Brake Flex Line Size 3AN or 4AN

[jbow03]

I'd like to make a flexible connection from the firewall to a proportioning valve for my brake setup. Trying to decide what size hose & fitting types to use, my thoughts below:

1. What size lines should be used? I was going to use -4 AN PFTE 6000 line from Fragola to try to match the .187" ID of the normal 3/16" brakes. Then, I checked the size of flex from the factory used for the connection to the calipers and it looks like it's -3 AN from what I see on Wilwoods website.
2. What fittings are acceptable in a brake application? I like the selection options of Fragola's aluminum fittings, but does steel need to be used in a brake application. There seems to be less steel fittings out there as well as colors, but I think I could make it work if it all had to be steel.

Thanks for any input!

192056

192055

[F500guy]

Generally -3AN is for the 3/16 brake line and Aluminum is not recommended on brake lines due to the potential pressure involved. Check some race supply shops, but I think Stainless is the best bet and most available.
https://www.pegasusautoracing.com//group.asp?GroupID=PTFEHOSE

[rich grsc]

AN3, brakes are about pressure, not volume.

[phils88gt]

The nomenclature of AN fittings is based on the fluid ID of the tube. -3 AN is three sixteenths of an inch. sometimes hose can have varying diameters but I would not stress that here. -3 is acceptable for what you are doing. Some large vehicles have 1/4 brake line but they need to move larger volumes of fluid to much larger caliper pison bores than would be used in a car. ( Yes I am aware ford does occasionally use 1/4 on simular families of cars like the thunderbird so it's parts can't be mixed up with something like a mustang. )

Phil