Need advice regarding corroded rear brake hard line fitting

[eljay]

So, my B6 has typical North East problems: rusted bolts and nuts at the rear! It sucks since underneath the car looks quite decent actually. But I may just look around for a rear subframe in good shape and rebuild it with all new bushings and control arms and then swap the subframes. Anyways, that's another chapter for the future.
The problem of the day is rear brake line fittings.
I am putting rebuilt B7 rear calipers onto the car and was going to install new StopTech SS flex lines, but that's just not gonna happen. My fittings are completely corroded similar to this thread. On the passenger side, there's no nut left to turn and the spring clip is crumbled and gone. On the driver's side, the nut is still there, but I won't even try to turn it.
My passenger side caliper was/is leaking and it looks like it's leaking from the banjo bolt connection - likely the crush washers are gone and letting some fluid out.

So, at this point, I'm thinking about these two options:
Option 1.
Install the B7 calipers onto the existing flex lines and install my new B7 pads and rotors etc. (the carriers and shields are fitted already). When installing the banjo bolt, fit another copper crush washer (anyone know the size?) between the banjo bolt and caliper. This is because I believe that the OEM flex hose has the banjo bolt fitted in the line and the crush washers are integrated with it unlike aftermarket lines, which have the washers available separately. See here for OEM and here for aftermarket to see what I mean. Then I would just take the car to a local shop to have the lines replaced and get them to cut off the old fitting and flare the line and install a new flare nut and the new SS lines in the rear. My worry is that putting on new B7 brakes and flushing the system, I will need to go bed everything in and that crush washer leak may be on the other side of the banjo fitting and it will leak and the whole bed-in drive may not go as planned!

Option 2.
I don't even know whether this is possible, but can I cut the rear hard line just above the flare nut and then use one of those brake line flare tools (like this one?) to flare the line and fit a new flare nut onto it? I've never done this and every DIY on this shows it being done with brake lines off the car, which I won't be able to do. Is it possible to it with the line still on the car? Besides the space being incredibly tight and dirty I think I would loose all brake fluid and run the master dry, correct?

If I go down the #2 path, it's a path with no return as once I cut that line, the car is going nowhere and I have to finish it in my garage. Or perhaps I'll go with Option 1 and instead of proper bedding in, I just limp slowly to the nearest garage and get them to flare the line and install the new SS lines and I'll bed everything in afterwards. Sure, I may have some glazing from slow braking, but I should be able to get rid of it through a few proper bedding cycles, right?

This near the end of my B7 brake upgrade saga, which was supposed to be a weekend affair, but it's now dragging on week 4 as after every completed step I discover a problem before I can continue.
But I'm so close now, I can smell the brake pads burning during the break-in! So, please help.

Thanks guys!

[seanf86]

look farther down the car and look for a factory union that you can hopefully undo and replace the whole section of line, they are usually cheap, I had the same thing happen on the front of an old B5 and the line from the abs pump to pass front wheel was $32 at the dealer.

[eljay]

Thanks, but these are the rear lines and they run from the rear to the ABS pump and each would cost me around $100, so I'm looking for repair alternatives.
At the same time, I just want to drive the damn car again, so I may just do Option 1 and take it to a shop to repair the fittings and install the SS lines.

[diagnosticator]

The banjo bolt fitting uses two copper seal rings, one on each side of the banjo fitting.

The corroded line coupling fitting can be cut out and the line reflared with a new line fitting nut. Remember, the fittings are metric threads. Brake lines must be double flared, a single flare is unsafe. A double flare is created by flaring the tube, then folding the tube flare back on itself matching the angle of the tube fitting. BTW, braided stainless brake hoses are not reliable with limited life span on the street.

[evo_ski]

You are doing literally the exact swap I am trying now. My rear connections are rusted and will likely not be able to be removed. I am thinking about trying to find a partout and see if I can take a full set of rear lines from the part out and swap them, or try to attempt flaring a new connection on with the line on the car already.

Very interested to see how this goes. Please update once you are done to let me know how this ended up for you. Good luck!

[MoparFreak69]

The banjo bolt fitting uses two copper seal rings, one on each side of the banjo fitting.

The corroded line coupling fitting can be cut out and the line reflared with a new line fitting nut. Remember, the fittings are metric threads. Brake lines must be double flared, a single flare is unsafe. A double flare is created by flaring the tube, then folding the tube flare back on itself matching the angle of the tube fitting. BTW, braided stainless brake hoses are not reliable with limited life span on the street.

Typically our cars utilize aluminum crush washers instead of copper. Cheaper to produce yet more prone to corrosion.

Unfortunately these cars use a bubble flare that requires the correct flare tool to make. A standard flare will not seal to the factory connection no matter how hard you torque it down. A lot of shops around here won't even touch one because of how difficult they are to make perfect. If they aren't pretty much perfect they leak.

[eljay]

The banjo bolt fitting uses two copper seal rings, one on each side of the banjo fitting.

