Stress relief coils in brake lines?

[VictoriaHardware]

Originally Posted by Keith Seymore

It's because there is relative motion between the cab and frame during use.

The cab is mounted on the body mounts with the master cylinder hard mounted to the cab; the brake lines are hard mounted to the chassis. The cab will move between a quarter and a half inch due to jounce or twist.

Something's gotta give.

No relative motion between the wheel cylinders and the axle tube, which is why the brake lines can be hard mounted to the tubes (the suspension travel is taken up in the center with the rubber hose).

K

If you are making custom lines and there is sufficient freedom, coils are not necessary. Steel tubing will bend and twist without harm as long as they are given room. Say the master cylinder-to-frame line is held tight with a clamp to the body down near the frame. If the line is also held tight to the frame not far from the body clamp, then it could be a problem. If the two clamps are spaced further then you're OK. There are lots of vehicles without factory coils.

It also stands to reason that the factory did it for a good reason. If there was ever a chance to shortcut something and save 1 cent, they did it. They also had to design for the WORST case condition for 100K miles, which these trucks are probably not going to see again.

[Keith Seymore]

Originally Posted by VictoriaHardware

They also had to design for the WORST case condition for 100K miles, which these trucks are probably not going to see again.

This is true.

We also have to accommodate build variation from truck to truck across 1.5 million vehicles, which the enthusiast would not have to comprehend when doing 1 vehicle.

K