Quote:
Originally Posted by 97 SL320
Not always. Some AC fitting tubes are smooth / near smooth for easy hose assembly and the ferrule is locked / crimped to the fitting with the shape of the crimp mimicking a " barb " or " rings " , this prevents hose blow off.
Hydraulic hoses fittings are built this way as well.
Old style field install hose fittings have barbs to prevent hose blow off when used with a screw clamp. " AC " spec hose clamps have a leg that gives proper spacing so pressure is applied to a smooth area just past the barb. Standard non leg clamps are fine if the spacing is properly set.
When replacing factory ferrules with crimped on ones, be sure that the ferrule is crimped to the notch on the fitting.
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Agreed. Removing the old rubber and ferules and then clamping on new hose (must be metric) with any kind of clamp will allow the hose to blow off. This is especially true when using 134a, as the pressures are higher than R12 or Hydrocarbon refrigerants. I use new steel beadlock fittings in all the hoses I make. If I am using a factory metal manifold or pipe, I have a barb welded (brazed) on, and crimp my own hoses on.