Brake line replacement. How Screwed am I?

2004 C4S Replacing the flex brake lines at each corner. Should be easy, right? Front Driver fought me, ended up having to replace the hard-line from the caliper to the soft line. Whatever, $20. Front Passenger has been a disaster. Caliper end was completely fused, so ordered another short hard-line to Caliper. No big deal. However, the body-side hard-line is also completely stuck. I've hit it with penetrant for a week. Hit it with a torch several times before trying to loosen. Early on, I went ahead and bought the $50 Snap-On line wrench, as online tests show they can apply more torque before slipping. Nothing. Fitting won't budge. Wrench slipped, and has started to strip the head. Fitting on the left. The wrench has already started to slip on the fitting. So. How screwed am I? I can buy the body side line. It is so circuitous! Is there any way to replace that without dropping the entire front subframe and front diff, maybe even the steering rack?? Ugh. Where does it go? I think to the other side of the bulkhead here: Is that correct? Is there some other loosening method, or shortcut, or intermediate fitting, or something to save me here? Thanks!!

I'd opt for cutting the body-side brake line at a suitable position and join a new piece of pipe with it. No need to replace the whole line imho.

The brake line requires the removal of the gas tank so u probably want to avoid that. U should be able to cut the line and reflair with a new fitting.

Thanks. I hate that it's that hard to replace the whole line. But I"m glad it's hard enough that I'm not really considering it. Any easier, and I would want to do the full thing! And I really don't want to get into that! I'll see if there is enough space, flex, and good line to just cut it back a tiny bit and replace the end flare. A splice will be plan B. So I think our lines are DIN 4.75mm bubble flair with a M10x1.0 fitting. Is that correct?

Sorry u dont have the line specs. Its common practice to splice or re-flair so dont harp too much of the non-originalality of the repair.

Some of the hard brake lines are just ridiculous. I had to replace the rear passenger side line that crosses from the drivers side below the door over the transmission to the passenger side rear wheel� Talk about a bitch! Not only was the line super expensive, it was almost impossible to install. In hindsight I should have cut and spliced� you live, you learn�

I just did a couple of brake line fixes on my 2000 where they were rusting out, etc. The Porsches use a European bubble flare and while I could buy sections with this style flare to replace bad sections you have to flare the old lines that you are connecting them to. And use unions for bubble flares which are easy to find. But for flaring the old lines making bubble flares was frustrating. The tools to do this can be very expensive. I tried using the tools from the rental programs at Advance Auto and AutoZone but while they would do decent double flares they would not do bubble flares. I bought another flaring tool that was supposed to do a double flare or a bubble flare but it would not do a bubble flare and quickly broke. I ordered a Cal-Van flaring tool on Amazon That specifically said bubble flares but they somehow doubled up on the bubbles. When I talked to the manufacturer and sent them pictures, they did not understand how it was happening, offered to send replacement parts but I just returned it. I finally went to a Harbor Freight and bought their Maddox Deluxe Flaring tool, it was only $69.00 and it worked every time and was not hard to get to the lines I needed to flare. So save yourself some time and get that one. And then use the copper nickle lines as the are easy to bend and easier to flare. Good luck!

I think I'm definitely glad to pursue other options, rather than taking the entire front end apart. Regarding the fittings, I realized I can look at one. This is the new short front hardline that goes to the Caliper. I know the threads are M10 x 1.0. I'm pretty sure based on pictures that that is a DIN bubble flare. But advice appreciated. If I do the splice, I know it won't matter what type I use, but I just think, given that this will be a non-standard fix/splice, that I would like to do it as factory consistent as possible. Front Passenger hard-line (soft-line to Caliper) Assuming that's correct, I've ordered some stainless DIN fittings, stainless line, and a splice connector. Also one of the smaller flare tools. I do love an excuse to buy a new tool and learn a new skill.

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Thanks!! I ordered and posted my plan above before I saw this. Since I bought 25ft of line too (only need max 12 in), I'll make sure to just test my tool, and my skill, on the bench (a lot), before trying to do the side on the car! This is what I bought, thinking it might be easier for a confined space, but we'll see. The HF one looks like a good deal. https://www.amazon.com/dp/B0BRNYRWG1

+1what Dharn said copper nickel line is more forgiving (softer) easier to flare than stainless.Stainless likes to have properly squared up and prepped end.Continued success with project.

This is definitely a useful thread for me. I bought braided lines for m 996. Fronts went on fine, but gave up on rears because I could not break looks the flex line and the supply hard line. Considered replacing the whole line, but now glad I did not pursue. I thought about this approach, but was not sure about specs for line and connectors. This helps. Thanks.

