7305 loader hydraulics

sreeb · Aug 8, 2004

I have a "new" used 7305 with the factory 417 loader. I don't yet have any operator or maintenance manuals.

I believe that the loader hydraulics are misconnected some how or there is a problem with the control valve.

Symptoms:

1) It works great when raising the arm or curling the bucket downward. Curling the bucket downward can easily raise the front of the tractor off the wheels.

2) There is little or no power when lowering the arm or curling the bucket upward. There is a whistling noise near the control joy stick and engine sounds loaded. I am guessing this noise is a pressure relief.

There are three hoses connecting the loader controls with tractor. They use quick disconnects. On the tractor side, they are labeled T, P, and N. The hoses are unlabeled. Could these be hooked up wrong?

Otherwise I am assuming there is a problem with control valve itself.

HankStains · Sep 1, 2004

I have the same problem with my Kubota. Although I only have two pipes. Have you had any luck with resolving this yet..

Cheers Pete

sreeb · Sep 4, 2004

I got some info from the Mahindra group and now have the factory manuals.

FWIW:

"T" return from external hydraulics to tank ( float function only) low pressure
"P" supply to external hydraulics, high pressure from pump
"N" return from external hydraulics, from power beyond output of loader spool valve

lever "s" position - use external hydraulics, break something if they are not present
lever "o" position - bypass external hydraulics

I had two problems:

1) The decal on my loader control was wrong and I reversed the bucket curl hoses to make it curl in the "right" direction. I thought you can do this on a double acting cylinder but apparently not. There is something in the spool valve that tries to balance curl/uncurl forces.

2) The arm wouldn't go down because I didn't have full motion of the spool valve. Mine had a detent assembly ( rod with a groove at the end of spool valve piston in a housing with a couple of spring tensioned balls) for going into float mode. The rod had rusted and worn. Rust flakes packed up solid limiting valve travel.