.
Appreciate your feedback.
Thank you.

Last edited by Bushy260; 03/03/16 11:00 PM.

Environmentally friendly recycling at it's best

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NormK

Joined: Jun 2015

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Bushy260OP

Good morning NormK and thank you for your reply.
Jason is working out bush at the moment, so hoping I can get more information over the weekend. I don't think it was the same hose, so hopefully more details will be available once I catch up with him.
I'm not familiar with Hydraulic systems, but from a few bits of information I have read, and a YouTube on Pump & Wheel Motor replacement, it seems hydraulic oil runs the parts too hot and they burn out, but again, I'm not 100% sure about that.

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Bushy260OP

Update: -
Spoke to Greg (brother-in-law) last night and he advise Hydraulic Fluid was put into the system in error when the hydraulic hose was replaced. Last Sunday, they drained as much of the oil out of the system that they could and filled it with 15W-40 (?), not 20W-50 as required, but he said the machine seemed to be going lot better in the short run they gave it. In fact, he now thinks the left side is showing better power than the right. They still need to get the correct oil, but I suggested they run it for a short time, then flush the system and refill with 20W-50 as recommended by manufacturer.
I'll be seeing both Greg and Jason this weekend and will talk about what they have done and give them the Parts Manual for the machine and Service manual for the pumps.
Would appear their Hydraulics Mechanic was not aware of this machine running 20W-50 in lieu of Hydraulic Fluid in the system.
This has just saved them around $1,000 in replacing a LSHT Wheel Motor, plus reducing further damage (and costs) associated with incorrect fluid being used in their HydroGear system.
Making sure the machine is serviced correctly, and that correct fluids are used for the system you have installed, is something everyone should be aware of.
If you don't have your Owners Manual, search and obtain one to give your machine it's best chance of survival and your pockets' best chance of saving money.
Hope this information helps someone else save time and money.

Environmentally friendly recycling at it's best

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NormK

Well done Bushy, glad they got that sorted and didn't cost them a bucket, it is these little tricks that are stumbled on in this forum that can make all the difference. In the words of an old add, "oils ain't oils Sol"