Anyone replaced all the brake lines?

rybo · Nov 14, 2024

I have a 73 Mach 1 that was sitting for 30-40 years, and the brakes didn't work at all which makes sense. I replaced the master cylinder, and went through the bleeding process. The front discs were normal, easy to bleed and work fine now.

The rears I can't get to bleed, no fluid flowing and with the master cylinder cap off the fluid shoots back up through the MC. I think the proportioning valve is either stuck or rusted up. So I figured I would just replace it, but in doing so all the line connectors are rusted and I won't be able to back them off without completely stripping it off.

So then I figured maybe just cut it all out and replace the lines and PV, something I would end up doing eventually anyway, just wasn't looking to do it now. But looks like I don't have much of a choice, so my question is how much of a job is it? I've never replaced brake lines before. Are the lines just simply bolted up to the frame and relatively easy to swap out, or is there more to it that I'm missing? Just curious on any advice you have before I start ripping lines out.

I have front disc, rear drum. Thanks!

MikeGriese · Nov 14, 2024

There are a number of kits out there in stainless or mild steel - pick your poison. Note that the lines will come folded, so you will need to straighten them when you install them. The line to the rear runs in the torque tube tunnel and up to and across the drivers side firewall. The right front brake line runs across the firewall above the engine, so that is a bit easier to access. I installed mine when the drive train was removed, I can see where it might get tricky working around the engine, transmission and firewall accessories.

rybo · Nov 14, 2024

MikeGriese said:
There are a number of kits out there in stainless or mild steel - pick your poison. Note that the lines will come folded, so you will need to straighten them when you install them. The line to the rear runs in the torque tube tunnel and up to the firewall. I installed mine when the drive train was removed, I can see where it might get tricky working around the engine, transmission and firewall accessories.

Ok thanks thats what I was afraid of. I was thinking of just getting straight line and making my own lines, rather than the pre-fitted, that might help me avoid the areas I can't get to. Or I just hold off on that line till I pull the engine and tranny down the road.

Bentworker · Nov 14, 2024

Stick with steel or NiCop The pre-bent kits are okay, but you can do a lot with a 25’ coil, some skill, a bender and a double flaring tool. The “slot machine” type flaring tools are superior to the old type.

Stainless is a pain to work with, so much so that I believe it should be avoided.

25’ roll of brake line is less than $8 from Rock Auto

rybo · Nov 14, 2024

Bentworker said:
Stick with steel or NiCop The pre-bent kits are okay, but you can do a lot with a 25’ coil, some skill, a bender and a double flaring tool. The “slot machine” type flaring tools are superior to the old type.

Stainless is a pain to work with, so much so that I believe it should be avoided.

View attachment 95161

Thanks, yeah I was just looking into that option, I think I'd prefer just making my own steel lines from the 25' roll and going that route.

fd7 · Nov 15, 2024

I replaced all mine using pre-bent from InlineTube. They fit perfectly. I cant imagine bending myself and getting them to fit correctly. There's LOTS of bends, lots of 90's. They came with a nice gentle loop bend in a huge box. Were easy to straighten up for install. Just my 2 cents.

dawson357 · Nov 15, 2024

Just did that to my 73 Grande. Got the premade SS ones from Classic Tube. The short lines were OK except the left rear was way too short. The long line from front to back was not bent correctly at all at the rear, not even close and had to clean and reuse my old one. I too had a couple of the fittings that were stuck in the PV and could only get them out when I pulled the PV and could get some torque on the fitting in a vise. Major pain getting the front to back line in with the transmission installed. Fortunately, I was swapping transmissions and did it then. The SS lines are much stiffer than the standard steel and a little harder to tweak to get them to line up. If you can rebuild your PV, would be good to keep the original. The Chinese ones are iffy and the mounting bracket is either on the wrong side or you have to attach it yourself (good luck with that). The brakes have been the bane of my journey with this car. Hopefully will drive it around the block this weekend and pray it'll stop.

rcadd1ct · Nov 15, 2024

I used classic tube. I went stainless.

Unsure if I would do that again as I had trouble getting them to seal at first.

They were an exact fit, though.

giantpune · Nov 15, 2024

I had the same issue as OP on one of my 73 mustangs. The issue turned out to be the rear rubber hose. It connects the steel line in the transmission tunnel with the steel lines on the rear axle. Mine was caked with crud. I replaced that rubber hose and the brakes worked again. I still have the long line I was going to install but didn't end up needing.

I have replaced all the lines before. If you can get the front of the car high enough off the ground, you can snake the long front-to-back line in with the drivetrain still in place. You may have to remove some small components like shock tower brace and disconnect transmission linkage.

Hemikiller · Nov 15, 2024

giantpune said:
I had the same issue as OP on one of my 73 mustangs. The issue turned out to be the rear rubber hose. It connects the steel line in the transmission tunnel with the steel lines on the rear axle. Mine was caked with crud. I replaced that rubber hose and the brakes worked again.

