Help with Grasshopper Hydraulics

[Luffydog]

Doesn't look to be hydro gear pump from the pic. Also look the see if there is a snap that holds it in. That might be the input shaft. Hard to tell from the pic.

[Fulltilt]

Doesn't look to be hydro gear pump from the pic. Also look the see if there is a snap that holds it in. That might be the input shaft. Hard to tell from the pic.

Its not.
It's an Eaton/Gemini Transaxle assy.

It is
What else could it be?

[Fulltilt]

I thinking it is the Eaton 771.

Can you Verify if it is the Eaton 771? If so I can send you the service manual.

It is/ should be the Eaton/Gemini 771 series.

[Fulltilt]

Here ya go RMR : http://www.eaton.com/ecm/groups/public/@pub/@eaton/@hyd/documents/content/pll_1620.pdf
And this : http://www.vickershydraulic.com/site/pdfs/06-428.pdf Very good parts illustration.

[Luffydog]

Year-1991= the right side pt# 391211 left side pt# 391210. Year 1997-1999 right side pt# 391213 left side pt# 391212. Found this on the mower shop website.

[RMR]

Thanks for the help guys. There are no numbers on this thing anywhere. But yes it turns out to be a Eaton 771. While you were posting up useful info for me, I went back out to the shop and just dove in. I got the pump rotor off of the oil journal post finally. It turns out my problem lies there as well. The brass clenched bushing has swollen to the point it doesn't have the right tolerance to let it rotate any more. I'm not sure what caused this or even that it was possible for that to happen. I'll call the customer in the morning and give him the good news. Now I'm looking having to buy a used unit on eBay for $600, or sanding it down a .001 at a time til it fits, or hope to find a new bushing at a bearing store and drill all the oil holes by hand. There are pros and cons to all of the options unfortunately.

[KE4AVB]

Probably a case of metal to metal inter-reaction with resulting corrosion pressing the bronze bushing out after it expanded from the heating as this unit has been sitting unused for a few years. If here I would use an adjustable hand reamer if the current diameter was under 1.5 inches to enlarge and true bushing. Got to remember tolerances in hydros are very tight since they are dealing with liquids that thin as they are heated.

The problem would re-occur though as root cause would still be there but if used on a regular base it may just be small amount the would wear away the bronze before it could seize again.

Personally I don't know if you can even get the needed parts from Eaton or one their distributors. I haven't tried finding them before.

[Fulltilt]

Thanks for the help guys. There are no numbers on this thing anywhere. But yes it turns out to be a Eaton 771. While you were posting up useful info for me, I went back out to the shop and just dove in. I got the pump rotor off of the oil journal post finally. It turns out my problem lies there as well. The brass clenched bushing has swollen to the point it doesn't have the right tolerance to let it rotate any more. I'm not sure what caused this or even that it was possible for that to happen. I'll call the customer in the morning and give him the good news. Now I'm looking having to buy a used unit on eBay for $600, or sanding it down a .001 at a time til it fits, or hope to find a new bushing at a bearing store and drill all the oil holes by hand. There are pros and cons to all of the options unfortunately.

The couple I ran across (all on GrassHoppers) indeed had the numbers located where shown in the manuals I linked you to.

I would carry the two parts down to my local automotive machine shop and let them hone it out on their Sunnen ( or similar) hone. They can fit it to whatever tolerance you require, providing they have the correct size hone. Call around.
The problem with an adj. reamer is one chatter mark/grab and your screwed...there goes your close tolerance, no?

You should have read the service manual first...and heeded #49 on page 6. Too late now, right?
Several years ago, when parts were still semi-avail , I made the same mistake, and to be on the safe side, went ahead and ordered a new rotor assy. Nothing wrong with the old one, but...

[KE4AVB]

The problem with an adj. reamer is one chatter mark/grab and your screwed...there goes your close tolerance, no?

That's why you use your head and lightly ream things. Many think you go whole hog when doing it which is a sure way to get chatter plus it easy to over do it. Patience is key.

[Fulltilt]

The problem with an adj. reamer is one chatter mark/grab and your screwed...there goes your close tolerance, no?

That's why you use your head and lightly ream things. Many think you go whole hog when doing it which is a sure way to get chatter plus it easy to over do it. Patience is key.

I know how to properly use a reamer, one of my first jobs was in a truck machine shop, reamed plenty of kingpin bushings, and other stuff. I've line reamed cases/bushings in both small engine and motorcycles over the years.

I'm well versed in the proper use of reamers...that said, I wouldn't use a reamer in that particular situation, period.