Bastard sized Inverted Flare Nuts

50C8DAN
50C8DAN Senior Contributor
edited September 2020 in HUDSON
I wanted to pass on something I found out the hard way on some of the inverted stainless flare fittings on my brake conversion.  I purchased my distribution block from Speedway and it came with two short stainless lines to connect it to the MC.  The lines were already flared with stainless fittings.  When I connected it I only finger tightened the lines so I could adjust them once it was mounted and in place.  This is not as easy as I thought as the fittings on the MC I used were on the right side toward the engine and the brake light switch was in between the two connectors on the right side of the block.  Well as I tried to tighten them I could not get my 3/8" tubing wrench or even open wrench to fit on the nuts!  I thought what the hey here!!  I then realized that the lines were supposedly 3/16" but the fittings were METRIC!  The nuts were 10mm, luckily I had a 10mm tubing wrench, which I had never used for all of probably 30 years. Anyway I went on line and found that others had had issues with other supposedly English sized tubing nuts that turned out to be metric, but were advertised as 3/8 x 24 for 3/16" tubing, also some found oversized ones at 12mm.  So I am guessing these came from China and are bastard mix of English tubing with metric sized nuts on the outside and English 3/8-24 threads.  So be aware this may happen to you!  

Comments

  • I've seen this issue on brake cylinders.  The fitting threads are correct, the mounting threads are correct, but the bleed screws are metric heads.  Yes, it is very frustrating!
  • bob ward
    bob ward Senior Contributor
    Metric hex sizes are very common on import English thread tube nuts, 10mm hex instead of 9.53mm (3/8") for instance. I don't lose too much sleep over it.
  • 50C8DAN
    50C8DAN Senior Contributor
    Inline tube is still all English at least.  

  • That's the trouble when the whole world is metric but not the USA. 
  • 50C8DAN
    50C8DAN Senior Contributor
    Well perhaps, but when you are working on a 66 year old car that cannot speak metric it is a problem.