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#1
Replacing Brake Lines - 2003 GTP
SE Level Member
09-23-2018
One of the rear lines popped on our 2003 GTP. It looks like right at the bracket that attaches it to the lower firewall. Got looking at it and none of the lines look good. I'm going to replace them all. It does not look like any fun. Anyone done it? Tips or tricks?
As an aside, we still had some back braking action. I drove it 9 miles home. I jacked it up and freed the lines up from one of the clamps to try to identify the source of the leak. Once I realized the severity of the situation, I put it back on the ground. When I went to move it I had NOTHING at all brake-wise, which is scary because I live on a really steep hill. My driveway is 500 feet long down to the street. But, the parking brake works so I was able to move it off to the side using that until I can figure next steps.
It looks like SS Tube makes a stainless kit. The issue might be, however, getting the old lines out and new ones in. It's tight in there.
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#2
Re: Replacing Brake Lines - 2003 GTP
GTX Level Member
09-23-2018
I had this problem too, only it was the rear brake lines at the fuel filter. Getting the old line out is not that hard, just cut them to small manageable sections to remove. Getting the new ones installed in one piece can be challenging, I have not installed lines at the front of a Grand Prix, but I am sure others have and can give advice on getting the line past obstacles. On the very long lines, or ones that go in tight spots, you could if needed would be to cut the line in an accessible spot and add a double flare union to reconnect.
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#3
Re: Replacing Brake Lines - 2003 GTP
09-23-2018
i bought one of them kits, and a fuel line kit , cause i figured if i went taking them brackets off under the car the fuel lines would start to fail. they looked as bad as the brake lines.
i ran out or "will" to do them lol had the shop across the street install em for me. the fuel line kit failed to reach the fuel rail, so they cut the lines and mated them up to the good line still.
same for the brake lines, they ended up cutting out all the bad lines and re connecting the new to good old.

98 Buick Regal GS, F body brakes, Caddy STS wheels, tinted tails
L36 bottom end, lightly ported heads, 1.95 roller rockers, headers, gen 5 N* 3.0 pulley, FSIC, 42 lb injectors, a BrandonHall rebuilt trans, DHP tuned and AEM water/Meth injection https://goo.gl/gpV5kW
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#4
Re: Replacing Brake Lines - 2003 GTP
SE Level Member
09-23-2018
Yeah the fuel lines don't look much better, but operate under much lower pressure. Going to keep my fingers crossed on those.
I may just splice in the new brake lines in convenient spots. The rear ones will be tough to get up in there in one piece because they're so long. Front right definitely needs replaced (though it's not leaking yet) so I'm going to do my best to get that one in there all in one piece. Plus there's no good place to splice into that one anyway. But, again, my current issue is with the rears. I think the other one popped open while I was messing with it, hence the total loss in brakes now. The rear linestake so many wacky bends I'm a little worried about what I'm going to need to do to replace them.
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#5
Re: Replacing Brake Lines - 2003 GTP
09-23-2018
the line that goes across the rear sub frame, that one blew out long ago on me. i cut the line a few inches past the line block on the pass side rear, then used nicop line from that point, across the back of the gas tank and spliced it in to the good line in the d/s back tire area. that one took all of 15 minutes to fix.

98 Buick Regal GS, F body brakes, Caddy STS wheels, tinted tails
L36 bottom end, lightly ported heads, 1.95 roller rockers, headers, gen 5 N* 3.0 pulley, FSIC, 42 lb injectors, a BrandonHall rebuilt trans, DHP tuned and AEM water/Meth injection https://goo.gl/gpV5kW
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#6
Re: Replacing Brake Lines - 2003 GTP
SE Level Member
09-23-2018

Originally Posted by
Scottydoggs
the line that goes across the rear sub frame, that one blew out long ago on me. i cut the line a few inches past the line block on the pass side rear, then used nicop line from that point, across the back of the gas tank and spliced it in to the good line in the d/s back tire area. that one took all of 15 minutes to fix.
Mine look okay back there. The lines coming from each rear wheel join the lines with a union near the left rear tire. Not sure if that's factory or a repair.
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#7
Re: Replacing Brake Lines - 2003 GTP
09-23-2018
your gonna find a few factory unions through out the system.

98 Buick Regal GS, F body brakes, Caddy STS wheels, tinted tails
L36 bottom end, lightly ported heads, 1.95 roller rockers, headers, gen 5 N* 3.0 pulley, FSIC, 42 lb injectors, a BrandonHall rebuilt trans, DHP tuned and AEM water/Meth injection https://goo.gl/gpV5kW
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#8
Re: Replacing Brake Lines - 2003 GTP
09-23-2018
I just replaced the passenger side front brake line with a new OEM steel line since it rusted out where it touches the insulation on the firewall (note- do not put them back there or they will rust out again). I just cut the old one out and slowly worked the new one into place. Yes, I did have to slightly bend it to get it into position but it didn't kink so I'm good. My rear has new ni-cop line for both sides. That stuff bends easy and I was able to reuse my factory fittings so no unions in there. Had that one blow out on a panic stop a few years back. Talk about fun.
Or just get a big roll of ni-cop line, a double flare kit and make your own lines up then you can run them where/how you want instead of getting prebent ones. Up to you.
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#9
Re: Replacing Brake Lines - 2003 GTP
SE Level Member
09-24-2018

