Need some help with vacum assisted brakes

[hillbean]

Hey everyone thanks to all of your great write ups i started my engine/trans/ps/pb swap and am about to wrap it up just need a lil help from ya all. I pulled the MC/Booster/Prop valve from a 73 Chevy c10 truck and then after deployments and some other stuff i lost the brake lines. Does anyone know what size lines and fittings go from the master cylinder to the prop valve and from the prop valve to the rear brakes. I can post a picture when i get a chance. Ive tried looking everywhere but cant find anything any help is much appreciated.

[vince1]

You did say any help so even if it isn't I'll try a bit. I used a 67 master cylinder so don't know if it is the same as yours. Pulled some lines from a junk yard, closest to firewall for front brakes were 1/4", and furthest forward were 3/16" to back brakes that I stepped up to 1/4. I don't know the fitting sizes or if 3/16 or 1/4 was even relevant as you could probably use either size in an appropriate fitting.

You might also try and take your master cylinder and wander off to a car parts shop like O'reilly's? and check out their lines and fittings.

[Captainfab]

Not all master cylinders are the same in regards to which port is for the front brakes and which port is for the rear brakes. The easiest way to determine which is which, is by the size of the threads in the ports. The 3/16" line is for the front brakes and the 1/4" line is for the rear brakes. The prop valve will have 2 ports on one end for the two 3/16" lines that go to each front caliper. The opposite end will have one port for the 1/4" line that goes to the rear brake hose that drops down to the differential. The two ports on the side of the prop valve are the in ports from the master cylinder.

[hillbean]

Yeah i have a 3/16 line for the front port and 1/4 line for the rear port the standard fittings are to small for the M/C I think im just gonna grab an adapter and do it that way i was just wondering if there was a specific line size i needed and it sound like I have them. Thanks for the help guys

[Captainfab]

The master cylinder will have threads that are larger than a typical tube nut. In looking up a '73 C10 master cylinder the front brakes have a 9/16"-18 thread and the rear brakes have a 1/2"-20 thread.

[61K10]

summit racing sells tube nuts for the master, but you have to re-flair the ends of course.

[hillbean]

thanks for the help guys i got it figured out just had to spend an hour at the parts store looking for the fitting for the rear brakes