Case 646 loader tractor

[Larry Wiebe]

I have a 646-76 Case loader tractor and the problem with it is a sluggish hydrostatic drive. It performs better in low range than high range. I bought this unit from my brother-in law who has since passed on. He had found it in pretty poor shape and got it for a song. It barely drove when he got it. The previous owner apparently used motor oil in the hydrostatic drive. My b-in law flushed it many time with the correct oil and did some other adjustments and got it going. My question to anyone out there is, can the hydrostatic pump be easily rebuilt by replacing the inner parts? Or would it be best to simply buy a new one? The hydraulics on this tractor have plenty of power. It would be great if someone with knowledge of these tractors could share some tips, solutions and wisdom.

Larry Wiebe

 

[Wolfy]

My brother has a several of those Case/Ingersolls. The correct hydraulic drive oil is 15W40 diesel engine oil, as strange as it sounds. Listed in his owner's manual.

 

[Larry Wiebe]

Thanks Wolfy. Hard to think oil type may cause my problem. Can the banana plate or worn hydrostatic pump parts cause the issue?

 

[Xfaxman]

It doesn't have a hydrostatic pump. It is not a hydrostatic system.

It uses motor oil, a hydraulic motor and a hydraulic gerotor pump.

If it has hydraulic fluid in it, it will barely move when the fluid gets warmed up.

Check this Forum: http://www.tractorbynet.com/forums/case-ingersoll/

And a good Website: Case Colt Ingersoll Lawn and Garden Tractor Forum

 

[Larry Wiebe]

Thank you Xfaxman. I will drain and replace the oil as suggested as I'm not sure what's all in there. There is also a lot of play in the fwd/rev lever linkages. Any suggestions on what to start replacing first?

 

[DLTTrekkers]

I once overhauled a hydrostatic box and nothing improofed. The oilpressure reliefvalve operates by pilotpressure and after removing the topcover I found a crack in one pipe .....after brazing that everything was back to normal....I could even spin that tractor in forward and reverse .

 

[Xfaxman]

Thank you Xfaxman. I will drain and replace the oil as suggested as I'm not sure what's all in there. There is also a lot of play in the fwd/rev lever linkages. Any suggestions on what to start replacing first?

Probably from normal wear on the linkage. You might have to make some bushings for it.

 

[Larry Wiebe]

Does anyone know where to find a service manual for the 646 Case?

 

[Xfaxman]

Here: Hydriv.ca