Originally Posted by
FordMan77
I just replaced the passenger side front brake line with a new OEM steel line since it rusted out where it touches the insulation on the firewall (note- do not put them back there or they will rust out again). I just cut the old one out and slowly worked the new one into place. Yes, I did have to slightly bend it to get it into position but it didn't kink so I'm good. My rear has new ni-cop line for both sides. That stuff bends easy and I was able to reuse my factory fittings so no unions in there. Had that one blow out on a panic stop a few years back. Talk about fun.
Or just get a big roll of ni-cop line, a double flare kit and make your own lines up then you can run them where/how you want instead of getting prebent ones. Up to you.
That's where my front right is going bad - where it's touching the insulation. It hasn't popped yet but I can't leave it like that.
I hadn't heard of nicopp until I started doing this research. The stock lines take more than a couple of 90-degree bends before they run to the back. Is the nicopp flexible enough to duplicate that path? What size is it? I see 3/16" coming up in most of my searches.
Thanks!
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#10
Re: Replacing Brake Lines - 2003 GTP
GTP Level Member
09-24-2018
I got my brake lines from Classic Tube. Fitment was great. The kit came with everything I needed. Except for the hoses leading up to the actual calipers. Those you need to get on your own if you are replacing them. You also need to buy Proportioning Valves for the rears. You can re-use the old ones if you want. I bought new Dorman ones. I recommend doing the fuel lines as well. Order them from Lines-To-Go. They also sell the fuel line disconnect tool pretty cheap and other hoses and hose fittings you might need.
To make the job easier, you will need to take off the cruise control module, take out the master cylinder, and take out the brake module. This clears up that corner by the strut tower. I didn't take out the modules that and mann was it a pain in the ass to squeeze those lines through that armpit. You're gonna need to drop the front sub-frame, and probably the rear subframe. The brake line for the rear passenger side snakes up along the edge of the rear sub-frame, but it could maybe be finagled in there without being dropped. Also be prepared for cutting/sawing off the old brake lines because the unions are likely frozen at the brackets in the wheel wells. I took those brackets off and painted them.
Here are few links to my replacement:
Fuel Lines
Luke's GTP
Brake Lines:
Luke's GTP
Some Install Pics
01. Luke's GTP
02. Luke's GTP
03. Luke's GTP
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#11
Re: Replacing Brake Lines - 2003 GTP
GTP Level Member
09-24-2018
Ooops. The link for Brake Lines is wrong. Below is the correct link.
Brake Lines:
Luke's GTP
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#12
Re: Replacing Brake Lines - 2003 GTP
SE Level Member
09-24-2018

Originally Posted by
CHI2000GTP
Ooops. The link for Brake Lines is wrong. Below is the correct link.
Brake Lines:
Luke's GTP
Do you have a part number for the brake line kit? They don't show it on their site or in their catalog.
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#13
Re: Replacing Brake Lines - 2003 GTP
GTP Level Member
09-24-2018
I ordered for a year 2000, but it's all the same. You want Part# BU1069-OE (OE is for Original Equip., if you want stainless, its SS)
Call them to place the order. Doesn't show on there catalog for some reason, you're right. Weird....
It's a 10 piece kit. About $250 if I remember correctly.
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Post Thanks / Like - 1 Thanks, 0 Likes, 0 Dislikes
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#14
Re: Replacing Brake Lines - 2003 GTP
SE Level Member
09-24-2018
You have 4-wheel ABS, right?
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#15
Re: Replacing Brake Lines - 2003 GTP
GTP Level Member
09-24-2018
Yes.
4 wheel ABS. Traction Control. Supercharged.
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#16
Re: Replacing Brake Lines - 2003 GTP
SE Level Member
09-24-2018
It would seem to be identical. I asked Classic Tube to verify though.
My hesitation with the nicopp now is that the factory lines have braided steel for flexing where it meets the ABS module. Looks like Classic Tube does something similar but with rubber.
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#17
Re: Replacing Brake Lines - 2003 GTP
GTP Level Member
09-24-2018
Yeah. They got a pretty thick rubber hose at those ends. If you're replacing the hoses at the calipers with braided hoses like the ones ZZP sells from Goodridge,..... know that the rear stainless hoses will be too short. I had to end up buying the regular ol' rubber hoses from Dorman for the rears after dealing with leak after leak. Sucks spending 100+ on that braided steel kit and only being able to use the front hoses.
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#18
Re: Replacing Brake Lines - 2003 GTP
SE Level Member
09-24-2018
Okay so they had 3 nild steel kits with the same P/N of P01029 for the 1997-2001 GP. One was $156, one was $176 and one was $220. I opted for the $156 one since there was literally no difference between them. I didn't want to spring for stainless. The mild steel lasted 15 years. The pain of this installation will be behind me in 15 years when I have to do it again. Or I may be dead by then - who knows?
Thanks for the advice and tips. The nicopp route was tempting but I don't want to wind up with a bunch of unions.
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#19
Re: Replacing Brake Lines - 2003 GTP
SE Level Member
09-24-2018

Originally Posted by
turbojimmy
Okay so they had 3 nild steel
That's 'mild' steel.
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#20
Re: Replacing Brake Lines - 2003 GTP
SE Level Member
09-29-2018
Well I dug into this project today. The car "only" has 75k on it so it's not really very rusty under there. The lines popped in the bracket behind the engine. They look fine the whole way underneath the car. Even so, I disconnected the rears at the union back by the right rear tire and intend to run the new Classic Tube lines back there. It's a nice kit, I'm just not sure how I'm going to fish those rear ones where they need to go. The old ones came out easy because I cut them. I haven't cut the right front one out yet, but it too needs to be replaced.
I'm going to study CHI2000GTP's pics some more before I start putting it back together.
Are there any special bleeding procedures with the ABS? My plan was to gravity bleed each corner until I got fluid out and then bleed it the old fashioned way (pump the pedal, open the bleeder, close the bleeder, lather, rinse, repeat).