Fluctuations of up to 50 PSI are normal for operation of the hydraulic power unit (HPU). The fluctuations do not affect machine operation or performance. For larger surges in pressure, check for oil contamination or a low oil level.
Possible Cause: Internal components are worn or damaged.
Internal components will get normal wear and tear from the constant movement of the pointer across the scale.
Corrective Action: You must replace the entire gauge assembly.
Remove the incoming pressure to the gauge assembly. Rotate the gauge counter-clockwise to remove it. Gauges that do not have clearance to remove by rotation have swivel fittings . Use two wrenches to hold the fixed portion of the adapter fitting , and another to turn the swivel fitting .
Verify you have the correct gauge for replacement (scale, fittings, etc). Check for the snubber and install the new gauge assembly clockwise and tight. Be sure to use thread sealer when needed.