Flossie
Well-Known Member
Cos the olive can crush the tube and not grip it well. I did all mine without them with no issues however. But for what they probably cost (peanuts?) You may as well use them.
Pipe crushes by over zealous tightening on the union, pipe deforms then the olive is unable to seal correctly and then you have a leak.
To be fair when I started spannering and brake/fuel pipes were still imperial they didnt use tube supports, but when it all went metric it seemed like tube supports became needed.
Maybe wall thickness decreased?
I used to work for a guy that made custom truck fuel tanks and he had tried everything over many years and in the end all fuel/air unions had to be to oe spec as they caused zero issues.
Even running a knife blads longways down the hose tail (leaving a scratch/very minor groove( was enough to allow air in, you had to cut the old pipe off as if you were slicing it off/skinnnning it
