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Thread: Double-check on my brake line placement, Mk4

  1. #1
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    Double-check on my brake line placement, Mk4

    Hi there,

    I'm woefully behind on posting my progress on my build thread. However, I'm at a step that I want to confirm I'm not painting myself in a corner that I'm going to regret later.

    I've routed my front brake lines much like EdwardB has done, though not nearly as artistically stunning as his. Sample Pics:IMG_6267.jpg

    I'm attempting to run my rear lines from the M/C, down the angled 3/4" square tubes to the inner firewall behind the foot pedals, then down thru the driver's pedalbox floor.. much like EdwardB and others have done. I'd like some help to double-check that I haven't run the lines right thru where I'll need to mount something else (e.g. fuse panel, carpeting, wiring, etc). Sample Pics: IMG_6313.jpegIMG_6314.jpegIMG_6310.jpegIMG_6311.jpg

    In the first picture, you can see where the line cuts across the front driver's panel (on the inside) before diving down to go thru the floor. I tried to leave enough room behind the line to put some form of insulation (Sound/thermal) and put carpeting on top. I've verified none of the pedals hit anywhere.

    My build is a Mk4, 302 w/ Sniper 2, painless wiring harness, using 3/16" steel lines provided by the Complete kit. Let me know if you have any guidance for me and if additional details would be helpful. As always, much appreciate your help!!

    Thanks,
    Jay
    Attached Images Attached Images
    Last edited by JsMoose; 02-24-2026 at 07:33 PM. Reason: Adding pics from phone
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  2. #2
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    Here’s a couple more of my front routing in case anyone has feedback for me .

    IMG_6149.jpgIMG_6219.jpgIMG_6220.jpg
    Attached Images Attached Images
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    Sorry, no, you should start over. First get rid of the curly pigtails, you will never get the air bubbles out of them. Second I'm sure the line running across the inside foot box could be in the way of gas, brake or clutch pedal, not ideal.
    Mrk III, 331 stroker, Borla stack injection, T5, 3:55 IRS, Power steering and brakes. Kleiner body & paint

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    Quote Originally Posted by rich grsc View Post
    Sorry, no, you should start over. First get rid of the curly pigtails, you will never get the air bubbles out of them. Second I'm sure the line running across the inside foot box could be in the way of gas, brake or clutch pedal, not ideal.
    Hi Rich,

    I'd like to hear more about your concern with the "pigtails". I've seen this on quite a few builds and the instructors at the Build School also recommended them to give us some leeway when making and installing our lines.

    Thanks!

    Rob
    289 FIA roadster (in-progress) received 11/2025
    331 SBF/Pro-Flow4 port injection/Edelbrock E-street heads/Howards hydraulic roller cam
    TKX w/.81 OD and mid-shift
    8.8" rear w/3.55 gears and three-link
    289 FIA pin drive wheels

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    Looks pretty good. You will want to use hydraulic line sealer on the brake lines so they don't leak. I know several people use Teflon tape which will degrade in the brake fluid. Good on you for using those brake lines. I couldn't get them to bend or flare for the life of me. I went with copper and made custom length lines.

    Definitely bench bleed the master cylinders and start out by gravity bleeding like the manual suggests. Good luck!
    10/29/25 MK4 Delivery Day

  7. #6
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    I can't believe anyone at the build school would recommend pigtail brake lines. A line curled up in a full loop will trap air in the top of the loop that will extremely difficult to remove. A 'J' shape line at a connection would be much better. If you absolutely want to use pigtails, have them horizontal, not vertical, and don't use anything on the flare as a sealer, they should be installed dry. NEVER put teflon tape on a car, anywhere ,,,,,,that is for plumbers and water pipes.
    Mrk III, 331 stroker, Borla stack injection, T5, 3:55 IRS, Power steering and brakes. Kleiner body & paint

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  9. #7
    Not a waxer Jeff Kleiner's Avatar
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    Quote Originally Posted by LSX View Post
    ...You will want to use hydraulic line sealer on the brake lines so they don't leak....
    No, no, no. No sealer on flared brake lines. Ever. They seal on the flare, not the threads.

    I've yet to ever put a curly Q loop in a brake line and for sure wouldn't do multiples.

