How do you fix a leaking metal brake line?
A leaking brake line means you need to replace the damaged metal line section and properly bleed the brake system afterward. Getting air trapped in the master cylinder or failing to clear blockages will prevent fluid from reaching the calipers, stopping you from restoring safe brake pressure.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1Replacing the damaged lines with copper or copper-nickel linesDid this help you?
- 2Running new lines to the flex lineDid this help you?
- 3Reverse bleeding using a hand pumpDid this help you?
- 4Shutting off front or rear and bleedingDid this help you?
- 5Investing in a pressure-based bleederDid this help you?
- 6Doing a gravity bleed or using a vacuum extractorDid this help you?
- 7Cut off the end and redo the flare if there is enough slackDid this help you?
- 8Buy premade lines at the auto parts store and bend them to fitDid this help you?
- 9Use a copper flare gasket to try to seal the connectionDid this help you?
- 10Checking and ensuring copper washers are placed on each side of the banjo boltDid this help you?
- 11trying to bend the lines back into shapeDid this help you?
- 12applying gasket maker to stop the leakDid this help you?
- 13Bleeding the master cylinder firstDid this help you?
- 14Using a vacuum pump or a helper for manual pressure bleedingDid this help you?
- 15Gravity bleeding the linesDid this help you?
- 16refitting the banjo boltDid this help you?
- 17checking for debrisDid this help you?
- 18tightening the boltDid this help you?
- 19checking for old copper washers stuck on the line or boltDid this help you?
- 20ensuring crush washers are present on both sides of the banjo fittingDid this help you?
- 21Replacing the entire brake line properlyDid this help you?
- 22Demanding a refund or demanding the shop redo the repair correctlyDid this help you?
- 23Replacing the entire length of metal brake pipe with copper instead of splicing.Did this help you?
- 24Cutting the hard line and using a mini tubing cutter, then using a tube union and NiCopp replacement line with a new flexible hose.Did this help you?
- 25Replacing the whole line from the ABS pump back.Did this help you?
- 26Making a new hard tube and brazing the fittings.Did this help you?
- 27Replace caliper and bleed brakesDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Anyway, I got all the new lines in, went to bleed the brakes and no fluid was coming through the lines.”source ↗
“My 2005 Honda Civic EU 1.6L, 5dr recently lost braking power. The rear pipes are completely rusted (leaking on the other pipe), and I know you can splice on new copper pipes, but on my brake pipes (not hoses), there's a hard plastic covering that's pretty hard to cut through that's along the whole pipe.”source ↗
“My issue is, the hard brake line going from the brake master cylinder to the hard line feed for the front brakes isn’t lining up correctly because long story short they got bent out of shape.”source ↗
“I spent an hour trying to bent them back to line up without the brake fluid leaking out of them when pressing the brake pedal and it still leaks the fluid out.”source ↗
“I’m on a time crunch with access to nothing and 30 minutes away from the nearest anybody”source ↗
“hey guys im new to doing my own repairs and want to fix this my self, basically where the metal brake line tubing meets the rubber tubing on the right rear wheel its so rusted that there not even a nut there anymore”source ↗
“as i was cleanign it with a flat head screw driver it broke apart because it was so rusty.”source ↗
“So ya please let me know anything that will help and if these instructions are accurate or not thankyou guys”source ↗
“what is the cheapest way to fix”source ↗
“It's gushing brake fluid and the pedal is going to the floor. No, it does not work.”source ↗
“So it’s definitely a bad caliper ? Because it still works. That has never been”source ↗
“I recently replaced my lines and I can’t get one of 3 flared unions to stop leaking slowly.”source ↗
“I have a 99 GMC Sonoma. This is a picture of it's break line leak, on one side of this connector is a ribbed metal break line and on the other side is a smooth metal break line.”source ↗
“What should be my plan of attack now that i have located the leak.”source ↗
“while bleeding the brakes, we accidentally ran the master cylinder dry.”source ↗
“when we tried bleeding the brakes, the fluid did not appear to be moving, and no brake fluid came out of any of the four calipers.”source ↗
“we tried bleeding it for like two hours nothing coming out”source ↗
“I disconnected the brake line from the caliper while changing my brakes(which I now know is completely unnecessary if you’re not replacing the caliper) and the line started leaking brake fluid.”source ↗
“So, I went to reconnect it and it kept leaking after replacing the screw in the caliper. I think I over tightened the screw when replacing it, or it was already damaged and removing the screw just worsened that.”source ↗
“What can I do to fix this? I know I’m going to have to bleed the brakes once I stop the leak but I can’t get it to stop. Should I replace the caliper?”source ↗
“I was trying to start bleeding the brakes but the brake fluid is spurting out of the brake line instead.”source ↗
“I've tried refitting the banjo bolt and I've checked for debris and I've tightened it as much as i can but I keep getting the same results.”source ↗
“It appears to be coming from where it connects to the caliper, i made sure the old washers were off and i do have them on either side, I'm thinking its something with the washer connecting to the caliper but no matter how I fit it or how much I tighten I get the same exact results”source ↗
“Using compression fittings on brake lines is unsafe and illegal in many places...they are not designed for the amount of hydrulic pressure that brakes can push.”source ↗
“I check the underside where I saw the leaking fluid and low and behold I see a brand new compression fitting, albeit a steel one but still.”source ↗
Where this came up
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