Building brake lines........need some help

[NW Task Force]

Ok folks,

I went out and bought several 3/8-24 inverted flare nuts and 3/16" steel brake line. The thing I am trying to learn/understand is why the master cylinder brake line connection bosses are so much larger than the 3/8-24 IV nuts? It looks like both bosses are different sizes.....what is the reason for this? What exactly do I need to adapt the 3/8-24 IV nuts to the master cylinder? I found some old fittings laying around in my toolbox. These fittings were used to "cap off" master cylinders for testing. It appears one fitting is roughly 1/2" and the other 7/16". I am new to the world of building brake lines......need some basic knowledge of fitting sizes and such.

[JumboAMONGus]

i went with the power brake master cylinder booster kit , , then it was pretty easy , i know the reason for a bigger one to the rear i think is because bigger hose since one line goes to the rear and then splits at rearend where the fronts would be one hose to a metering block that splits to two smaller hoses to the front brake wheel cylinders or calipers

[jfortvalley]

there is an adapter to go from 7/16 to 3/8 on the master cylinder

[Rude Dude]

The lines to rear drums take less pressure than disc front hence bigger lines

[1project2many]

1) The fittings are not going to tell you what size line is required. You can buy the fittings you're asking about for 3/16" and 1/4" brake line. Any good parts store will carry specially sized "brake line nuts."

http://store.fedhillusa.com/a123.aspx
http://store.fedhillusa.com/a234.aspx

2) The rear brakes have larger lines because unlike disk brakes, the shoes are pulled away from the drum by springs leaving a greater amount of distance between drum and shoe than between pad and rotor. Also, the brakes may get slightly out of adjustment from time to time which only adds to the clearance between drum and shoe. The master cylinder has to move a large amount of fluid quickly to make up this distance so the entire system can be pressurized enough to begin stopping the vehicle.

[OrrieG]

The lines need to be routed thru a proportioning valve. If the MC and PV are mounted low on the frame and the calipers and/or wheel cylinders can fall below the MC and PV (lowered truck) you will also need check valves to keep the pressure. Adding to the previous post, disc brake pads drag on the rotors slightly so the fluid volume required to move them is less. Pay attention to the line size and routing for stock systems, especially how the lines split at junction points, and you will be ok. Length is usually not a factor, pressure stays the same, but line size which affects volume is. Buy a good bending tool, a cheap one will crimp not bend the lines. Same with flaring tools. You can get preflared lines with fittings at NAPA to minimize the number of flares you need to do.

[_Ogre]

my mc is from an 03 mustang cobra w/hydroboost it is disk/disk and have 2 different line sizes
since i used the cobra distribution block/valve too, i used a 3/16 and 1/4 in line to the block
then adapted the 1/4 line down to 3/16 line after the distribution block

i found all the adapters i need from the local autozone or murry's
don't be confused by the 1/2 and 7/16 that is not the size
3/16 inverted flare and 1/4 inverted flare is the proper size

to add to orrieg's post (i was typing when he posted)
i didn't buy a roll of tubing, the kit i bought had 5- 5' long straight tubes in it,
i added a couple of shorter straight pieces to it.
longer pieces are not needed due to the residual valves that act like a splice

[arturo7]

Are there any advantages to fabbing the lines yourself versus buying one of the kits?

[Kabwe]

Originally Posted by arturo7

Are there any advantages to fabbing the lines yourself versus buying one of the kits?

Yes, the great thing about fabbing is you are only limited by your imagination. I prefer to bend and flare my own lines.

[_Ogre]

plus you really can't buy a pre-bent kit for a hotrod/custom
the kit i bought was straight lines, a whole lot of fittings, flex lines, spiral wrap, clips, residual valves and banjo bolts
i wanted stainless steel and couldn't find it locally
i ordered it from inlinetube.com

[NW Task Force]

Wow!

Thanks for all the great info guys! The bottom line is that I am running discs in the front and rear. Can I use 3/16" steel line on the entire system? I figured I might need to use adapters at the master cylinder to make this happen. I have already bought a 25ft roll of 3/16" steel brake line, the Inverted flare nuts, proportioning valve, correct 2psi residual valves, and Tee for brake light switch. Is the ports at the master cylinder considered "Inverted Flare Male"? I am still learning which fittings are what.

[1project2many]

You could use 3/16" line for the entire truck with 4 wheel discs. In the OEM world parts are sized to work together. Disc brake calipers have a larger volume than wheel cylinders and they hold more fluid. Because of the disc brake design, as pads wear more and more fluid ends up in the caliper which empties the master. A drum brake master or a disk/drum master often doesn't store enough fluid in the drum side to keep the system full over time. Will it work? Yes. Should you be checking fluid more often? Most likely. If that master above is from a Hydroboost unit you're probably OK but if it's from a car or 1/2 ton truck you might want to consider something intended for disk brakes.

Male and female fittings... think about it. The holes on the master are female. Parts that insert into those fittings... male. And yes, they are inverted flare.