    Jeff

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    I agree with Rich...no need for the pigtails, and they may cause you issues when bleeding your brakes. It'll clean up the look as well if you remove them. That top line coming out of the top inside of the footbox may get in the way of the driver's side footbox lid. The pigtails you see on some of the builds likely were employed to simply take up slack in the kit-supplied lengths of line so they didn't have to cut and reflare (kind of lazy if you ask me), or because they've seen them on mass-produced vehicles. Either way...not needed on our cars.

    I also used the kit-supplied lines. I was going to use them as templates for some NiCopp lines, but my templates looked pretty good, so I used them. I cut them to length and reflared them.

    Greg
    Last edited by gbranham; 02-25-2026 at 08:20 AM.
    Built an early MkIII years ago, sold years ago. Back after 18 years to build a MkIV
    Build Thread Here Partners: Levy Racing, Summit Racing, LMR, Breeze, Forte's Parts, Speedhut, ReplicaParts
    MkIV Complete Kit Ordered 4/18/23, Delivered 7/11/23, First start 3/15/25. Legal 6/13/25. Boss 427W, Edelbrock Pro Flo 4, TKX (.68 5th), IRS, Wilwood Brakes, 18" Halibrands, Toyo R888R Tires, Custom Speedhut Gauges

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  13. #9
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    My apologies I was referring to the my build with wilwoods and the steel brake line going into the caliper. Was recommend to use Permatex Thread Sealant.
    10/29/25 MK4 Delivery Day

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    Not a waxer Jeff Kleiner's Avatar
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    Quote Originally Posted by LSX View Post
    My apologies I was referring to the my build with wilwoods and the steel brake line going into the caliper. Was recommend to use Permatex Thread Sealant.
    And that's why I said "flared brake lines." Someone who doesn't know any better could have read your comment and mistakenly thought it applied to all.

    Jeff

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    Not a waxer Jeff Kleiner's Avatar
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    Of course, what do we know? I mean the brakes on this one worked when it came to me to finish the build:



    And what's worse is that the guy who did this put himself out there as a "Pro builder." Seriously, not joking

    Jeff

    100_3378.jpg

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  17. #12
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    I think you'll regret routing the lines inside the foot box like that. I'd find a different solution. I know redoing things isn't a great feeling, but in this case you'll be very happy you did.

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    The curly cues are used in OEM builds when the brake cylinder is attached to the body/firewall and the lines are attached to a separate frame so allow for movement between the two. They're also usually horizontal. On these cars the master cylinders are attached to the frame so there's no need to allow for any movement.

    As others said, thread sealant is for pipe threads, not flare fittings.
    My build thread https://thefactoryfiveforum.com/show...Roadster-Build

    Thread on Stainless Steel AN brake lines.
    Thread on fasteners and torque wrenches.
    Thread on Wilwood & Tilton master cylinders

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    Jeff, I hope you checked the oil level for him.
    Mrk III, 331 stroker, Borla stack injection, T5, 3:55 IRS, Power steering and brakes. Kleiner body & paint

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    When getting my car inspected by the ASE master tech, he refused to sign off on my Wilwood brakes that came from the factory with a pre-applied thread sealer on the threaded fittings. He said sealer should never be used on brake lines and that my Wilwood brakes were not approved for street use (he claimed he could not verify DOT approval for the specific Wilwood calipers and thus they were designed for off-road and race environments and he could not sign off on non-DOT approved brakes). Long story short, I found another master tech at a shop specializing in modifying Subarus for racing and he had no problems at all with the brakes.
    Mk 4 complete kit w/IRS delivered (mostly) 10-31-22. BPE 347FI w/TXK. First start July 2023. Completed build February 2024. Officially legal 05-17-2024.

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    Quote Originally Posted by JJK View Post
    When getting my car inspected by the ASE master tech, he refused to sign off on my Wilwood brakes that came from the factory with a pre-applied thread sealer on the threaded fittings. He said sealer should never be used on brake lines and that my Wilwood brakes were not approved for street use (he claimed he could not verify DOT approval for the specific Wilwood calipers and thus they were designed for off-road and race environments and he could not sign off on non-DOT approved brakes). Long story short, I found another master tech at a shop specializing in modifying Subarus for racing and he had no problems at all with the brakes.
    I remember that and I told my Master Tech about it and some of the other comments he made. He said your guy just didn't want to pass it and was making crap up.

