I recently posted  that my  trail a mate jack was not working and sought advice from those who had serviced their own with the service kit.  I did service my own but it  still would not lift.  I rang the company in SA,  (Seatra International) and spoke with the co owner and inventor who asked me  to bring it to their  ware house and workshop at Clovelly Park. Sean or Shaun (not sure)  the co owner pulled it apart and replaced the metal check valve, tested and all OK.   I offered to pay but was refused saying the repair was free. The jack is six years old so I am rightly impressed with the service of this company. He also gave me an extendable caravan wheel brace and an extra for a friend. . The brace is magic.  So here it is 10 out of 10 to the suppliers of Trail a mate.   Cheers  Daz