Service Home Tool Release Piston - Troubleshooting Guide - TG0146
Last updated: 10/15/2025

Tool Release Piston (TRP) - Troubleshooting Guide

TG0146

Introduction

  1. ROTARY UNION
  2. SPRING RETAINER
  3. COMPRESSION SPRING
  4. SHCS 8-32 X 3/8
  5. PROXIMITY SENSOR
  6. SHCS 1/4-20 X 2
  7. SWITCH MOUNT BLOCK
  8. O-RING 2-121 BUNA
  9. SHCS 3/8-16 X 5
  10. FITG HOSE BARB1/2 NPT1/4M STR BRASS
  11. FITG NPT1/8M PLUG STL W/THREAD SEALANT
  12. TRP HOUSING
  13. SPACER UPPER
  14. TRP PISTON
  15. O-RING 2-446 BUNA
  16. O-RING 2-015 BUNA
  17. VALVE CHECK NPT-1/8-F X NPT-1/8-F BRASS
  18. O-RING 2-327 VITON
  19. SPACER LOWER
  20. TRP SHAFT
  21. TRP SUB-PLATE
  22. TRP FORK SPACER
  23. TRP FORK
  24. WASHER 1/2 STEEL .018THK X 1.00O
  25. SHCS 1/2-13 X 3 1/2

 

  1. 40-taper
  2. 50-taper
  3. 40-taper inline drive

Symptom Table

Symptom Possible Cause Corrective Action
The TRP does not activate when commanded. The solenoid is inoperable. Test the solenoid.
The air volume is low. Check the air system.
Parameter 71 is incorrect (CHC). Check the value of Parameter 71
Alarm 134 TOOL CLAMP FAULT occurs on machines with M18.27 and lower. The air volume is low. Check the air system.
The retaining ring that holds the drawbar actuator pins is defective (Inline Spindle Only). Replace the spindle with the latest revision of the spindle, which uses a roll pin to retain the drawbar actuator pins.
The bearingless union loosened from the center shaft (50 Taper Only).
  1. Remove the TSC parts from the TRP.
  2. Remove the TRP.
  3. Tighten the 50 Taper union adapter to 100 ft-lbs (136 Nm). Use a 5/8" hex tool to hold the center shaft in position while you tighten the 50 Taper union adapter.

    Note: The spring retainer on the TRP energizes the TRP proximity-sensor. The spring retainer changes height when the 50 Taper union adapter loosens from the center shaft.

  4. Install the TRP.
  5. Make sure the spring retainer energizes the TRP proximity-sensor.
  6. Install the TSC parts onto the TRP when the 50 Taper union adapter is tightened correctly.
Alarm 134 TOOL CLAMP FAULT occurs on machines with M18.28 and higher. A ground wire is loose in the electrical cabinet. (Next Generation Control Only) Make sure all of the ground wires that are inside of the electrical cabinet are tight. Make sure all the of axis motor-cables are tight.

The TRP hits the drawbar and makes a loud banging noise.

 The precharge regulator is not adjusted properly. Properly adjust the precharge regulator. Refer to the Precharge Regulator section below. 
Precharge pressure incorrect on a fixed regulator. Replace the fixed regulator. Refer to the Precharge Regulator section below.
The TRP does not push out enough to release the tool. There is an air leak. Check air system and low air delay Parameter 76.
The drawbar is damaged. Inspect the drawbar.
The TRP pushout is not properly adjusted. Verify and adjust the drawbar height.
The piston o-ring has no lubrication, or the piston/bore or o-ring is damaged. Replace the TRP.
The TRP retracts slowly.

Alarm 130 TOOL UNCLAMPED

Alarm 131 TOOL NOT CLAMPED.

 The return spring is broken. Replace the TRP base assembly.
The humphrey valve is worn.
 A worn humprey valve (quick exhaust valve) can cause air to leak into the piston and cause the TRP to retract slowly. Replace the humprey valve.
The exhaust muffler is clogged. Test the exhaust muffler.
The piston o-ring has no lubrication, or the piston/bore or o-ring is damaged. Inspect the piston o-ring.
The precharge solenoid is getting stuck due to contamination. Inspect the precharge solenoid for contamination. For CALM machines inspect solenoid manifold inside the lube panel for contamination. See Water Separator Filter section below.
The inline spindle is seized. The inline spindle won't turn.

