This service can be performed by the factory, which is recommended. If you prefer and have the proper tools and skills to perform it yourself, follow the procedures below. Macro Sensors is not responsible for any damage if you take the unit apart. This is an at-your-own-risk procedure. If the unit is in warranty, you are advised to send it back to the factory.

Body of sensor should be held in a vise using cushioning material (such as a cloth folded over several times) around the sensor. Apply just enough pressure to hold the unit securely in place.

Remove snap-ring in the front bearing retaining groove located at the intersection of the bearing and the probe. Use a small pointed tool such as an Exacto-knife to engage the end of the snap ring and pull it out of the groove. Be careful not let the snap ring spring away. Make sure to hold on the the probe, there is a spring that will tend to push the assembly out.

Using your fingers to grasp the probe shaft. Pull the assembly out from the front. The front bearing may stick and may require the probe assembly to be run back and forth a few time to dislodge the bearing. You can use gloves that have a rubberized material to gain additional traction on the probe shaft. Since this is a precision fit between the bearings and probe shaft, under no circumstances are any metallic tools to be used to remove the plunger assembly. This will result in damage to the shaft and it will not. Make sure to take care and not drop or roll the plunger and core assembly. 

Important note: The core is very sensitive to abrasion of the surface. It should be thought of as a very thin piece of glass tubing and handled accordingly. 

The bearing should fall out with several light strikes of the front of the threaded portion of the housing on a malleable material like a piece of wood or very thick paper.

Place all pieces in a vapor degreaser or use a non-residue solvent to remove all contamination from the parts. Wipe shaft and inside diameter of bearings with a clean cloth. Flush out the internal bore of the LVDT with a non-residue solvent preferably an aerosol or forced method. Do not try and extend the spring to create added force this will only create spring bind to the probe shaft. You can order proper higher strength springs from the factory.  Make sure that all parts a dry before reassembly.

This operation should be done with the core and probe together. Do not take them apart.

Check to make sure that the Probe shaft and core assembly are straight. Use your fingers to manipulate the probe shaft and core.

Use a V-block and dial indicator to make sure that the plunger shaft is straight to with in about +/-.0015"TIR while rolling it in the block.

The core should be about +/- .0035" TIR. USE YOUR FINGERS to bend core. DO NOT HOLD CORE WITH ANYTHING THAT WILL DAMAGE THE SURFACE.  IF YOU DO YOU WILL NEED TO HAVE UNIT RECALIBRATED. Remember note in step 3.

Use a V-block and dial indicator to make sure that the threaded barrel portion is straight to within about +/-.005" TIR end to end. The body section is not relevant to the operation of the mechanical components.

Re-assemble in reverse order installing snap ring last. Make sure to get the snap ring seated in groove completely or it may dislodge.

Move plunger in and out of unit and rotate shaft and repeat. If it sticks repeat steps 6 and 7. If this does not solve the problem call the factory for further information.

All parts are available from the factory. We can perform the refurbishment of you unit. This will give you all new parts and calibration as necessary. Please call for pricing and availability.