How to Make Brake Lines: Master Cylinder to Caliper
There are good reasons to make your own brake lines rather than buy them off the shelf: a perfect fit on a modified car, exact lengths for a custom setup, or upgrading tired rubber hoses to braided. This guide covers how to make brake lines that run the whole way from the master cylinder to the calipers, what parts you need, and how to do it safely.
This is a job for someone comfortable with brake work, fittings and bleeding. If any of that’s outside your wheelhouse, we can make the lines up for you in store, ready for you or your mechanic to fit.
One thing to know up front: if your car is road-going, a road-legal braided line needs to be TUV approved, which a line you’ve made yourself won’t be. So the “make-your-own” route in this guide is aimed at competition and track cars. For a road car, a TUV-approved kit like the Goodridge upgrade lines is the way to stay legal, and we can supply those.
How a Brake Circuit Runs, Master Cylinder to Caliper
The job of the circuit is simple: turn pressure at the pedal into clamping force at the caliper, through fluid that can’t compress. Press the pedal, the master cylinder pushes fluid through the lines, and that pressure squeezes the pads onto the disc.
Running out from the master cylinder, the fluid travels along hard line or flexible braided pipe fixed to the chassis for the long straight runs, then switches to flexible line at each corner where the suspension and steering move. Along the way there may be unions, tees and, on many cars, a bias or balance setup that splits pressure between front and rear. The flexible line makes the final connection to the caliper, which moves with the wheel.
Hard Line vs Braided Flexible Line
Hard line is the rigid tube that runs along the chassis and bulkhead. It’s fixed in place, it’s protected, and it’s used anywhere the line doesn’t need to move. For brake use it must be proper brake-grade tube, we only recommend using stainless steel.
Flexible line is the braided hose used at each corner, where the caliper moves with the suspension and a rigid tube would snap. This is where a braided upgrade earns its place: a braided stainless hose flexes far less under pressure than an old rubber one, so more of your pedal effort reaches the caliper, giving a firmer pedal. Flexible pipe can also be used throughout the complete car in place of hardline pipe as it is easier to retrofit and manage.
The Parts You Need
Each part maps to a product type, so this doubles as a shopping list.
|
Part |
What it Does |
Where it’s Used |
|
The flexible line that carries pressure to the caliper and flexes with the suspension |
At each corner, between hard line and caliper |
|
|
Rigid brake-grade tube for the fixed runs, with the correct nuts for your fittings |
Along the chassis and bulkhead |
|
|
Terminate each braided hose, matched to the hose type |
Both ends of every flexible line |
|
|
Join lines, split the circuit front to rear, and adapt between thread types |
Throughout the circuit |
|
|
Bulkhead fittings |
Pass a line cleanly through a panel instead of a bare drilled hole |
Anywhere a line crosses a panel |
One thing worth doing before you flare any hard line: slide the tube nut on first, since you can’t add it once the flare is formed.
Choosing Your Brake Hose
For the flexible sections, braided hose is the upgrade worth making. A standard rubber brake hose swells slightly under pressure, and that flex is what gives a soft, spongy pedal. A braided line replaces that flex with a stainless outer braid over a low-expansion inner, so the pedal firms up and more effort reaches the caliper.
For the inner, PTFE is the standard choice for brakes. In the Goodridge range we stock, the 600 series PTFE hose is the one built for brake and clutch lines, and its fittings are reusable, so a line can be rebuilt rather than scrapped if you change a fitting or shorten a run. As Ireland’s only official Goodridge G-Tech centre, we can also build these to length in store, if you’d rather not make your own, crimped and pressure tested to Goodridge’s exacting standards.
Making Up the Lines
This isn’t a torque-by-torque walkthrough, since the exact figures depend on your fittings and car, but these are the principles that keep the job safe.
- Plan and measure first. Route each line in your head, or with a length of wire, before you cut anything. Keep runs clear of heat, the exhaust and anything that moves, and avoid sharp bends, which kink the tube and restrict flow. Measure with a little allowance, but don’t leave loops of hose that can snag.
- For hard line, deburr the cut end before flaring, and always slide the tube nut on first. The flare itself must match your fittings: a double flare and a bubble (DIN) flare are different, and the wrong one won’t seal. Use a proper flaring tool and a tube bender rather than forcing bends by hand, and it’s worth practising a flare on an offcut before you commit to the real line. A bad flare is the most common cause of a brake line leak.
- For braided flexible line, build each hose with the correct ends for the hose type and follow the assembly method for your fittings. Our guide to assembling Goodridge 600 series fittings covers the reusable fitting process step by step.
- Where a line passes through a panel, use a bulkhead fitting, and support every line properly along its length so nothing hangs off a fitting or rubs through over time.
Bleeding and Pressure Testing
With brakes, this stage is not optional and not something you rush. Air in the system or a weeping union means the brakes don’t work properly, full stop.
Fill the master cylinder with the correct fresh brake fluid, then bleed the system thoroughly to get all the air out, working to the sequence for your car. Check every union and flare under pressure for any weep, and do not accept a slight seep as something that’ll settle, it won’t; and a brake leak only gets worse. Before the car moves, confirm you have a firm, high pedal that holds steady pressure. A pedal that sinks means air or a leak still in the system.
Test gently at low speed before any real use, and recheck every connection after the first proper drive, since fittings can bed in and loosen slightly.
Road and Competition Rules
Brake lines sit a little differently with the rules depending on whether the car is used on the road or in competition, so it’s worth knowing where you stand.
For a competition car, braided lines are widely used and generally aren’t restricted, but always check your championship’s regulations before building, since requirements can differ between series
For road use, we recommend using Goodridge OEM replacement brake lines which are TUV, DOT, ADR and ISO approved.
Wrapping Up
Making your own brake lines comes down to getting the fundamentals right: the correct tube and hose for each section, flares and fittings, clean routing away from heat and movement, and thorough bleeding and pressure testing before the car turns a wheel. Get those right and you’ve got a circuit you can trust.
If you’re building a brake setup, browse the brake hose, fittings and adaptors range at Race and Rally, or get in touch and we’ll help you spec the lines, fittings and hose your car needs.
Frequently Asked Questions
Are braided brake lines better than rubber?
For feel, yes. A braided line flexes far less than rubber under pressure, so the pedal is firmer and more responsive. The braid also protects the hose against abrasion and corrosion.
Do braided brake lines pass the MOT?
Yes, as long as they’re TUV approved. A TUV-approved braided line, like the Goodridge upgrade kits, is accepted for road use. A braided line you’ve custom made yourself won’t carry that approval, so for a road car the approved kit is the route to go. Goodridge supply TUV-approved kits for most vehicles, so get in touch and we’ll sort the right one.
Can you get braided brake lines in different colours?
Yes, Goodridges stainless steel braided brake hose is available with protective PVC Covering, available in Clear, Black, Carbon Effect, White, Blue or Red. Along with colour, this PVC coating adds a protective factor to prevent stainless braid rubbing against your painted chassis and also protection against electrical cables.