The Mini Mag. ..... Volume No.3 No.2.... 2001
  February 2001

Volume 3 Index. | Article Index.
HOME RESTORATION.


Everything You Wanted to Know About Brake Plumbing.
Part 2.

Teflon lines:
They may not have a place on your street car. For starters, the Teflon lines you make up at home don't have DOT approval, because they haven't been through the DOT approval process and you're not a certified manufacturer. Even the Teflon lines you can buy pre-built are probably not DOT approved (though there are a few coming onto the market) for the same certification reasons. The main reason for this lack of approval is that manufacturers of racing gear don't care to spend the money - they're building the hoses for racers. The next reason is that the DOT expected lifetime for such brake hoses is five years, and the prudent racer will replace his or her brake hoses every other season, just to be sure. (This is a good reason to make your own - then you can reuse the fittings and just buy new olives and hose.)

There are some concerns about using Teflon line in cold environments. Teflon hose and rate them to -40 degF. It may well be that the intended application for those lines is not subject to as much repeated deflection as the flex line snaking through your front suspension out to the caliper.

Other sealing methods: There is one other kind of sealing involved in braking systems, usually at caliper or cylinder entry and often when converting over from one kind of flaring system to another: a washer face at the top of a hole. This requires a crush washer of soft copper, aluminum, or in extreme cases, a Stat-O-Seal, which is a combination of O-ring and aluminum crush washer. To make this an effective seal, a precision machined surface is required around the drilling, exactly perpendicular to the axis of the threaded hole. If this is not there, you must use a bottom sealing fitting. Conversely, if the hole does not have a nicely formed drill point form at its bottom of the fitting will not reach the bottom, you must use a sealing washer (and, of course, provide the machined washer face for it to seal against). A neat trick is that copper crush washers can be reused - IF you anneal them. Place the washer in question on a brick and play your propane torch across it until it glows orange. Let it cool. It's now as soft as it was originally and will re-crush and seal perfectly.