Rubber Brake Line Collapse - What Causes This?

 Light, simple, safe. We obsess over those three words. But even the humble parts—like rubber brake hoses—age out. A recent case on a very low-mile ’05 Elise reminded me how quietly time can catch up and change how a car stops.  Disaster struck this car when the rear driver side caliper locked up.  Fortunately the owner was able to nurse the car home safely and have it towed to us for repair.  

Symptoms were odd: only one rear corner dragged; eventually it freed itself. Fluid was old but in OK condition. The car still had its original OEM rubber brake lines. My working theory: internal hose aging created a one-way restriction—easy pressure in, slow/no return—so the caliper stayed applied longer than it should resulting in a smokey brake and a fully locked up corner!

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How OEM Rubber Brake Hoses Are Built

An Elise OEM hose looks simple, but it’s a multi-layer composite that works hard every time you hit the middle pedal.

• Inner liner (EPDM): Carries brake fluid; resists heat/chemicals.
• Reinforcement braid: Limits expansion under pressure.
• Outer jacket: Protects from heat, ozone, abrasion.

Nothing exotic here—and that’s the point. It’s good, durable, serviceable… but it still ages and why we wrote a previous: BLOG

What Age Does to Brake Hoses

Outer cracking is easy to spot. The sneaky failure is inside the hose—where you can’t see it.

Failure mode	How it develops	Real-world symptoms
Internal collapse / check-valve effect	Inner liner hardens, micro-cracks, or delaminates; a flap or swelling narrows the bore.	One corner drags, brakes feel uneven, wheel runs hot; caliper may “release itself” later.
Reinforcement fatigue	Braid loses stiffness after years of heat cycles and moisture.	Softer pedal, more travel, vague response under repeated stops.
Outer jacket degradation	UV, ozone, road spray, or heat near rotors/exhaust.	Visible cracking, surface bubbling, damaged sections near fittings.
Fluid & moisture interaction	Old DOT 4 absorbs water; moisture + time accelerates internal deterioration.	Lower boiling point, discoloration, more fade when hot.

Yes, even Exiges...

Why only one side? Hoses age unevenly: routing, heat (exhaust proximity), flex cycles, and tiny manufacturing variances mean one line can fail years before its twin.  See the picture below of the Elise that failed and note the sourcs of heat.

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OEM vs Upgrade Options

• Fresh OEM rubber: Restores factory feel; perfectly fine for road cars.

• InoKinetic braided / stainless kit: Improved pedal consistency, durability, and peace of mind. Designed specifically for Elise/Exige fitment.  Our QWKbleed SS Lines are worth a look - see them: HERE

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Elise Brake Hose Refresh: Quick Checklist

• Replace all four hoses together. Don’t chase symptoms one corner at a time.
• Flush with fresh DOT 4. Bleed thoroughly; check for equal flow at each corner.  We like: Motul
• Inspect calipers. Verify pistons, seals, and slide pins; address any asymmetry you find.
• Route & secure. Ensure full droop/compression clearance, no twist, no chafe.
• Road-test & heat-cycle. A/B stops, then re-check for drag or wheel-to-wheel temperature differences
• Set an interval. For street cars: consider 10–15 years as a practical horizon; sooner for heavy track use.

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Bottom Line

Yes, even new Emiras will eventually succumb...

Rubber brake lines don’t ask for attention—until they do. If your Elise or Exige is still on originals, consider this your nudge. Replace the hoses, flush the fluid, verify the calipers, and get back to what the car was built for: precise, confidence-inspiring braking that lets you carry speed where it counts. 

Rubber Brake Line Failures

 It seems sometimes, when it rains, it pours.  On one day last week, we had two clients come in with failed OEM rubber brake lines.  One of these cars, a '06, had <35k miles and the other, a '05, had 250k miles!  One of the cars that failed had a very slow leak and the owner was not paying attention to the reservoir as it was getting drained.  The other car, with lower mileage, had a massive failure that kept the owner from bringing the car to us.

These are the first two failures that I had heard about.  Early Elises have lines that are now nearly 20years old.  Rubber does not last forever and mileage is not necessarily a good measure of when to change them.   I'm expecting to hear about more failures, in the coming weeks and months unless owners take preventative measures.

So what can be done?  Replace the lines.  You can either order new factory rubber lines or upgrade to our Stainless Steel lines.  Our lines will most likely, last the lifetime of the vehicle.  All of our lines are DOT-spec and encased in a polyurethan housing so that stainless does not saw through any adjacent parts.  

Replacing your lines is not overly hard but varies based on which model you have.  The Elise front lines can be done without removing the clam - while the Exige requires front clam removal.  The rear lines, on both cars, can be done without clam removal.

Our brake line solutions come in a couple of different flavors:

QWKbleed Lines: We recommend this kit for the front calipers as they allow you to bleed both sides of the caliper properly.  The stock caliper uses a budget minded approach with the lines entering a port that would normally feature a bleed nipple.  Our innovative QWKbleed lines make that port into a bleeder so you can get out all of the air bubbles during the bleeding process.

SS Lines:  These are a simple and cost effective upgrade.  If you want to save some money and get a solution that works, this is the one.  We also sell them in a 2 pack for the rears: HERE

For street cars, we recommend bleeding your brake fluid every year and flushing every 2-3 years.  Track guys should be bleeding before every event and flushing once a year.  Our Motul RBF600 has been a great solution for road and track.

If your car still has the stock rubber lines, regardless of mileage, I would stongly suggest replacing them ASAP.  Have a look at our offerings or give us a call if you have any questions.

111RS #3 Build: Suspension, Brakes & More

We are starting to bolt on all the four corners of the 111RS now.  This includes the Refreshed Wishbones with MONOballs and Refreshed Uprights with new Hub Bearings.  New hardware is getting installed as the old bits are looking tired.  We added new 12.9 hardware to the refreshed calipers as well.  FASTarms are also a must have for this build.

This build is getting the DNA Front & Rear Swaybar kit as we've become big fans.  We love the ability to run much softer spring rates thanks to roll stiffness being managed by the sways.  The added compliance on rough roads and tracks is remarkable.  We will install the DNA Rear Toe link brace as well.  This is the first 111RS that has received this upgrade - it almost feels sacrilegious considering we make excellent braces ourselves!

We had a set of Nitron 46mm Singles that we had rebuilt sitting on our shelves.  We also have 350# and 500# springs that are reasonably light.  Usually we go lighter still with the DNA sways but we would test these rates on this car.  Generally we had run Nitrons in the past with 450# spring and up.  The lighter rates that we are running compare with what came on their Street Series dampers.  Since Nitron are building a Tech Center in our town, we thought it would be good to have a set on this car to test and tweak.  If you have not seen our video interviewing the Owner of Nitron, Guy Evans, please watch it: HERE

ULTRAdiscs are simply the best rotors for these cars with a 10lb unsprung weight savings.  We have paired them with G-loc R10 pads.  I like my cars to brake more aggressively than stock and this combo does not disappoint.  They are killer in the canyons and work fine on track.  Our QWKbleed lines are being fitted.  BULLETstuds were added as well.

We've deleted the passenger oil cooler - of course!