[NW Task Force]

Thanks for the reply. The master cylinder I have is an aftermarket "under the cab" unit that is specifically for 4 wheel discs application on a 55-59 pickup. I believe I purchased it from "Zigs" Hot Rod Parts many years ago. At this point, I think I have the brake parts established on what I need. It seems using the "master cylinder adapters" is the way to accomplish 3/8"-24 flare nut fittings on both master cylinder outlets.

Originally Posted by 1project2many

You could use 3/16" line for the entire truck with 4 wheel discs. In the OEM world parts are sized to work together. Disc brake calipers have a larger volume than wheel cylinders and they hold more fluid. Because of the disc brake design, as pads wear more and more fluid ends up in the caliper which empties the master. A drum brake master or a disk/drum master often doesn't store enough fluid in the drum side to keep the system full over time. Will it work? Yes. Should you be checking fluid more often? Most likely. If that master above is from a Hydroboost unit you're probably OK but if it's from a car or 1/2 ton truck you might want to consider something intended for disk brakes.

Male and female fittings... think about it. The holes on the master are female. Parts that insert into those fittings... male. And yes, they are inverted flare.

[dapolice1]

Originally Posted by _Ogre

plus you really can't buy a pre-bent kit for a hotrod/custom
the kit i bought was straight lines, a whole lot of fittings, flex lines, spiral wrap, clips, residual valves and banjo bolts
i wanted stainless steel and couldn't find it locally
i ordered it from inlinetube.com

Which flaring tool did you use for the stainless lines? I know that stainless is more difficult to flare correctly than aluminum or steel.

[Kabwe]

Originally Posted by dapolice1

Which flaring tool did you use for the stainless lines? I know that stainless is more difficult to flare correctly than aluminum or steel.

I know the question was not asked of me, but when doing stainless steel lines it is best to use a 37 degree flare. I use stainless steel for fuel lines and my tool of choice is the Ridgid 41162 #377 Ratchet Flaring Tool (it's rated for stainless steel which is very important) because of price and performance. It flares stainless steel beautifully and its only a little over 100 bucks. You can get it here for 108 and free shipping. You will not be sorry.

http://www.faucetdepot.com/faucetdep...m#.UKJ_OWc0O9s

Are there fancier tools? Yes but they come with a big pricetag.

[_Ogre]

Originally Posted by dapolice1

Which flaring tool did you use for the stainless lines? I know that stainless is more difficult to flare correctly than aluminum or steel.

you are correct, i had a flare tool but it wouldn't double flare ss,
i ended up tearing it up and bending all the tooling
i rented one from murry's it was worse than mine
my neighbor had a blue point by snap-on that barely managed to double flare the ss lines
i'd clamp the flare tool clamp in a vise to keep the ss lines from pushing back in the clamp
with the straight line kit and the few extra short lines i bought i only had to double flare about 10 ends
that was my savior

all my lines are ss, fuel lines with the single flare and AN collar were easy
i have a friend that has a snap-on hydraulic tool that does the bubble flares and the flat crimp for the new style gm fuel filter
he helped with fuel lines and trans cooler lines to the radiator
he said the hydraulic machine does the double flares fine, so i'd try to find one of those to rent

[1project2many]

That hydraulic tool is made by mastercool. There are several versions with reduced die sets to save money. I've had mine since about '02 and it gets used frequently.

[_Ogre]

not just cool
mastercool
should be my forum name

[dwcsr]

I use the http://www.faucetdepot.com/prod/Ridg...p#.UKLj0sWHJu0 for 45* flares. Its like the 377 but not 37*. If you use it on the fedhill Cunifer tubing you will never ever use steel line again or any other flare tool other than the ridgid flare tools. Hyd flaring tools are nice but expensive for a seldom used tool.

[mknittle]

I am thinking about trying the nikel copper lines. supposed to be easy to work with.

[NW Task Force]

Hey guys, trying to locate the fitting circled in the picture provided. I basically need a "Y" block with 3 openings (3/8-24 IFF). I checked my local NAPA store and no go, or at least the guys there were puzzled. I basically am looking to replicate whats being shown in the picture. Any vendors/part numbers for this fitting? Thanks!

[1project2many]

The nickel copper (CuNiFer) lines are extremely easy to form and bend but you should be very careful in routing them to prevent any unwanted contact with other parts. They will chafe extremely quickly. In this area they also turn green quickly.

NW Task Force, that looks like an OE style GM fitting (it also looks like the UCA rear bolt is contacting the steering shaft!). This one may work though:
https://www.lefthanderchassis.com/v2...duct=259972059

Also might find something at Speedway motors.

[mknittle]

I thought there might be enough nickel to prevent that , but i guess not. maybe stainless after all all

I have read not to use a tubing cutter on stainless because of work hardening.

[OrrieG]

Originally Posted by NW Task Force

Hey guys, trying to locate the fitting circled in the picture provided. I basically need a "Y" block with 3 openings (3/8-24 IFF).

If you want it for looks, keep searching. For function a regular Tee fitting will work, fluid flow is minimal so an restriction at the 90 is not a factor. On mine each front line comes out of a separte port on the proportioning valve per the factory design. The rear has one line back to a tee that splits to each rear wheel cylinder.

[72Mountaineer]

If you're worried about looks, clearcoat them after they're installed. They'll stay new-looking for a LONG time!