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Brake lines 04 buick lesabre

I am a new ie tocars and selfteaching/youtubing/asking my way to learning a few things about my car

I am attempting to replace a blown brake line and a rusty brake line, both coming off my resevoir to what i assume is the master cylinder?
My question mainly is: it had quarter inch lines with bubble fittings, but none of my local parts stores seem able to help me, ive been told im gonna have to make such a thing and that seems like a huge pain, i am wondering i can avoid that by using 3/16" lines in some way, my primary concern is cost, i am on a prohibitively tight budget and just need my work vehicle to be able to stop again

Any help would be greatly appreciated

If you are new to repairing cars, brakes lines are not the place to start. Any parts store or the dealer can help you get the correct sized parts so if you are having trouble there is a mis communication somewhere. Please consider having the car towed to a shop and have them handle the brake lines. They do this all the time and will have you back on the road quickly and safely.

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Those ‘bubble’ fittings are commonly referred to as double flare fittings. The master cylinder is what the reservoir is sitting on, so these probably go to a proportioning valve or a modulator (I assume you have ABS brakes). While it’s possible to remove these and measure them and buy stock pieces of the same length, you would then need brake line wrenches and a bending tool at the minimum to replace them yourself. An online mega store might have them already formed as direct replacements. Then you would need to bleed your brake system, etc, etc. I would recommend against trying this on your own, though. If there’s one area of a car that MUST work properly, it would be the brakes. Beg, borrow some cash and take it to an independent brake shop.

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I have to agree with Steve - just about anything else is better to start your experience with cars. You mess this up, you not only risk killing yourself, you put others at risk. Not good.


GM parts lists the lines from the master cylinder to the ABS unit as 6mm (metric, slightly smaller than 1/4"), though the rest of the lines going to the wheels from the ABS are listed as 3/16" with metric-sized flare nuts (for 4.75mm tube, which is really close to 3/16"). Also, the original lines, discontinued from GM, have two sections of braided hose incorporated into them for flexibility. 1/4" or 6mm lines should not be replaced with a smaller size.

Bubble flares are sort of an unfinished double (or inverted) flare and are generally done on metric tubes and require metric dies for the flaring tool.

If air is introduced into the ABS unit when these lines are replaced, a GM scan tool may be required to perform an automated bleeding procedure of the ABS unit.

Agreeing with those above, I’d say this is not a job to be done by a beginner.


Alright, thanks for the input, suppose ill start making calls, i had read about the possibility of 6mm lines and its alot of information to absorb all at once, let a shop handle that and move on, got plenty of other things with this car to dink with lol

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Concur w/the advice to start learning diy’er auto repair on things like changing the oil and the oil filter; get all tooled up and that down pat before moving on to other stuff like the brakes. Popular Mechanics has a good general-purpose book titled something like “Complete Car Care Manual”, that’s a good place to start reading for a diy’er. Most public libraries around here anyway have it. There may be an article on how to make brake lines in there for reference.

One idea if you want to sort-of diy is to remove the part (tube with fittings on both ends) that’s leaking and take it to a shop and ask them if they can fabricate you a replacement with the same dimensions all around. Brake lines have to be made of the right materials and the fittings must be exactly the right kind for what they connect to. And they must be flared in a special way as mentioned above called a “double flare” which requires a special tool. Most of the better shops have that tool and the proper materials to make brake lines and know what to do so you end up with a reliable brake system.

My local inde parts store will make custom brake lines. The chain stores won’t though. So if you can find a local inde parts store, that’s another idea.

I have had customers buy lines and fittings to cobble together brake line repairs, and it makes me cringe. Even though I politely suggest a proper repair(e.g. “Using compression fittings on brake lines isn’t legal, just like it says right here on the package.”), they almost always go ahead with the purchase anyway. SMH :dizzy_face:

If you are on a budget, new to car repair, and not looking for a repair that will last forever, I would use flex line (like the NASCAR guys use) to replace the metal lines. I had a 2000 Accord that rusted out the brake lines and I had them replaced with flex line six years ago. The flex lines are still going strong and brakes are the least of that car’s problems. The cost was less than half of using metal lines and installation was much easier.