The subject of bore of a hydraulic pipe in a vehicle braking system came up on our forum
http://www.chocksaway.com/phpbb/viewtopic.php?t=15028
and I wasn't certain of the answer, so I set out to find the experts and here I am.
The basic question was, if the inner bore of a brake pipe gets smaller than the original design, does it have any overall effect on the system?

Thanks for reading

Nige;

I would say most brake line is designed for mechanical strength more than flow capability.

If you look at a brake circuit on an automobile, the flow is practically none, as referenced from the amount of Brake Pedal Travel which is more than the actual Master Cylinder Piston travel due to mechanical advantage. Therefore a smaller diameter tube could be a help in response time of brake set and release but not be as physically strong.

In the 50's when I grew up and brakes had to be adjusted mechanically every 2-5,000 miles you just had more pedal travel to get braking action but not a great resistance from pushing the fluid to the brake cylinders.