Product Selector   Gemco 1997 Gate Hoist Lmt Swtch Gemco Stamping Press Control Gemco 1980 Micro-Adjust Cams Gemco 1980S Limit Switch Manual Gemco 2000 Rotary Limit Switches Gemco 3001 Adjustable Couplings Brake Systems Application Guide Model CB/TM Brakes Manual Model ET Shoe Brakes Manual Model H Shoe Brakes Manual Model H Brake Parts Manual   Hydraulic Brakes Replacement Parts:     Brake Assemblies     Auxilary Components     Air-Releasing Cylinder Disc Brake Power Clusters Air-Over-Hydraulic Panels Air-Over-Hyd. Panel Components     Auxilary Components:       HM Control Units       Hydraulic Brake Actuator       Control Cylinder and Pedal       10, 14, and 18 HM Parking Cylinder       Misc Fittings, Tubing, and Accessories       Fluid Reservoir Bleeder and Pushbutton

And   Or     All Site   Selected Product Order Details Items 0 Total $0.00     Logon Status Not logged on Download  GEMCO Hydraulic Brake Systems Parts Manual:    Microsoft Word® 97 format (8.0 MB)    Adobe Acrobat® format (3.6 MB) Get Viewer Get Reader

GEMCO Industrial Brake Systems Replacement Parts
AUXILARY COMPONENTS
HM Control Units
 
HM Control Unit J107206 (Replaces J070930 and J107154)
 

The HM Control Unit traps pressure in the HM park release cylinder circuit when solenoid is energized.   Brake fluid displaced by the control cylinder flows to port A. Beyond that point it divides, part flowing past port A to the service brake cylinder and part flowing past the check valve, port B and to the HM park release brake cylinder. Normal maximum force on the brake pedal will develop 400 psi to fully compress the parking spring. If the solenoid is energized the check valve traps this pressure to keep the parking cylinder released even after the pedal force is released and pressure in line A-A drops back to zero. Subsequent pedal force develops pressure at the service brake cylinder, while the parking brake cylinder remains released as long as the solenoid is energized.   The solenoid consists of 115V DC coil which is factory connected in series with a resistor for 230V DC operation. The TSRM rectifier is series connected in the DC circuit to suppres any transient voltage surges. If the system is operated at 115V AC, the coil must be re-connected. See wiring diagrams on the door of the control unit.

Item No. Part Description No. Used Part No. 1 2 3 4 5   6 7 "+" "*" N.O. Pressure Switch TSRM Rectifier Kit 1/2-20 Union Swivel Fitting Solenoid Check Valve Assembly Solenoid Only Resistor Valve Stem with Seals Conversion Kit 1 1 3 2 1   1 1 1 1 J024684 J071053 J049087 F003163 J107151   J107148 J107149 J107156 J107155   +   Value stem is located within Solenoid Check         Valve Assembly.   *   Conversion Kit includes resistor, washers,         fittings and hose (hose from valve to H         cylinder port, valve to HM cylinder port,         valve to pressure switch).   Whenever electric power is ON and the parking switch in the cab is CLOSED, the solenoid check valve holds pressure in the parking brake release cylinder. This pressure also operates the normally open hydraulic pressure switch, which closes above 400 psi, when the parking brake should be fully released. The closed pressure switch operates the green signal light in the cab and the drive motor pilot relay.   If power to the system is disconnected the solenoid check valve will release the trapped pressure. The pressure switch will open 320 psi - turning the green light OFF and opening the motor pilot relay. The parking brake will reset below 320 psi.   For the HM brake system to function properly. The HM park release hydraulic circuit as well as the service brake hydraulic circuit must be filled with brake fluid and be bled free of air. The service brake circuit is bled by operating the bleeder, however the parking brake circuit must be bled manually. The HM brake must be properly adjusted. Final brake adjustment is necessary after the hydraulic circuit is operational and the parking cylinder can be fully released. When properly adjusted - one full stroke of the pedal is all that is needed to fully release the parking brakes for normal service brake operation. There can be NO external or internal leaks in the hydraulic system. Visible external leaks must be corrected. The power supply must be ON and there must be 230V or 115V DC across "+" and "-" terminals at the terminal board. The solenoid must be connected for the correct voltage. Check color code of lead wires carefully. Check operation of the TSRM rectifier. If all of the above conditions have been checked and are normal, and the park release cylinder will not stay released then the problem can only be a leaking solenoid check valve and/or a leaking HM park release cylinder.

Note: To modify existing J070930 or J107154 HM Control Unit to J107206, order J107155 Kit and J107151 Solenoid Valve Assembly.