New SCAG Owner

[jeffnang]

I just purchased this mower today and was informed in advance that it may have a pump problem. I test drove it and it worked out good but after I got it home and started moweing, I noticed that it does not want to turn to the left (it kind of feels like a power steering pump low on fluid). It fights you when you try to turn it and it makes a noise.

The guy I purchased it from said he had a new wheel motor put on it last year but it still was acting up so he thought it might be the pump.

Any information would be greatly appreciated.

Jeff

 

[Mad Mackie]

The hydraulic drive system is fairly straightforward. Both pumps have pulleys and are driven by one V belt from the engine. Each pump provides oil under pressure to its respective control valve. The control valve is operated by the respective lever and connecting linkages. The controlled output of the control valve is applied to the wheel motor and the wheel.
On each pump is a dump valve that can be opened so the machine can be moved without it's own power. I would find these valves and make sure that they are both closed as a partially open dump valve will bypass some of the oil internally in the pump and reduce its output.
Other things to look at:
Hyd oil level and quality, should be 20W50 motor oil, but check the operators manual.
Make sure that the pulley on the bad side hasn't sheared or lost its drive key.
Check the control valve linkage and amount of throw and compare it to the good side.
Check the control valve for security.
Check both the pump and wheel motor for security.
Inspect the pump drive V belt.
Inspect the hoses and look for leaks and kinks which can reduce flow.
Replace the hyd oil return filter, bear in mind that when the filter is off the oil in the reservoir will drain out. This is actually the best way to change the oil which is a recommended periodic service.
Let us know what you find.
I need to frequently lubricate the control valves as they get dirty quickly and will hangup some during operation. I blow the dirt off with HP air and then lube them.
Get the model name and number, and serial numbers for your machine and go to the Scag website and download the operators and parts manuals for your specific machine if you don't have manuals. Sometimes the manuals get updated by Scag so check there anyway.
Added note, the deck spindles need a specific type of grease which is different from the general lube for the lube points on the machine.
Mad Mackie in CT:biggrin::laughing:

 

[jeffnang]

Just went down to the barn and checked the valves and they are both shut tight.

Let's say for argument sake that the right side pump is bad (because he told me he changed the right side wheel motor last year). What am I looking at cost wise? And, is this a DIY project?

 

[Mad Mackie]

Get the part number for the pump, both the Scag number and the manufacturers number if you can see it on the pump. You can do a search on line and get some prices, but $400-$600 may be what you are looking at for a pump. You need to clean up the area and have good access to the underside of the machine. The big thing is dripping oil. I have plastic caps and plugs from my aircraft maintenance days that I use to cap off the dripping hydraulic hoses and connections. But no matter what there will be dripping oil!!
Mad Mackie in CT:biggrin::laughing:

 

[jeffnang]

Thanks for the help. Does each pump have a number on it and do I have to take it off to get the number.

 

[Mad Mackie]

No need to remove the pump to get a number, some manufacturers put an aluminum tag on the pumps with the number stamped on it. Get the Scag part number from the parts manual and do an on line search. The pumps are different numbers, left hand and right hand. Wipe the crud off the pump and with a mirror and flashlight look for a part number. The manual that I have for my Tiger Cub shows both the Scag P/N and the manufacturers P/N for the pumps.
Mad Mackie in CT:biggrin::laughing:

 

[jeffnang]

Thanks, I will get that information tomorrow and get back with you on my progress. I really appreciate your help as this is my first zero turn mower.

 

[Mad Mackie]

But make sure that the control valve is working on the side in question and is cycling correctly as you move the lever, of course with the engine not running!!!
Just looking thru my parts manual and I realized that I need to correct my comments about the control valve.
The control valve is integral to the pump and the control lever is attached to a shaft that sticks out of the side of the pump. From this lever the control linkages are connected and go forward to a gas shock and then to the handle or lever that is moved by the operator. The gas shock and it's shaft and spring are what get crudded up and need to be cleaned and relubed periodically.
So jeffnang, I suggest that you make sure that the lever that attaches to the pump control shaft isn't loose on the shaft. There probably is a roll pin that keeps this linkage from rotating on the control shaft which in my parts manual is called a trunnion arm. My Scag is not here right now so I am not able to look directly at it.
Later
Mad Mackie in CT

 

[jeffnang]

Ok, I have an update on my mower. After reading your posts, I decided to take my mower to the local Scag dealer to get their official diagnosis before ordering a new pump. This was a big Mistake because they are jerks and the words customer service waived bye bye to them years ago.

Their offiial dagnsis was my right side pump was bad and "probably" my right side wheel motor was bad and I would be looking at $2,000.00 to fix the mower. Also they advsed me that if I paid more than $50.00 for this mower "you got taken" because "they only made that paticular mower one year and they were the worst ever made").

Well, I brought the mower back home and me and a buddy who has a scagg and does his own repairs took the pump off "in about an hour" and notice that all of the pistons in the "piston pack"
were stuck. Took piston pack to the local parts house and purchased a new one for $56.00.

To make a long story short, replaced the piston pack, reinstalled pump and it's fixed. I have mowed about 15 hours without a hitch.

Thank's for all your help LMF and look forward to more post.

 

[Mad Mackie]

That's great, you lucked out finding a buddy with the expertise!!
Thank you for getting back to LMF with the resolve to your problem.
I need to do a 50 HR service, spindle lube, and blade change on mine today.
Mad Mackie in CT:biggrin::laughing: