Jim Smart
November 14, 2016

Unless you’re performing a concours restoration on your 1965-1978 Mustang, you will want to perform constructive modifications that make a vintage car safer and more enjoyable to drive. This approach to classic Mustangs—known as restomod—is the fine art of taking a popular American classic and improving it. You end up with great classic looks with modern performance to match.

One core issue with these older Mustangs has always been brake function and making it better. Classic Tube was the first at bat with preformed galvanized and stainless steel brake lines and flexible reinforced hoses for vintage Mustangs. Classic Tube has hit another homerun with StopFlex stainless reinforced brake hoses for older Mustangs. The company’s StopFlex brake hoses are extremely durable braided and wrapped stainless, and as a result, they are minimally flexible to give your braking system a firm pedal. What’s more, they are DOT Compliant for street use; have minimal volumetric expansion (firmer pedal); immediate response; not as soft as with other hoses; and corrosion resistant.

What makes these hoses superior to your Mustang’s original equipment is their construction. StopFlex brake hoses incorporate a special three-layer design for superior strength and virtually no expansion. According to Classic Tube’s Paul Fix, StopFlex begins with a tough Teflon PTFE core liner, then a stainless steel braid, and finally, a clear vinyl cover that will outlast any conventional brake hose. Conventional rubber brake hoses deliver a spongy brake pedal because these guys flex under hard braking. That is approximately 1,200psi when you romp on the brakes per Classic Tube. And because StopFlex has a strong core and stainless steel braided construction, you get a hard brake pedal and a crisp response.

When you combine StopFlex brake hoses with preformed lines and hardware from Classic Tube, you’re getting outstanding “Made in USA” quality to install on your classic Mustang. Here, we show you how to install StopFlex brake hoses on your classic Mustang.

01. This Ford Granada-style single-piston front disc brake fitting with two copper compression washers is typical of Mustang disc brakes from 1968-1978. Earlier 1965-1967 four-piston calipers have a straight-in brake hose connection sporting a single copper compression washer.

02. The brake hose banjo bolt is removed from the caliper using a 9/16-inch box-end wrench. You will want a catch pan or bleeder hose to capture brake fluid. If it has been a while since you’ve flushed and bled the brake’s hydraulic system, flush the system now. Brake hydraulic systems should be flushed and bled every two years when you perform engine-cooling system service.

03. The brake hardline is disconnected using a 3/8-inch line wrench. Take extra care not to get brake fluid on paint or undercoat, which permanently damage the paint, and remove the hose bracket with a 1/2-inch socket.

04. Check out these Stop Flex stainless braided and laminated brake hoses from Classic Tube. Classic Tube has its roots in classic Mustangs and vintage road racing.

05. Install the two copper washers included in the StopFlex kit, one on each side of the hose-to-caliper fitting. These are known as crush or compression washers because that’s exactly what they do. Never use anything but copper washers here, and always install new ones. Copper washers conform (crush) to the concentric rings in the caliper and brake hose banjo fitting to properly seal and contain brake hydraulic pressure.

06. Tighten the brake fitting banjo bolt to where the bolt feels like it’s seated firmly.

07. StopFlex stainless braided brake hoses look sharp and will virtually last the life of your Mustang. Once brakes are properly bled, your brake pedal should feel as hard as a rock.

08. Rear brake hose replacement is straightforward with two steel brake lines and the rear axle vent fitting. Lines are disconnected first using a 3/8-inch line wrench, and the vent fitting is removed using a 9/16-inch open-end wrench.

09. The brake hose is tied to the body at this bracket. The hard line is disconnected using a 3/8-inch line wrench, also called a tubing wrench.

10. Classic Tube StopFlex rear brake hose is installed at this body bracket, as shown, using the provided retaining clip. This clip can be challenging, so be patient.

11. The rear brake hose installation here at the body bracket is complete. When you tighten brake line fittings, tighten, then loosen. When you tighten the fitting again, go even tighter to seat the flared fitting. This reduces the chance of leakage.

12. Install the Classic Tube StopFlex hose at the rear axle, as shown, with the vent tube fitting first, then start the brake line fittings. Once you start the fittings, you’re free to seat the vent tube fitting and tighten the lines. As with the body line, seat the lines, loosen, and retighten firmly. This approach seats the flare.

13. The completed rear axle StopFlex hose installation looks good and will last the life of your Mustang.

14. The rear axle vent hose is connected like this. You may use a spring clamp, which makes for a clean installation, or install a worm gear clamp. Fuel injection hose clamps will also give your installation a professional look.

15. The rear axle vent hose joins the body here and the end of the hose is inserted into the central framerail. We used an Adel clamp in this location.

16. Four-piston brake calipers like we see on 1965-1967 Mustangs (and some of the aftermarket stock replacement disc brakes) have this single copper compression washer, instead of the two found from 1968-up.

17. When you install StopFlex hoses fore and aft, it is advised that you flush the brake hydraulic system. We’re bench bleeding the master cylinder as installed in the vehicle. All you have to do is add fluid to each reservoir and slowly depress the brake pedal until all air is purged. Mineral-based DOT 3 brake fluid will damage paint, even the tiniest droplet will lift paint. Be sure to cover all painted surfaces when adding fluid. Protect your Mustang’s paint finish inside and out.