2004 Sierra Denali Brake Line Replacement

green55 · March 10

Planning to replace all of my brake lines. One thing led to another with a different project and I noticed how crusty they look. I know its a common problem and I don't want to wait for them to start leaking before fixing.

I noticed that I have short stretches of braided, flexible lines between my master cylinder and the proportioning valve, then again between the proportioning valve and the ABS module. I'm not sure if "braided line" is the right term, but hopefully y'all know what I mean. Attached a pic -- not super clear because I took it at night.

All of the kits that I have seen, or if I were to bend myself, only have hard lines. I have only seen hard lines in the youtube tutorials I have watched. Is it okay and expected to replace the flexible lines with hard lines?

PS: I do have a quadrasteer truck. I don't think it is relevant for the front portion, but do know that the rear brake line configuration is slightly different.

CamGTP · March 10

I live in the rust belt and more often that not those braided brake line sections are in really good condition still with no damage or corrosion to the fittings. It's the lines under the truck and really close the frame that rust away from the salt.

If your braided lines aren't in bad condition at the fitting ends, just leave them and replace only the hard line sections with a kit that fits your truck.

green55 · March 10

Thanks - they're not bad compared to under the truck, but one in particular is showing some rust. Do y'all just replace with solid lines if you need to?

green55 · March 10

To be more clear -- the ones from the master cylinder to proportioning valve look fine. It is the ones off of the proportioning valve headed to the abs module that give me concern. Those are partially braided

CamGTP · March 10

I guess it depends on how bad they are. Guys from the south think a little rust is the end of the world and up here they can look like hell and still be completely fine lol.

Rock Auto does sell one of those braided lines but I don't think they have all of them. Aftermarket braided lines can work too, just the fittings need to match up.