Scag Turf Tiger Hydraulic Leak

2002 Scag Turf Tiger with 1900 hours. Hydraulic system just serviced at repair shop (oil and filter). Mower running well for 20 hours. Yesterday while just starting to mow, steering failed and I discovered hydraulic oil on the grass under rear of the mower. There was no oil left in the reservoir. When I tried to loosen the bolt on top of each pump to tow it, I found that each bolt was very tight and could not be loosened by hand, which I have done previously. My husband had to use a wrench to loosen them. Could this have contributed to the hydraulic pump failure? Thanks for the help!

No it is just a valve done up by a shaved monkey who has evolved from the Harley hammer & chisel mechanic to an impact driver mower mechanic.
The problem will have been solely the leak
The question is why did it leak ?

Yes, why did it suddenly dump oil all over the grass. I guess because the mower is 17 years old..? Just repaired an engine oil leak (needed new gasket), now this. Maybe it's time for a new Scag...?

Hi Mowergal,
The dump or bypass valves on the pumps tend to become tighter even having been loosened recently.
Did you have your Turf Tiger serviced at a Scag dealer?
There is the possibility that the hydraulic oil and filter change was not done correctly or the wrong filter was installed.
The hydraulic drive system on your Turf Tiger has two pumps, two wheel motors, a single oil reservoir that supplies oil to the pumps and also receives the return oil from the pumps thru the oil filter.
From each pump there are two high pressure hoses that connect to their respective wheel motors. From the oil reservoir there are low pressure hoses that "tee" into two hoses that connect to the pump suction connections. Similarly there are two low pressure return hoses that "tee" to a single hose and connect to the oil filter. From the oil filter to the oil reservoir there is a single hose for the return oil to the reservoir. Some Turf Tigers have a duplex oil cooler installed in the return system.
So this means that there are many low pressure hose connections that have hose clamps securing them to their respective connections. Hose clamps in time can damage the hose and loosen allowing leakage.
As I do limited servicing on some tractors and mowers, I have had to replace mostly the low pressure hoses and a few high pressure hoses. I have replaced low pressure hoses that have failed from normal deterioration, chaffing and mice damage. :tractor:

Thanks, Mad Mackie. No, not Scag dealer, local small engine repair shop. It does not appear to be a slow leak as most of the oil seems to have dumped almost all at once, I think more to the middle-to-right back. I felt for an oil leak at the hydraulic filter on the left side, I don't think the filter leaked. It is perhaps a coincidence that this is the first hydraulic pump problem I have had in 17 years and just after the shop serviced the hydraulic system, but it may well be due to age. I'm hoping it is just a tube or clamp, and that the pump or pumps were not damaged when all the oil was lost. It's almost as if there was too much pressure in the system, which is why I questioned how tight the bypass valves were. If something was done incorrectly, what are your thoughts as to what that would be?

I tightened them with a wrench after finger tight I put a wrench on them and snug it up. Sounds like you have blown a hydro hose underneath the mower which only takes a couple of seconds to empty it out.

Thanks Luffydog. I got a call from the repair shop that they looked at my mower, will get the details on Tuesday. All I know is the repair "will be expensive," so I guess the pump or pumps were damaged and the whole system will have to be replaced. I will know more after Memorial Day and will update my post.

Dont mean to step on the other guys that are giving you advice, but I think you need to get a 2nd opinion. This shop is either taking you to the bank or dont know anything about the system so they are replacing the thing. I dont know anything about your system but if you give me all the parts and a diagram I can put it together too. I call that a parts changer not a mechanic. Charge for small engine mechanic 65+hr. Charge for parts changer 12$ hr. You dont want someone just throwing parts at it because that will get very expensive quick.

Yes, not sure yet what the extent of repairs will be. From what I have read, the oil leak could have irreparably damaged one or both pumps so I am expecting the worse. I appreciate your comments and will update for everyone's information. FWIW, this mower was completely trouble-free for many years.

Well... I am told that the right hydraulic pump failed or maybe it's the gasket that failed and of course losing the oil damaged that pump. Apparently the right pump going out is a relatively common problem with the system. I am advised that the left pump is okay that there were no pieces of metal in the reservoir or maybe it was in the filter. The repair shop believes the left pump is fine and just to replace the right one which will cost a little under $1,000.
What do you guys think about replacing just one of the pumps when this machine is 17 years old and has 1900 hours? Thanks!