Drive repair options for Grasshopper 721

[sgbotsford]

I'm a tree farmer. The aisles between the trees are grassed, and I try to keep a neat appearance by mowing them as needed. This is NOT lawn grade mowing. The turf is ex-pasture, so has alfalfa, vetch, brome, quackgrass, fescue, dandelions, and so on. Pocket gophers are a running battle. So the surface is rough, I mow a fair amount of dirt, and generally abuse the mower.

I bought a used 1995 Grasshopper 721 mower. Paid $4000 (Canadian) Overall I've been quite satisfied with this mower. However it now has 4000 hours on the clock. The right side is starting to get weak. This is especially noticeable when spinning around a tree, or going uphill.

My reading on this site and on others is that the Gemini hydraullic motors are not practical to repair. My dealer says it's $1500 per side to replace. OUCH.

Here's the rub:

The engine is in fine shape. The frame is solid. The mower deck is beat up on the underside. I have to lift it up and pound it straight with a single jack now and then after hitting a rock at full speed.

So: Replacing one side would be worth it.

However: If one side is going, how long before the other side also goes? E.g. If I replace the right side now, am I likely to need to replace the left side next year? Or is this a case that the right side always wears out way before the left because of the preponderance of left turns.

Second idea:

Is there an option to replace the drive system. E.g. replace dual belt drive hydraulic motor/transmissions with a single hydraulic pump and a pair of hydraulic motors?

Or should I bite the bullet and start looking for a new used mower?

[dutch1]

You may want to give Grasshopper a call. There was a time when they were rebuilding the G2 transmissions but have ceased doing so. It's possible that they may rebuild the Gemini series, but couldn't confirm without a phonecall.

Don't know what your access to hydro shops but it may be a possibility that someone may be able to rebuild. It's certainly an avenue that I would I would investigate.

To be honest, I doubt frame design would be adaptable to a pump/wheel motor change over.

I checked one source on the pump--$1648----that's a bite.

If rebuildable at a reasonable price, that might be the way to go.

Your mileage may vary.

[one-jene]

A few years ago I had a dealer re-build one for me. The cost at that time was more in the $300 range instead of $1300. It is still working fine for me. It can be tough to find someone with the skills to do the job right.

[sgbotsford]

I emailed Grasshopper via their web page. Got a phone call two hours later. Gentleman talked to me for about half an hour:

* He was interested that it didn't seem to have anything to do with how warm the machine was. He said that problems in the motor usually got worse as the oil warmed up and got less viscous.

* He suggested that I carefully check the linkage between the lever arms and the actuating arm on the motor. If this is out of adjustment, then pushing the arm forward may not fully engage the motor.

* He also suggested checking the check valves in the unit, and gave me some info about that.

BUT he also pointed out that from the serial number it was a 1992 machine, not '95 like I thought, and that 4000 hours was a lot of hours on a mower. He figures that it's likely not worth spending much money on it, as there will be a lot of other worn parts ready to break down fairly soon.

So at this point I'll try to nurse it through the rest of this season, and look at trading it in this fall. Or keeping it as a spare if it is still usable at all.

Anyone got a used 721 in Alberta they want to sell?

[sgbotsford]

Followup: Checked the tire pressure. The right tire was very low. About 2 lbs. Re-inflated tire to proper pressure. Now, no problem. (The right side has always been a bit weak, but I can live with it.)

[dutch1]

sg, that's a simple fix! Surprised you wouldn't have noticed a tire that is down to 2 psi.

If the right side seems weak, you may try adjusting the linkage to equalize--get more length of travel to the control arm. With 4000 hours, you could also have excessive wear in some critical locations.