I am replacing the brake lines on a 2001 GMC Jimmy. Do I need to match the bends of the old ones exactly or can I just run the lines straight to make it easier to install? Does the length of the new line need to be the same as the old one?
You may want to consider buying a pre-bent brake line kit for your 2001 Jimmy.
It's more expensive but all the lines come with the proper bends in them, the double-flares on each end, with the male fittings.
I've done complete brake line replacements both ways.
Buying coils of brake line, using each section of old brake line as a "pattern" to make the new bends, and making the double flares on each end of the line sections with a flaring tool
and
buying a pre-bent kit.
The pre-bent kits are the way to go. You disconnect a section of brake line and put in the new pre-bent section.
For me it's worth it just not having to make all those double-flares. I don't use a flaring tool very often. I can go years without breaking out my flaring kit. There's a knack to getting those double-flares just right and if you aren't in practice it's aggravating.
The pre-bent lines are a good way to go, but if you do decide to roll your own I recommend using Ni-Copp brake line. Very easy to work with and it won't corrode.
You should try and match the bends as close as possible. It doesn’t have to be exact but the length and bends in the line will affect pedal feel because it needs a certain amount of area for fluid pressure for pedal cushion
