[johnhawes]

Can anyone tell me the size of Mustang II brake lines, it looks to me like the front are 1/8" and the rear are 1/4". I am using a 1977 Mustang II master cylinder, front and rear brakes, and proportioning valve on a street rod and need to fabricate the brake lines from the master cylinder to the front and rear brake hose connectons.
Thanks
John Hawes

[powerrodsmike]

1/8 brake line is unheard of, and 1/4" is ok, but not necessary.
Remember that tube size is measured from the outside of the tube.

I use 3/16 line all the way around, and get the correct tube nut to adapt the line to whatever the port size is.

You can size the port sizes by usung a fine thread bolt,

3/16" tube uses a 3/8-24 thread, 1/4" uses a 7/16"-20 or 7/16-24. Some ports in master cylinders use even larger thread sizes, such as 1/2-20 or 9/16-18.

You local napa store should have a good selection of tube nuts and master cylinder tube nuts...if not, Speedway motors has a bunch of them .

Hope this helps,
Mikey

[kleen56]

Not sure why you have two sizes of brake line? Most vehicles use a 3/16" line for brake line. When your making new lines, make sure the ends are double flared and not single flared. Helps to eliminate leaks.

[powerrodsmike]

Originally Posted by kleen56

Not sure why you have two sizes of brake line? Most vehicles use a 3/16" line for brake line. When your making new lines, make sure the ends are double flared and not single flared. Helps to eliminate leaks.

Many stock vehicles use 1/4' in a drum brake rear for fast brake shoe retraction. And 3/16 in the front..

Many drum brake cars have 1/4" all around.
Later, mikey

[johnhawes]

It seems that I was confused by the different port sizes on the master cylinder and proportioning valve. Powerrodsmike pointed out that 3/16" line works fine when the correct sized tube nut to adapt to the port size is used.
Thanks guys---
John

[johnhawes]

Thanks Mikey, I have drum brakes on the rear so if I use 3/16" on the front disks, and 1/4" on the rear drums I should be OK. I have a double flaring set- up so all I need are the correct length 1/4" and 3/16" lines and should be good to go.
Thanks again
John

[kleen56]

John, I'm running a Corvette disc/disc master cylinder on my vehicle. The outlets on it are different, as in the front looks like 1/4" and the rear 3/16". I'm using disc brakes on the front and rear, I plumbed the brake lines with 3/16" line to both the front and rear brakes. I simply used an adapter at the MC for the line connection. My brakes work fine with that combination. I am running a Wilwood proprotioning valve to the rear brakes only. My master is mounted to the firewall, so I didn't need the residual valves in the line. If your mounting the MC on the frame, you'll need the 2lb and 10lb residual valves in the lines. Hope this helps.

[johnhawes]

Thanks kleen56 it gets right to the point and helps a lot.
Thanks
John