    462295027_1077061457126227_9222020649009113592_n.jpg
    My build thread https://thefactoryfiveforum.com/show...Roadster-Build

    Thread on Stainless Steel AN brake lines.
    Thread on fasteners and torque wrenches.
    Thread on Wilwood & Tilton master cylinders

  22. #17
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    You've gotten some brutally honest feedback and I hope you take it the way it was intended. Brakes are a critical part of the build, so it is worth taking a bit of time to make the system work well and be as neat as possible. The lines that come with the kit are okay, but not a custom fit solution unless you take the extra step to make them fit better by cutting and re-flaring them to fit better. The Nickel-Copper tubing that many use is very easy to work with and not cost-prohibitive if you want to make custom lines for your car. Also, like others have stated, use sealant only on the tapered thread connections. I use Loctite 545 for these.

    If you do decide to go with Nickel-Copper, this simple tubing bender is easy to use to get bends that look great without spending a fortune on tools.

    https://www.amazon.com/dp/B0069TROZA...d_asin_title_5

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    Folks,

    Appreciate the feedback so far. Looks like I got a lot to learn here.

    1. Pigtails/Curly Q's: I was advised to do this by the build school and I've done similar before w/o issue so I didn't think badly of it. I agree if they can be avoided, it would just be one way to reduce frustration and possibility of trapping air. I'll look into minimizing these, especially the multiple loops.

    2. I verified there are no pedal interferences. I think my pics aren't quite as clear so it's hard to tell. None of my pedals get close to the firewall. However, I'll see if there are other routings that avoid this region altogether. If all else fails, I'll exit the firewall and go around the outside of the footbox. Cross my fingers on the heat.

    3. Any issues with how I went down the 3/4" tube near where the fuse panel usually is mounted? I think it's okay b/c my line is on top of the tube and the fuse panel mounts to the bottom. I could move the panel to the pass-side if needed but would prefer to place it on the driver-side.

    4. Anyone have a part number/brand/model for the thread sealer? I've never used this on threaded brake pipe fittings without any issues so I'm leery of doing it here. However, I respect your advice.

    Thanks again,
    Jay

    PS. I have no idea how the thumbnail of the sunset got in there but hope you enjoyed it. I also have no idea how to remove it.
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  25. #19
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    Quote Originally Posted by Papa View Post
    You've gotten some brutally honest feedback and I hope you take it the way it was intended. Brakes are a critical part of the build, so it is worth taking a bit of time to make the system work well and be as neat as possible. The lines that come with the kit are okay, but not a custom fit solution unless you take the extra step to make them fit better by cutting and re-flaring them to fit better. The Nickel-Copper tubing that many use is very easy to work with and not cost-prohibitive if you want to make custom lines for your car. Also, like others have stated, use sealant only on the tapered thread connections. I use Loctite 545 for these.

    If you do decide to go with Nickel-Copper, this simple tubing bender is easy to use to get bends that look great without spending a fortune on tools.

    https://www.amazon.com/dp/B0069TROZA...d_asin_title_5
    Thank you. I've got a similar tool that I've been using. As well as a 15/16" socket to do the pigtails that have raised some eyebrows on this thread!
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  26. #20
    Not a waxer Jeff Kleiner's Avatar
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    Quote Originally Posted by JsMoose View Post
    4. Anyone have a part number/brand/model for the thread sealer? I've never used this on threaded brake pipe fittings without any issues so I'm leery of doing it here. However, I respect your advice.

    Thanks again,
    Jay
    You don't have Wilwood brakes therefore you do not have NPT adapters which would require sealer. As has been stated...you DO NOT use sealer on flared fittings.

    Jeff

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    Quote Originally Posted by Jeff Kleiner View Post
    You don't have Wilwood brakes therefore you do not have NPT adapters which would require sealer. As has been stated...you DO NOT use sealer on flared fittings.

    Jeff
    Oh, ok. Now I understand. Thanks for the double-clarification!

