Service Home Hydraulic Chuck - Troubleshooting Guide - TG0085
Last updated: 10/14/2025

Hydraulic Chuck - Troubleshooting Guide

TG0085

Introduction

Symptom Table

Symptom Probable Cause Corrective Action
Part moving in the chuck. Low clamp force. No lubrication Grease the chuck.
Incorrect hydraulic pressure Adjust the hydraulic pressure.
Incorrect chuck setup Inspect the chuck setup.
Finish issue or taper in the part. Incorrect hydraulic pressure Adjust the hydraulic pressure.
Incorrect chuck setup Inspect the chuck setup.
Loose or damaged jaws Inspect the chuck.
Alarm 9505 or 9505.001 COMMANDED PRESSURE NOT REACHED. The commanded device pressure was not reached within the specified timeout.  Check electrical connections to the pressure switch or motor or for failed hardware such as the pressure valve, hydraulic motor, or coupler.
Chuck wont Clamp or Unclamp Hydraulic pressure blockage Inspect actuating solenoid and hydraulic block

Inspect Actuating solenoid and Hydraulic Manifold

Corrective Action:

Verify the Hydraulic actuator is recieving the proper amount and direction of hydraulic fluid flow. Disconnect the hydraulic lines and place them into a bucket or other item to catch the hydraulic fluid. Clamp and Un-clamp the chuck observing for fluid flow from the proper hose location.

If no flow occurs or flow only occurs from one hose, troubleshoot the root cause by removing the actuating solenoid and inspecting it for chips or other debri that could cause a blockage.  If the solenoid is clean, remove and inspect the Hydraulic manifold for debris.

Reference this Video on How to clean a Hydraulic Solenoid

Lubrication

Corrective Action:

Grease the chuck. Lack of lubrication can greatly reduce the clamp force in a chuck.

Hydraulic Pressure

Corrective Action:

Set the hydraulic pressure correctly for the size and material you are cutting.

Too low of pressure can cause the workpiece to spin or pull out of the chuck.

Too high of pressure can cause the chuck jaws to “heel” on the part allowing it to move creating finish issues. High pressure may also cause the part to be deformed.

Type psi Bar
5" Chuck 330 23
6" Chuck 330 23
8" Chuck, 2" Bore 330 23
8" Chuck, 2.5" Bore 260 18
10" Chuck 330 23
12" Chuck, 3" Bore 400 28
12" Chuck, 4" Bore 250 17
15" Chuck 340 23
18" Chuck 300 21

Chuck Setup

Corrective Action:

Select the correct jaw type for the material being used.

  • Rough, unfinished bar stock is held better with hard jaws.
  • Clean or turned stock is held better with soft jaws.

Jaw marks can also be reduced or eliminated with soft jaws.

Refer to this video information on how to properly cut soft jaws.

Use a feeler gauge to check for gaps between the chuck jaws and the work piece when clamped. Make sure the jaws grip the part in the middle of the jaw stroke.

Use a spud or boring ring to properly load the chuck before cutting soft jaws.

Chuck Jaws

Corrective Action:

Remove the workpiece and clamp the chuck. Check each chuck jaw for motion, there should be none.

If there is motion, check if it is in the master jaw or in the removable jaw.

  • If there is motion in the master jaw, the chuck is damaged.
  • If there is motion in the removable jaw, inspect the bolt length and T-nut.