BRAKE LINE REPLACEMENT: SHOULD I REPLACE THE FITTINGS AS WELL?
                     BRAKE LINE REPLACEMENT: SHOULD I REPLACE 
THE FITTINGS AS WELL?
Mark Sanford
Writer at Brake System
University providing advice, reviews and information on 
brake system components including 
brake line repair tips at brake system university /
brake line repair kit reviews at break system university
There are three ways to approach a brake line replacement job: buy a 
direct replacement brake line, use a pre-flared brake line, or invest in a 
brake line kit and make the whole thing yourself. With the first two, 
reusing the old fittings isn’t an option: the line comes with new ones. Use a 
brake line kit to make your own from scratch though, and now you have 
the option to reuse those old fittings. Here are some points to consider.
REASONS FOR REPLACING BRAKE LINES
Routed along the underside of your vehicle, brake lines are exposed to salt, 
dirt, and whatever deicing chemicals are used in your part of the world. 
Unless your ride is blessed with stainless steel, the lines are going to 
corrode. Nickel copper and poly-vinyl fluoride (PVF) lines will last longer 
than steel, but their life is still finite.
Brake lines can also corrode from the inside out. This happens if you don’t 
change the brake fluid at the prescribed intervals, especially if it’s 
hygroscopic (water-absorbing).
Other reasons for replacing brake lines are because they got damaged 
somehow, because you’re modifying the vehicle, or because the end 
fittings or flares have been damaged.
BRAKE FITTINGS
Rigid brake lines are flared out at the ends. A flare nut mounted on the line screws 
into a mounting block, trapping and compressing the flare in the process. This is 
what seals against brake line pressures as high as 2,000 psi.
Flexible brake lines, or hoses, are often connected with banjo fittings. These are 
two-piece fittings where a hollow bolt passes through the center of a ring-shaped 
union fitted to the end of the hose. Copper crush washers sit against each face of 
the ring to create a seal.
REUSE OR REPLACE THE FITTINGS?
If you’re working with a brake line kit you have the option of reusing fittings from 
the lines you’ve just removed. As a general rule, don’t. Here’s why.
• Fittings taken off a vehicle could have cracks or corrosion not visible to the eye
• Threads may be damaged
• Hexagonal faces could have been rounded
Distorted or misshaped threads will raise the torque needed for fastening, letting 
you think they are tight when they’re not. If hex sides are rounded or damaged 
from being clamped in grips, a flare nut wrench could slip and do more damage. If 
you get the fitting done up tight it may never come undone again!
With a banjo fitting, while you can reuse the union it’s best to replace both the 
crush washers and the bolt. The washers act as gaskets and once used they’ve 
deformed and may not work as well next time. Plus, the bolt stretches when 
tightened, and if it’s been over-torqued previously there’s a risk of it snapping.
THE BOTTOM LINE
If you’re going to the effort of replacing a brake line, don’t cheap out on fittings. It 
could lead to premature failure, and who wants to risk that in the braking system?
About Brake System U
Brake System University is a micro site giving advice, reviews, and technical 
information on various brake system components like brake lines, brake 
line kits, and ABS sensors. Brake System University connects you to high 
quality, genuine brake system replacement parts including  replacement 
brake lines, replacement ABS sensors, replacement brake line kits that 
have been tested and reviewed by experts. If you want to replace any 
component of your brake system, then this 
site(https://brakesystems.autopartsu.com/) will helps you in choosing the 
right component. Brake System University connects you to trusted reviews 
and referrals to help you easily make a purchase decision.