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    Quote Originally Posted by Jeff Kleiner View Post
    You don't have Wilwood brakes therefore you do not have NPT adapters which would require sealer. As has been stated...you DO NOT use sealer on flared fittings.

    Jeff
    Is that an NPT fitting in the end of the Wilwood master cylinders? I don't remember since I threw mine in the trash
    My build thread https://thefactoryfiveforum.com/show...Roadster-Build

    Thread on Stainless Steel AN brake lines.
    Thread on fasteners and torque wrenches.
    Thread on Wilwood & Tilton master cylinders

  29. #23
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    Quote Originally Posted by Jeff Kleiner View Post
    Of course, what do we know? I mean the brakes on this one worked when it came to me to finish the build:



    And what's worse is that the guy who did this put himself out there as a "Pro builder." Seriously, not joking

    Jeff

    100_3378.jpg
    Thanks Jeff, you made me use up my self limited one “Whiskey Tango Foxtrot” for the day. Now I have to be careful.

    Norm
    Mk4 base kit 7721, 331 Stroker, Holley Sniper EFI, Wipers, Heater, Whitby Soft Top, Drop trunk mod and more

  30. #24
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    Quote Originally Posted by gbranham View Post
    I agree with Rich...no need for the pigtails, and they may cause you issues when bleeding your brakes. It'll clean up the look as well if you remove them. That top line coming out of the top inside of the footbox may get in the way of the driver's side footbox lid. The pigtails you see on some of the builds likely were employed to simply take up slack in the kit-supplied lengths of line so they didn't have to cut and reflare (kind of lazy if you ask me), or because they've seen them on mass-produced vehicles. Either way...not needed on our cars.

    I also used the kit-supplied lines. I was going to use them as templates for some NiCopp lines, but my templates looked pretty good, so I used them. I cut them to length and reflared them.

    Greg
    Greg,

    Thanks for the tip on the footbox lid, I'll check that before buttoning up. Did you see any other concerns with fitment such as fuse panels, etc? I think I'm good based on pics from other people's builds, but if needed I'll get the parts out and dry fit to make sure. This is hard for me b/c I have parts stored in different locations due to space constraints.

    Glad to hear you were able to utilize the kit-supplied lines with success. I'm going to stick with them if I can. Going to try to get rid of as much of the pig tails as possible first.

    regards,
    Jay
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    No other concerns from my perspective; I think the group covered it all.

    Greg
    Built an early MkIII years ago, sold years ago. Back after 18 years to build a MkIV
    Build Thread Here Partners: Levy Racing, Summit Racing, LMR, Breeze, Forte's Parts, Speedhut, ReplicaParts
    MkIV Complete Kit Ordered 4/18/23, Delivered 7/11/23, First start 3/15/25. Legal 6/13/25. Boss 427W, Edelbrock Pro Flo 4, TKX (.68 5th), IRS, Wilwood Brakes, 18" Halibrands, Toyo R888R Tires, Custom Speedhut Gauges

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    I routed the rear line through the footbox, but brought it out to the outboard side and down the 2" round tube. I did not want the brake line running very close to the exhaust or be exposed to road rash from the left front tire. It clears the clutch cable bellcrank just fine and is away from the the pedals. The front line follows the rear down to the upper left 3/4 square tube and on to the X frame.

    DSC02992.JPGDSC02990.JPGDSC02991.JPG
    Last edited by Rebostar; 02-26-2026 at 06:18 PM.

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    Two thoughts. I encourage you to buy some Nicopp (it's inexpensive) and try it. I listened to the experts here and once I tried it, I switched and redid my lines. Glad I did. In case you're interested, posts 99, 111, and 131 in my thread detail my brake line "journey".

    Also, I'd redo the line with the pigtail above the pedal box. If still using pre-flared lines, put the pigtail on the other end. Once you get the sheet metal in place and all of the wiring in there, you'll wish that pigtail wasn't there taking up valuable real estate.

    Either way, keep posting here and soak up everything you can. Lots of skilled builders who enjoy helping and sharing. It has been invaluable to me.

    Pat
    MK4 complete kit Nov 2024, Blueprint 347, TKX, Hyd clutch, IRS, 3.55, touring shocks, 17" wheels, 11.65 brakes, Build Thread

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