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So the only part I'll have to do on the car is the end of the factory line. So if that's NiCop, I'm glad to know that will be easier. Any new segment from the splice to the soft-line, I can make on my bench before installing. So I should be able to make good fittings with the stainless. But I will post here and let you know if I give up crying and end up ordering some Nickel-Copper and/or new tools.

Factory lines are coated steel. You are correct, M10x1.0 bubble flare. The line is 3/16" or 4.75mm (interchangeable). You'll need to cut and reflare the factory line. You may get away with not extending it if you are clever and do some reforming. You may want to get an M10 bubble flare coupler in case you end up needing to extend the line. I'd return the stainless line, it's not worth the trouble. The nickel line is vastly easier to use.

I just replaced this line and it's actually fairly simple. The part number for my '02 996 is 996-355-175-09. The cost is around $140 USD and had to be ordered from Porsche. To access the line, just remove the driver's side headlight and bracket. Loosen the wheel well cover. Cut the old brake line by grabbing it with a wrench and bending the line. Once the line is broken, use a bolt removal socket so remove the remaining fastener. DM if you need more direction. I have photos I can share if helpful.

But how did you run the new line from that driver's side bulkhead connector, all the way over to the passenger's side? It really seems that would require removing most of the front end (diff, steering rack, fuel tank, subframe, etc..). If you can confirm that you fed the new line through, without removing anything, I would love to see pictures! On a separate note, I did receive and test my new SS line and tools.: Test DIN bubble flare on SS line. Tool seems to do a good job. Test coupler fitting.

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Ahh, the part number you provided is for the driver's side line. I can see that being more straightforward. Unfortunately, I'm having issues on the Passenger side, so I would need to rerun the line all the way over to that side. Thanks though!

Yup front and rear left (drivers) side r fairly easy. Other side not so much.

Right now I have my engine dropped to work on some cam timing issues and even with the engine down it would be a PIA to replace the factory preformed line that goes from the junction block under the car to the passenger side rear wheel. The one that goes to the drivers side rear wheel is fully accessible with the engine in even with the preformed line but used used the copper nickel line for that one and formed it myself, not perfect but pretty close. Another thing, be careful with the junction block under the care where the two front lines join the two rear lines. When I was having trouble getting good flares made I tried to use a faulty flare on this and it was leaking. I thought it might just need tightening but it continued to leak. When I took it down I saw that this aluminum junction block was damaged it one of the inlets. I went to the dealer thinking I would replace it and found out that the list price on this piece is now $335! The other side was still good so I used the one connection and bought a 3/16” 12mm union from Advanced Auto that was $9.95.

And I'm done. Still need to test the brakes, but I think I'm good. First, whichever German engineer designed the brake line path must have been paid on a per-bend basis, or he got kickbacks from the company that made the lines/tooling. The hardline inboard from the softline has a bend every 1.5 inches. Sometimes for no reason. At one point it turns 90 deg just to go through a plastic clip, and then turn 90 deg back the direction it was going. At one point it loops outboard again, down, around a coolant line, then back inboard. Where I cut, there was a 10 degree bend that really didn't need to be there. My notion that German cars are well engineered has just been shattered. This line routing is ridiculous!!! Anyway, I took some pictures. I used the straightest spot that there was, but I still had to re-bend the steel line on the car to straighten it out a bit in order to fit the coupling. But it fits very securely along/behind the frame (where it was before). I've bled the lines, and it holds the pressure from my Power Bleeder. But I'll actually use the brakes and test higher pressures tomorrow. Next to the ABS module is this bulkhead. I didn't want to drain all of system, nor have it dripping on me while working, so I removed the Front-Right here. And was able to just barely pull it out enough to plug it with a small rubber plug. Seized joint, say hello to my Dremel cut-off wheel. I had to cut through the head in order to pull the lines out of the bracket. I sprayed it with alot of water as I went. The remaining brake fluid started to smoke, and I didn't feel like dealing with fire. Perfect. This is where I chose to splice. There are NO straight sections anywhere in the first 18 inches of line. There's even a 10 degree bend right where I"m cutting. Why? No idea. Definitely glad I got the smallest line cutter I could find. Still had to bend the steel hardline a bit in order to make enough of a straight section for the splice. The bends I took out won't be missed. And I barely had enough room for the flare tool. The coolant line got pushed around a bit, but luckily it's a flexible rubber line here. Old / New line. New line spliced in place. Done!! And there was much rejoicing.

Good job! Thanks for posting how you did it.