Brake and fuel line "plumbing" questions

[smitty77]

Now that I have the frame painted I'm getting to work on getting the brake line and fuel lines put back on.  The truck is a 79 stepside with dual tanks, and does NOT need to pass an emissions test.

Fuel questions:
What size(s) are the feed, return, and vapor lines?
Do I really need a vapor line? (based on what I've read here: yes)
Does the driver's side tank have it's own vapor line to the canister?  When I took the whole mess apart, I had a line running on the outside of the drivers side of the frame rail, but it wasn't hooked to anything.  I also had 3 lines running between tanks.  I have no idea what this "extra" line was for.
How many outlets for the tank sending units?  I'm assuming 3 if I use a vapor line, but I've seen some with 4 outlets.  What are these for?

Brake Lines:
What diameter are the lines running to the rear drums? And are they supposed to reduced to 3/16" after the "T" on the differential housing?  I know the front brakes are 3/16" dia. but unsure if the rears are 1/4" or 5/16".
Do I need to chase down some of that armor for the brake lines?  If so, who carries it locally? (ie. NAPA or Advanced?)

Tranny lines:
Do the tranny cooler lines run inside the frame rail or more towards the motor? The lines to my tranny cooler looked like a hack job, and I'd like them to be properly done.

Thanks in advance guys.  When I get a few minutes, I'll post a build-up thread on the project, now that it's moving along again (with another parts truck to arrive soon   )

[VileZambonie]

If you are not hooking up the evap system all you need is a feed and return line. 3/8" feed, 5/16" return.

3/16" brake line is fine.

The cooler lines are run past the oil pan up to the radiator.

[smitty77]

If you are not hooking up the evap system all you need is a feed and return line. 3/8" feed, 5/16" return.

3/16" brake line is fine.

The cooler lines are run past the oil pan up to the radiator.

Thanks Vile, I knew you'd have the answers.  If I want to keep the evap system (you had a few posts in the archives that suggest keeping it for correct tank venting), is that also 5/16", or 1/4"?

As for the brakes, it's okay to run 3/16" on that one long leg from the proportioning valve out to the T on the diff?  Is there a reason the factory line seems larger (like 1/4").  Keeping it all 3/16 is a lot easier for me, I just want to make sure it's all correct before it all gets fastened in and blocked off by my engine mounts.

Thanks again,
Smitty

[VileZambonie]

The vent line is usually 1/4"

Realistically the size of the brake lines really don't matter. Pressure in an enclosed container remains constant and equal throughout the system. If you are concerned about fluid fade then larger lines are more desireable for better heat dissipation.

[smitty77]

Realistically the size of the brake lines really don't matter. Pressure in an enclosed container remains constant and equal throughout the system. If you are concerned about fluid fade then larger lines are more desireable for better heat dissipation.

This is what I remember from physics and my college fluids dynamics class.  Just couldn't figure out why the larger line up to the T.  Fluid fade makes sense, but I don't plan on having heat issues as it will be mostly a cruise vehicle.

Thanks again,
Smitty

[HAULIN IT]

I would run the 1/4" line from the distribution block to the rear hose for the simple reasons that you don't need an adapter/special fitting at each end, also if your frame clips are still good, they are already there for you. In this case I can't see any reason to deviate from stock. Just my Two cents, Lorne 

[smitty77]

I'm still hashing out the master plan.  It turns out I need to buy some 1/4" and 5/16" for fuel line (my 3/8" stuff is still good), so I may go ahead and get some 1/4" for the brakes.

Is it okay to use the same type of tubing for fuel?  The brake tubing I got was some coated stuff from Advanced Auto in a 25' roll.

[smitty77]

More "plumbing" questions:

What sizes are the threaded fittings on the ends of each line (behind the flare)?  The boys at Advanced sold me a package of 10 that reads "3/16 x 1/4 nut", but they're too big to thread into the proportioning valve or the brake hose protruding from the frame.  Are OEM sizes metric?

While we're at it, what about the larger sizes for the 1/4" line and for those going into the master cylinder?

In terms of progress, I got the front lines bent yesterday using the old as a pattern.  They came out pretty nice for a rookie.