Machines with I/O PCB 34-3490A/B

Intermittent Alarm 131 TOOL NOT CLAMPED
                         AND
It is using a Digital SMC Solenoid.

 There is a small delay when the solenoid is commanded off, thus causing the alarm to be generated.  Order service kits 93-3451 & 93-3452 and follow the Low Load Solenoid Valve Kit - Installation procedure.

Solenoid

Corrective Action:

Clean the solenoid valve.

Press and hold the tool release. Check the voltage to the solenoid. It should have 120 VAC. If there is no power, make sure it has a good connection to the I/O PCB.

If the connection to the I/O PCB is good, refer to Solenoid - Troubleshooting Guide to troubleshoot the solenoid.

Air Pressure

Corrective Action:

Check the air pressure supply.

Check the air volume supplied to machine. Refer to the Air Requirement section in the New Machine Setup / Pre-Installation for required hose size and other instructions.

Check for air leaks in supply hose / solenoid exhaust / TRP.

Verify Parameter 76 Low Air Delay is set to 1500.

Parameter 71 - Classic Haas Control (CHC)

Corrective Action:

Check the value of Parameter 71, DRAW BAR OFFSET.

Model P71 Value
(Sigma 1 Motors)		 P71 Value
(Sigma 5 Motors)
DM/DT N/A 0
EC400 0 0
EC1600 6000 40000
ES 6936 0
GR 12000 66600
GR408 12000 0
MDC 12000 0
Mini Mill 12000 111000
S Mini Mill 12000 66600
Office Mill 12000 12000
OM1A, OM2A 14000 112000
SR 12000 0
Toolroom 12000 111000
UMC N/A 66600
VF1-VF4 12000 83300
VF2SS-VF4SS 6936 55500
VF5/40-VF12/40 6936 66600
VF3/50-VF12/50
 12000 40000
VM2-VM3 6936 111000
VM6 12000 111000
VR 12000 0
VS 12000 0

Precharge Regulator

Corrective Action:

Adjust or replace the precharge regulator:

  • Adjustable regulator [1] - Properly adjust the precharge regulator. If the precharge regulator is damaged and is unable to adjust, replace it.
  • Fixed nonadjustable regulator [2] - Verify the pressure, replace the precharge regulator if pressure is incorrect.

Note: 40T inline spindle machines (VF,VM,UMC) built after February, 2017 do not have a precharge regulator. Refer to: HSG-N 06-05-2017

Drawbar

Corrective Action:

Remove and inspect spindle drawbar for broken spring washers or any other damage.

Inspect spindle drawbar for damaged o-ring seals (TSC machines only). Go to Spindle - Drawbar - Troubleshooting Guide to troubleshoot the drawbar.

Return Spring

Corrective Action:

If the return spring is broken, replace the TRP base assembly.

Pushout

Corrective Action:

40T TSC Belt Drive Only - Inspect the TRP tool release bolt, or carbide tip for excessive wear or damage.

Verify the spindle drawbar pushout and sensor adjustments.

Adjust the height by adding or removing shims. Refer to the TRP switch adjustment procedure for more information.

Exhaust Muffler

Corrective Action:

Remove the exhaust muffler from the solenoid and test TRP operation. Replace the exhaust muffler if necessary.

O-ring

Corrective Action:

40T Belt Drive Only - Remove the TRP and apply lubricant to the TRP housing [1].

Install the TRP on the machine and in the correct place. Cycle the machine. DO NOT ACTIVATE TRP WHEN THE TRP IS NOT IN PLACE, DAMAGE TO THE TRP MAY OCCUR.

The TRP base is not serviceable due to the high spring pressure. If damaged, the assembly must be replaced.

Water Separator Filter

The filter in the water separator can come loose inside of the water separator casting. The filter moves around inside of the canister and breaks into small pieces. These pieces contaminate components in the pneumatic systems. You should always check this filter when troubleshooting any pneumatic problem.

Corrective Action:

  1. Remove and replace the water separator filter [2] (P/N 58-1391; Muffler Poly 100 Micron NPT-3/8M). Put Sikaflex on the threads of the filter.

     Note: Use spark plug pliers or a similar tool to loosen and tighten the filter.

  2. Remove and clean the casting [1], the O-ring [3], the screen [4], and the cap [5]
  3. Remove and clean the solenoids.
  4. Remove and clean the air mufflers.
  5. Remove and clean out the all of the pneumatic tubing with compressed air.