Thread: Replacing rear hard lines

my line that coiled up in the rear sub frame rotted out. so i cut the line in the d/s rear wheel well in a open area. then cut the line on the pass side 6 inches from the union where it turns into a rubber hose to caliper.

get nicopp brake line, it bends like butter, i got a 5 foot long line fished it behind the gas tank and bent it round the corner to the cut lines, you can buy/rent a flair tool, buy unions and line nuts, or like i did, just used compression fittings.

NiCopp is the way to go...

I went stainless, and it can't be flared without special tools. NiCopp is easy peasy...

search one man brake bleeder on youtube, and never need help bleeding your brakes again. some clear tubing and used a water bottle or the likes is all you need. does a real good job too. maybe better then the pump the pedal bleed em out old school deal with two people.

if your master cylinder res is dry you will need to bleed it first, then bleed the brake calipers. blown lines sitting tend to gravity drain the res on ya.

i take a wrench, then wrap a rag around the line nut and wrench, lay one underneath the lines too, ( this can be messy) now this time you need help. fill the res, get a helper pump the brakes and then hold them, you crack the line nut using the nut as the bleeder valve, shut the nut before the helper lets the pedal back up. do this to both lines till you hear no more air coming and just fluid is coming out. then head off to the brake calipers.

found my pics.

driver side where i cut the line



pass side at the union


and the bend around the back of the gas tank. nothing holds it in place, its been there maybe 4 years now, no issues at all.

and another quick tip, sand the lines before you cut them, this way your working with clean metal when you flair or use compression fitting, you need the line clean of rust or the furler or line nuts for the unions will have a hard time going on over rusted line.

Good points here. The only place that I could find that makes a pre-bent set for the Grand Prix was SS Tubes. I got THIS KIT and it fit OK, except that they didn't make any allowances for the proportioning valves for the rear brakes. I wound up having to cut and flare the stainless lines and that was no fun at all. If I had to do it again it would be NiCopp all the way.

Some additional points, it's worth it to just replace the rear proportioning valves, they are only $15 each Dorman 905952. Much easier than trying to get the lines off of them. note that the fitting sizes are different on the intake and outflow side of these valves, be sure to install facing the right way.

The other surprise is that these lines are not a typical double flare, they are what's called an ISO bubble flare. The flare is made with a different flaring tool and the fittings are different too. Also line is 3/16" size.

Not sure if you are replacing the line all the way back from the ABS unit or just the part that passes across the back to the RR. If just doing the back piece, note that there is a flare coupler just ahead of the LR wheel. The male ISO bubble fitting is relatively easy to find at the local parts store, but that female side can;t be found anywhere it seems. With a little PB blaster you can save those fittings and re-use on the new lines. When you get the loaner flare kit be sure to ask for the ISO bubble flare kit, not the 45* double flare kit.

As far as bleeders, I have the https://www.summitracing.com/parts/m...AvD_BwE]Motive Power Bleeder[/url] with the GM cap. I originally bought it when I changed the brake lines in my Suburban and it also fit the GP reservoir cap.

Also helps to have a good set of flare wrenches if you don't already. I snapped my HF 12mm in half (the head not the handle) doing this job....

Did you paint or coat them with something? The reason they rust out is because GM used plain, uncoated steel instead of dipped or galvanized. Your pick and pull lines will rust too if you just installed them as is. One reason to use NiCopp, it won;t rust.