721D - Hydro Whine/Scream

[ensminger]

Went to look at a GH 721D I found on Craigslist yesterday. It's a 92 with 870 hours on the meter, the guy wants $3000. Looks like a nice mower, but whenever the hydros are activated - whenever you are going forward, backward, turning left or right, OR when you push the bars out a *little* too far - the hydros scream like a witch burning in oil. Before I left, the guy took the mower behind his house to park in his garage, and I could hear them scream still when I was on the other side of the house. He said the unit was just serviced by a reputable shop in the area (it was an hour away from me, so I'm not familiar with the shop).

Anyone have any experience with this scenario in particular? Any idea how much those hydro units go for (I've heard from $600 - $1200)? Seems to me like I should expect to replace both hydros. Some research I did on this site sounds like I might be able to get by with replacing some seals and such internally in the hydros - but I think in cases like this I should expect to replace both and be pleasantly surprised otherwise.

Thanks guys for your thoughts

 

[MBDiagMan]

It's hard to know much without hearing it myself, but the first thing to check is the belts.

 

[ensminger]

I'll follow up here for the sake of the thread - I talked to my local mower repair shop, with whom my family's come to trust over the past several years. He said that the old Gemini hydros (common on older Grasshoppers) are known to whine like that. Even shortly after new, they will squeal. His thinking was that they are probably fine, unless they are leaking, which these weren't. I bought the mower, so i"ll let y'all know if it gives me fits.

Thanks for the reply.

 

[Jinzo Ningen]

My 1997 721D also has Gemini motors and they are extremely quiet, I think. Then again, I've never heard a non-Gemini equipped GH running so maybe I'm just used to the noise?