Basic question on brake lines

[focusedontheprize]

After I get the parking brake assembled this weekend, I am going to be able to start running the brake line. This is my first time doing this so I have a few questions:

1949 Chevy truck
Front brakes: Classic Performance Part's 5 lug 4 3/4 disc conversion
Rear brakes: 1997 Ford Explorer 8.8 axle and OEM brakes

Brake booster is apart of CPP's 5 lug conversion.

I called CPP yesterday and was told they run a 3/8 fitting on the proportioning value for the front brakes (for both sides, 2 separate lines to each front corner) and a 9/16 fitting for the rear brakes.

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With that being said I am running 3/16 line, so I was told inside of running adapters to size down to 3/16 line, I could just put a 9/16 flair nut on the 3/16 line (again I am flaring my own lines) and that would clean everything up. I would could do the same for the 3/8 fittings in the front brakes.

So my question is, would this work? I assumed as the size increased (to 9/16), the hole in the flair nut would also get larger so it would be bigger than the 3/16 line.

Any help would be a huge help. Thanks.

[Speedbumpauto]

Without looking at your hardware or talking to the CPP folks, I think there is confusion between tubing size and wrench size. The wrench size for the standard 3/16 line is 3/8. I have not seen a 9/16 flare nut for 3/16 but have seen factory heavy duty 1/2 wrench size 3/16 flare nuts. If the 9/16 wrench size is correct, I believe the rear line is 1/4 tube. I have seen hd flare nuts for 1/4 tube in 9/16 wrench size used by the factory. 1/4 tube would be an OK choice to run to the rear for both brakes if you can get the correct flexible line from the frame to the rear end. Then you could drop down to 3/16 on the individual lines to each side. Neat and simple. If it was me, I'd take my proportioning valve down to the local auto parts store and try fittings until I found the correct combo. Bet it will be simple. Hope all the fraction sizes make sense.

[focusedontheprize]

Originally Posted by Speedbumpauto

Without looking at your hardware or talking to the CPP folks, I think there is confusion between tubing size and wrench size. The wrench size for the standard 3/16 line is 3/8. I have not seen a 9/16 flare nut for 3/16 but have seen factory heavy duty 1/2 wrench size 3/16 flare nuts. If the 9/16 wrench size is correct, I believe the rear line is 1/4 tube. I have seen hd flare nuts for 1/4 tube in 9/16 wrench size used by the factory. 1/4 tube would be an OK choice to run to the rear for both brakes if you can get the correct flexible line from the frame to the rear end. Then you could drop down to 3/16 on the individual lines to each side. Neat and simple. If it was me, I'd take my proportioning valve down to the local auto parts store and try fittings until I found the correct combo. Bet it will be simple. Hope all the fraction sizes make sense.

Speed -

Thanks for the response. I guess I was trying to evade an adapter, but no matter what I think I have to run one. I was searching the Internet and found Classic Trucks ran an article on plumbing their MC on the firewall (http://www.classictrucks.com/tech/11...ter/index.html).

In this picture:


and this one



you can see an adapter (bare steel color) that then runs into the 3/16 line (probably with a 3/8 flair nut), so I will need to locate one of those adapters at my hardware store.