The corroded line coupling fitting can be cut out and the line reflared with a new line fitting nut. Remember, the fittings are metric threads. Brake lines must be double flared, a single flare is unsafe. A double flare is created by flaring the tube, then folding the tube flare back on itself matching the angle of the tube fitting. BTW, braided stainless brake hoses are not reliable with limited life span on the street.

Thank you.
I can see those copper seals on the Stoptech kit I have, but from my reading and the links I posted above it seems that the factory rubber flex line has the bolt and the seals already on and they don't come apart like aftermarket hoses.

I keep looking at the rear caliper after I cleaned around the banjo bolt and now it looks pretty dry, so perhaps it was the caliper seals that were leaking rather than the bolt. It would be more likely given that the other side caliper was replaced just last Fall because it leaked.

I think I will just leave the lines for now and install my B7 calipers.

[eljay]

You are doing literally the exact swap I am trying now. My rear connections are rusted and will likely not be able to be removed. I am thinking about trying to find a partout and see if I can take a full set of rear lines from the part out and swap them, or try to attempt flaring a new connection on with the line on the car already.

Very interested to see how this goes. Please update once you are done to let me know how this ended up for you. Good luck!

I am at a point where the car has been on the jackstands for far too long and since this ain't broke (yet!!), I may just leave it and get a shop I teust deal with the lines. I will get them done before winter though.

I hope you are looking at southern junkyarda for a line that's not corroded! :)

[eljay]

Typically our cars utilize aluminum crush washers instead of copper. Cheaper to produce yet more prone to corrosion.

Unfortunately these cars use a bubble flare that requires the correct flare tool to make. A standard flare will not seal to the factory connection no matter how hard you torque it down. A lot of shops around here won't even touch one because of how difficult they are to make perfect. If they aren't pretty much perfect they leak.

Yes, from what I've read, the factory washers are aluminum.
There's an OTC ISO bubble flaring tool on Amazon that's even reasonably priced, but as I mentioned above, I think I may just leave it for now and get a competent shop to do it.

[Let it snow]

On an old VW of mine i went to the auto parts store and grabbed a pre made 4 foot made bubble flared line. Then somewhere towards the front of the car with easy access to the brake line i cut the line and did a standard flare. Then install the bubble flair at your new brake ends and run the line to the front. Connect with a standard flair connector. Ideally you should replace lines to the factory connections but this got me out of a bind.

[Let it snow]

Never mind my above comment. I did not do a standard flair conector. I used bubble. DERP..DERP...

[diagnosticator]

Yes, from what I've read, the factory washers are aluminum.
There's an OTC ISO bubble flaring tool on Amazon that's even reasonably priced, but as I mentioned above, I think I may just leave it for now and get a competent shop to do it.

Replace any aluminum banjo fitting seal washers with copper. Copper seal washers can be annealed before reusing when in a bind if new seal rings are not available. Aluminum sealing washers cannot be softened and reused. To anneal copper seal rings, use a propane torch and gently heat the seal ring to dull red temp then allow to air cool. Annealing the copper seal rings before reuse, is required because copper work hardens when iinstalled and unless softened by annealing, may not reliably seal again. If new copper seal rings are available, that is the proper best practices reason to always replace used copper seal rings with new.
Copper banjo fitting seal rings are superior in every way compared to aluminum, and will withstand a lot higher pressures than aluminum seal rings. Copper also aids disassembly with an anti-seize property. Aluminum can corrode and seize the banjo bolt in the fitting, through the same corrosion process that often seizes the front upright upper control arm ball joint pinch bolts.

[eljay]

Replace any aluminum banjo fitting seal washers with copper. Copper seal washers can be annealed before reusing when in a bind if new seal rings are not available. Aluminum sealing washers cannot be softened and reused. To anneal copper seal rings, use a propane torch and gently heat the seal ring to dull red temp then allow to air cool. Annealing the copper seal rings before reuse, is required because copper work hardens when iinstalled and unless softened by annealing, may not reliably seal again. If new copper seal rings are available, that is the proper best practices reason to always replace used copper seal rings with new.
Copper banjo fitting seal rings are superior in every way compared to aluminum, and will withstand a lot higher pressures than aluminum seal rings. Copper also aids disassembly with an anti-seize property. Aluminum can corrode and seize the banjo bolt in the fitting, through the same corrosion process that often seizes the front upright upper control arm ball joint pinch bolts.

I agree that copper is superior.

My issue now is that I believe the seals are part of the banjo bolt and line assembly and the whole hose with banjo bolf and seals comes together as a package and is meant to be replaced each time it's removed from the caliper. So, if I remove the hose, I will have no way to stop the fluid leaking (since the banjo bolt cannot be removed with seals on both sides) while I replace the caliper. What's worse is that I won't be able to replace the seals. Feels like a never-ending circle that leads to the inevitable: replace everything with new OEM stuff, which is a very expensive proposition. The other option is Option #2 from above to cut and flare or completely replace the hard brake line leading to both rear calipers. Fun.

Here's what I mean by the seals being integral to the banjo bolt besides there being no separate part number for the seals (see here):
OEM:



Aftermarket (Febi):