Hydraulic Problem on X748 with Snowblower

[oldmech]

Hi! I think you have a bad hyd. valve on your blower. They are two Hydrolic systems . Open hyd system and Close hyd. system. If you use one open valve on Close hyd. system you have problem as your. Good luck ! Oldmech

 

[captplaid]

I've ultimately given up. I've screwed the threaded rod and locked the 3pt up.

Personally, I think JD screwed up the engineering on this one. The valve is on the power down for the 3pt. The valve should be on the low pressure side of the cylinder not the high pressure side.

When I'm swnging the spout and this line is on low pressure and the weight of the box lets it free fall. Swing the spount the other way, this line is high pressure and the box goes up with the swing on the front.

I'm not sure why, but tractor hydrualics usually think to restrict the input or high pressure line.

In industry with stationaire hydrualic or air systems, the output, exhuast, or low pressure line (all the same) is where the restrictor is placed and it seems to work much better.

 

[Dutch445]

let's try this, from the JD tech site, here is a solution
that may help, in the end it refers to 3ph also:

HYDRAULIC LOCK-OUT VALVE ON SCV DOES NOT WORK WITH 45 LOADER X400 AND X500 SERIES LAWN AND GARDEN TRACTORS


Complaint or Symptom:

Hydraulic Lock-Out Valve (AM131526) is installed on SCV coupler housing but:

- Mower deck (or other attachment) raises, lowers or moves when 45 front loader is operated.

-Delayed functions noticed in attachments when used with loader.

-Valve does not seem to stop hydraulic flow to mid-cylinder like previous 425-455 models.

Situation:

Early Operators Manuals did not have complete information on how to use valve.

Wrong procedure used when closing hydraulic lock-out valve.

Solution:
1 Fully raise mower deck lift arms and set mower cut knob to highest setting.

2 Lower deck lift arms with SCV lever to be sure it is against depth stop.

3 Close hydraulic lock-out valve.

Additional Information:

- Rockshaft must first be raised then lowered to depth stop before closing lock-out valve. Valve on X-Series is installed so it shuts off oil on opposite side of lift cylinder.

- If a 3-point hitch is installed, it must be locked up manually using the depth control adjustment at rear of the tractor.

- Instructions for installing the lockout valve are included in the appropriate attachment Operators Manual.

- Operators Manuals will be changed at next revision.