International standards allow 37-deg flared hydraulic fittings to be reused, provided they are clean and their threads and sealing surfaces are not damaged. Technicians and mechanics who have successfully completed training for IFPS Certification in proper procedures for hydraulic line connections know to make sure all threads and mating surfaces are clean and to tighten the fitting nut to the correct torque based on size.
But untrained or under-trained personnel may not understand the importance of ensuring that all mating surfaces of hydraulics fittings are smooth and clean. Furthermore, they may think that the greater the torque applied to a fitting, the less likely it is to leak. This practice happens all too often with 37-deg. flare fittings, which should be tightened using a torque wrench to within a prescribed window of torque values.
Regardless, damaged fittings are a reality at most facilities, which usually means replacing the fitting. If the exact fitting is not readily available about the only option is to do your best to smooth out the sealing surface of the fitting. This is time-consuming, and the “repaired” fitting will probably leak anyway.
A new option is the Fitting Fixer, offered by Koul Tools. Fitting Fixer uses an inverted cone lapping head coated with diamond dust to repair the sealing surface on 37-deg. fittings using a handheld power drill. They come in seven sizes for tubing sized from 3/16 to 1 in. and in sets.
Image courtesy of Koul Tools