Supplying Climate Control Systems to the Vehicle Market for Over Half a Century.

Assembly Instructions for Metal to Rubber Fittings



  1. Cut end of the copper tube with a sharp tubing cutter; remove external burr with a file. Carefully cut out the internal burr so that shavings do not drop into the tubing. (Do not allow any burrs or foreign material to fall into the tubing.)
  2. Place the hex nut (tapered end first) over the copper tubing stub, then install the ferrule with the small end toward the nut. (Do not install O-ring.)
  3. Push the rubber hose compression fitting and tubing stub together. The tube must bottom out inside the hose compression fitting and remain bottomed while the nut is tightened by hand (finger tight).
  4. Push the ferrule and nut against the compression fitting nut and tighten assembly 1/2 turn with wrenches. This crimps the ferrule into position on the copper tubing stub.
  5. Disassemble the connection. Lubricate the O-ring with refrigerant oil and install the O-ring onto the copper tubing stub until it is against the ferrule. Reassemble the connection and tighten by hand (finger tight). Use wrenches to tighten the connection assembly an additional 1/4 turn.


Do not tighten more than 1/4 turn. Correct total ferrule compression (assembly torque) is achieved at 3/4 turn with wrenches (1/2 turn per step 4 and 1/4 turn per step 5).

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