Like GP noted, start with the body to rear axle hose before committing to a full line replacement. It's very common for the interior of the line to be blocked due to swelling of the hose.

I'd much rather use a prebent kit than making my own. Did plenty of that in my early days, the made to fit stuff is so much easier, even with the tactical planning of how to get it in the car with things in the way. I used Classic Tube for all my cars.

MikeGriese · Nov 15, 2024

If you think snaking prebent lines around the drive train is tricky - just wait until you try bending your own. You'll be going in and out over and over.

Buy yeah - unless you have an obvious crush in the hard lines, start looking for the blockage. Soft lines do eventually fail.

Stanglover · Nov 15, 2024

My thoughts;
I replaced all the lines with SS. The kits were from NPD, so no idea who made them. I had no real problem with the front system. I was replacing the old drums with discs, so it was a no brainer to do all the lines. The rear was a bit more challenging but doable. In my rear install, I split the system to incorporate an adjustable bias valve, so needed to do some creative bending for it to work. For sure SS tube is difficult to work with especially if you need to reshape some of the pre-bent sections. It's like everything else, take your time and think it through before hand.
Doing it again, I'd use steel tubing for some of it and pre-bent for the front section. Ordinary steel brake line will out last the car, or you, anyway.
This pic is from 2012 with motor out. It shows the rear bias valve separated from the distribution block that now is just a junction for the front brakes and I have no brake failure light now. I later added a power booster and redid the plumbing at a much later date. It looks a lot neater now!!

roboconklin · Nov 15, 2024

rybo said:
Thanks, yeah I was just looking into that option, I think I'd prefer just making my own steel lines from the 25' roll and going that route.

I used the nickel/copper to make mine. It’s easier to bend and flare.

351c1971 · Nov 15, 2024

rybo said:
I have a 73 Mach 1 that was sitting for 30-40 years, and the brakes didn't work at all which makes sense. I replaced the master cylinder, and went through the bleeding process. The front discs were normal, easy to bleed and work fine now.

The rears I can't get to bleed, no fluid flowing and with the master cylinder cap off the fluid shoots back up through the MC. I think the proportioning valve is either stuck or rusted up. So I figured I would just replace it, but in doing so all the line connectors are rusted and I won't be able to back them off without completely stripping it off.

So then I figured maybe just cut it all out and replace the lines and PV, something I would end up doing eventually anyway, just wasn't looking to do it now. But looks like I don't have much of a choice, so my question is how much of a job is it? I've never replaced brake lines before. Are the lines just simply bolted up to the frame and relatively easy to swap out, or is there more to it that I'm missing? Just curious on any advice you have before I start ripping lines out.

I have front disc, rear drum. Thanks!

R&R is pretty straight forward with Classic Tube pre bent lines. Worse case you will have to cut the old lines at the fitting and use a stripped bolt head remover to remove any stuck fittings. You might also consider rebuilding the distribution block/proportioning valve as well.

The Heff · Nov 15, 2024

I replaced all of mine with the nickel/copper and used the Hand held brake flaring tool ( Ebay £19.00 ) and a hand held bending tool to create smooth curves.
Can someone advise me, What size is the brake pipe, are there two sizes, because I'm sure my PV has two different size threads, or has this been done deliberately by the manufacturers so that you do not put the wrong pipe in the wrong PV port?

tony-muscle · Nov 15, 2024

I replaced all of mine with steel, not SS. I bleed my brakes often as to reduce the amount of moisture build up. Not necessarily due to rust issue but due to the lower boiling point with wet brake fluid.

rybo · Nov 15, 2024

tony-muscle said:
I replaced all of mine with steel, not SS. I bleed my brakes often as to reduce the amount of moisture build up. Not necessarily due to rust issue but due to the lower boiling point with wet brake fluid.

Yeah I'm with you there, brake fluid is cheap and easy enough to bleed em.

ROCKET70 · Nov 15, 2024

I replaced my brake lines in 2021 could not find pre made because of Covid. I tried my best and got them close but not perfect.
I have done lots of brake lines in my life time, it wasn't hard except the tunnel mainly because I can't bend my neck.
I would suggest to buy the pre made ones it will look like factory and a lot easier.

giantpune · Nov 15, 2024

rybo said:
Yeah I'm with you there, brake fluid is cheap and easy enough to bleed em.

IDK, I've got cars with 25yr old brake fluid in them still working fine. Its a sealed system. Where's all the water coming from?

rybo · Nov 15, 2024

giantpune said:
IDK, I've got cars with 25yr old brake fluid in them still working fine. Its a sealed system. Where's all the water coming from?

That's fair, I come from the racing world where we would constantly be swapping out / bleeding the brakes so it's just become habit I guess. When you have a fast car the brakes become a big focus for us. Plus gives me a reason to drink beers in the shop

Anyone replaced all the brake lines?

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