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JLG 40 FRC Lift Schematics

4Mile

Member
Joined
May 1, 2015
Messages
10
Location
North Dakota
Occupation
Retired from Caterpillar GlobalPaving Products Div
To me the critical part is the circuit board, the mechanical side of the controls are fine.

The new control helped but the one track still is not functioning correct. Loads the hydraulic but moves a part rotation and locks. Remove the track jacked it off the ground and all seems fine with out any load. There are torque hubs on the front and rear drive wheels, rears are equipped with spring applied/hydraulic released brakes. Brakes are releasing completely.

Installed a flow meter in the lines from the Racine Control valve (after the crossover relief valve that is in the circuit). At operating engine speed, load valve open, 12 GPM at 500 psi in both flow direction. In reverse, load valve adjusted to 2000psi, flow drops to near 4 gpm. In forward, 2000 psi, near 9 gpm. I had checked valve null previous.

Next step is to install the flow meters in ahead and see what the flows/pressures are. Then its time to check the setting on the crossover relief.

Also, do any of you have a valid part number for the high pressure filters. There are only a total of 6 on this unit. Two in the same circuits as a FL series and 4 in the drive motor circuits (one on each side of each circuit)
 

lantraxco

Senior Member
Joined
Jan 1, 2009
Messages
7,704
Location
Elsewhen
One suggestion, keep in mind that relief valves may bypass oil without opening, had a couple cases years ago where the seats grooved out bad enough that the flow numbers were eerily similar to yours between no load and 2,000 psi, yet you could set the relief cracking pressure quite accurately.
 
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