Brake hard line question

I'm finishing the hard lines on a '51 Chevy truck project. Over the years I've seen various vehicles with a few loops of brake line near the master cylinder. I never thought too much about it. I know a manufacturer wouldn't waste the time and money to make a line that way for no reason. "I guess we cut all these too long, just put a few coils here near the end"

So, is it for movement between body and frame on full frame vehicles? Heat expansion? Long term vibration issues that could cause a line to crack at a fitting? All of the above?

I can't remember the last full frame vehicle that I've had as a project. This is a '51 3100 on a modified S10 chassis. Its getting the brake booster and master on the firewall instead of the stock 3100 set up under the floor.

I have seen the brake line loops on older stuff as well and have no idea why it was there.  Maybe the material in the '50s lines was more prone to embrittlement?

The S10 is body on frame and I don't remember seeing brake line loops on mine.  Not needed due to improved materials?

Modern vehicles have more isolation between the frame and the body, = more movement.

There is also allowing the MC to move some in a crash and still be functional

bentwrench said:

Modern vehicles have more isolation between the frame and the body, = more movement.

There is also allowing the MC to move some in a crash and still be functional

Winner winner chicken dinner.

New vehicles (thinking unibody) generally have a flexible section between MC and ABS unit to isolate ABS pump vibration from driver's foot. Body on frame may have coil of tube or flex section, or maybe both, to provide isolation *and* accommodate relative motion between firewall and chassis.

Makes it quicker and easier to install on the assembly line without requiring rework;

time == money