Stiff hydro control lever

[dgeesaman]

I come here again, hat in hand. Ferris IS 3100z, 800 hrs, 37hp Kawi.

Last year I rebuilt my hydraulic system and had good success except for one pump that had a very slow leak.

In the last month the right side control requires more force to move than before. It seems worst when going slow, but otherwise it's hard to describe more clearly than that. With the mower powered off the linkage moves equally well on both sides.

I was planning to pull that pump and rebuild it again, but I chatted with a guy who suggested I disconnect a line at the wheel motor (wheel lifted obviously) and use the pump to drive out a possible clog in the line.

Anyone else recognize these symptoms and wants to offer a recommendation? Grass is long and growing fast this time of year so I want to get it fixed quickly.

Thanks, David

 

[dgeesaman]

A little update: when I last used it this weekend, the mower had the symptoms i mentioned.

This morning my wife used it for a few minutes and apparently bad things happened. She limped it back to the shed and left a stream of oil drops. The hydro pump seal on the fan side had inverted and blown. I rebuilt the pump and replaced the HP lines, but when I ran the air out of the lines it's clear now the wheel motor is shot because it barely moves.

So now the question is whether to replace the entire wheel motor ($600+), replace both, or rebuild the wheel motor and cross my fingers. (FYI, financially the latter is probably my only sound option).

 

[Dustin4185]

A little update: when I last used it this weekend, the mower had the symptoms i mentioned.

This morning my wife used it for a few minutes and apparently bad things happened. She limped it back to the shed and left a stream of oil drops. The hydro pump seal on the fan side had inverted and blown. I rebuilt the pump and replaced the HP lines, but when I ran the air out of the lines it's clear now the wheel motor is shot because it barely moves.

So now the question is whether to replace the entire wheel motor ($600+), replace both, or rebuild the wheel motor and cross my fingers. (FYI, financially the latter is probably my only sound option).

I would try a rebuild. I have had success with rebuilding a few Hydro Gear wheel motors. I guess it depends on how serviceable it is. What brand wheel motor? My dad had a Cub Cadet and I found a China made aftermarket at Baileys Hydraulics that fit. It didn't mow as fast, but we got both cheaper than just one side from the dealer. This was on a homeowner machine though.

 

[Lightning Performance]

Pull it apart and check for rubber stuck anywhere in the ports or the main line feed in the valve body control for that motor and the wheel motor ports. I've had hydros get a small rubber piece in the control valve and makes everything in that leg slow. Flow volume is everything in hydros! Get a bucket and compare your flow from on side to the other. Time your test and measure the amount of fluid from each side. Keep the RPM the same for each side when testing flow. Pour back and repeat. Hope that helps.

Oh yea, one last thing, did you clean out your tank? Most have rubber bits floating around in them.

 

[dgeesaman]

Thanks for the info.

Last night I completed my rebuild of the hydro pump and found some light wear / burnishing between the end cap and rotor and the seal on top of the charge pump (under the fan) was blown out. So that's where the oil came from.

After the rebuild I was running the air out of the system and the right wheel would move very slowly if at all. Left side is moving just fine. It made a few intermittent thumping / rattling sounds or vibrations coming from the wheel motor, not just the normal whine of pumping air/oil.

I didn't have time to pull the wheel motor but if I'm a lucky guy there won't be a fragged bearing or anything.

I stopped at Messick's again today and this time I have a wheel motor rebuild kit and new hydraulic filter.

I will clean out the reservoir. I did not see any loose material in there (there was no obvious source found when I rebuilt the pump) but now I'm not so sure.

 

[dgeesaman]

Final wrap-up:
I tore down the wheel motor and found nothing wrong with it. Put it back together.
The hydro pump lower seal blew out. What a mess that makes! The leak soiled both belts with oil, oil everywhere. At least there will be less rust down there for a while.

Also found all of the rotor piston springs twisted up and destroyed. I assume that's because I made an error assembling it. My best theory now for the initial issue is one of the check valves or relief valves was not working quite right, leading to overpressure inside the pump.

Ordered a new pump from Pats Small Engine Parts - fingers crossed, it's like new. Once the sun dries out the grass there will be lots of mowing to do today and tomorrow.