Hi SMKU, I know YOU already got it apart, but here is some suggestions, that I posted a few years ago, that WORK for ME!! First, always rinse ALL Water Detectors off with a HOSE
to get MOST or ALL excess S-A-N-D off the Detector, and also from INSIDE the COIL Cover!! Then, take YOUR Water Detector into a Semi-HOT S-H-O-W-E-R, and
THOROUGHLY RINSE the ENTIRE Detector OFF, and Especially FORCE Mild HOT Water DOWN Inside the UPPER Shaft, and AROUND the CAMLOCKS to remove any REMAINING Sand!! But, it will HELP You ALOT if Replace the CAMLOCKS with Pluggers SHAFTLOCKS, and I HIGHLY Recommend YOU do so!! YOU can S-A-W Off the CAMLOCKS just above the Top End, and then just SLIDE the SHAFTLOCKS Over the End of the UPPER Shaft!!, the SHAFTLOCKS have a Stainlees Steel or Vinyl SET SCREW, that YOU T-I-G-H-T-E-N Up!! Also, the Shaftlocks are Easily Removable if YOU want or need to!! Finally to HELP with FREEING a STUCK Lower Shaft!! Try G-E-N-T-L-Y TAPPING on the Bottom of the Center of the COIL with a RUBBER Mallet, while HOLDING the Spring Clip BUTTON I-N!! YOU just have to MOVE the Spring Button Clip B-E-Y-O-N-D the Shaft HOLE, and GENTLY T-W-I-S-T the Lower Shaft at theCOIL!! Then once YOU Break It FREE, gently PULL the Lower ROD Out of the UPPER Shaft!! Aluminum UPPER Shafts O-X-D-I-S-E in SALTWATER, so YOU have to T-H-O-R-O-U-G-H-l-L-Y CLEAN the INSIDE of the UPPER SHAFT with a 12ga. Shotgun Cleaning Rod and BRASS or STAINLESS Steel BRUSH Tip, or Cheaper Yet, get a 3/4" ALL T-H-R-E-A-D Rod that is about 2' or 3' LONG at any HARDWARE Store (that's what I PERSONALLY Use)!! This will remove the OXIDIZED Aluminum B-A-R-B-S, that are Created by Saltwater USE!! Finally, S-P-R-A-Y the INSIDE of YOUR Aluminum UPPER Shaft with MARINE S-I-L-I-C-O-N-E SPRAY. I-M-P-O-R-T-A-N-T, DON'T Use any SPRAY, that has P-E-T-R-O-L-E-U-M in the Ingredients, because it is HARMFUL to PLASTIC and RUBBER Coatings!! BEST of LUCK!! Les Robinson.
P.S.: If YOU can AFFORD it, PURCHASE One of PLUGGER'S Carbon Fibre RODS!! I did a COUPLE of Month AGO, and I really L-I-K-E IT (he makes all his RODS with M-O-R-E
Adjustments, than other manufacturers!!)