brake lines

[MiataPaul]

I pulled my 1991 Subaru AWD 5Spd Legacy out of it's summer slumber (winter replacement for the Miata) and found it to have a leaking brake line. I have not found the exact leak location, but the fluid flows over the gas tank on the passenger side. How hard is this to fix, It looks like i Will have to drop the gas tank, and that looks like removing the exhaust, and drive shaft. I have a 92 fwd 5spd legacy that I am parting out, would the brake line from it fit? I have not had a chance to really look at it, but it looks like a lot of work, and I am broke so taking it to someone is not an option. I was so hoping it was a flex line as it would be a 5 min fix.

[BAC5.2]

I wonder if you could cut the hardline, flare it, and use a flare nut and some SS line from Earls, and run that to the Caliper?

I bet it would work, but it'd require some work on your part.

Just an idea.

[vrg3]

I was going to suggest the same thing... It'll cost a lot but it'll be much easier to handle.

You can reuse your existing flare nut.

So you could start by undoing the joint between the hard line and the rubber hose in the wheel well.

Then, you could cut the tubing and remove the flare nut.

Then, you could cut the tubing upstream of the leak, put the flare nut on, and double-flare the tubing.

Then, you would need to get an appropriate fitting to go to -3 AN, like maybe Earl's part number 989545:

http://www.holley.com/products.asp?product=989545ERL

Then you'd need a -3 AN stainless steel brake line of the appropriate length:

http://www.holley.com/types.asp?type=252

And then end it with an adapter to go to a 10mm banjo (which attaches directly to the brake caliper), like maybe 997603:

http://www.holley.com/products.asp?product=997603ERL

I'm not entirely sure each of these parts is exactly what you'd need, but you get the idea.

Or to do it a little cheaper, maybe you could find a local shop that makes custom brake hoses, and have them make you a long one with the right M10x1.0 fitting on one end and the 10mm banjo on the other end. I don't know if there would be an issue with having that much rubber.

[Psychoreo]

i love it when you post vrg3... now everyone has detailed instrustions on exactly what to do. no telling how many times your vaccuum line diagram saved my ass.

[vrg3]

=)

Good luck... if you try this approach let us all know what actual part numbers ended up working.

Also, another suggestion -- you might try searching for NuwanD's old posts on his brake line modifications; some of his suggestions may be helpful. For example, he suggests using a Dremel with a cutoff wheel rather than a tubing cutter, because a tubing cutter work hardens the steel which makes flaring difficult.

[professor]

just cut out the bad section, fashion a suitable length of replacement tubing into the same shape as the removed section, and put it into place with compression/compression fittings on each end

no flare tool needed, and you keep the end of the line and the flex line without even removing it. cut where you can access it wel enough to tighten the crap out of the fittings with two wrenches. a tubing wrenches will help get the best bite

Cost: $5 for two compression fittings, $5 for a foot of line at you local parts store, time, 1/2 hour at most

I would NOT do this on a front brake line but in the rear safety is not so much of an issue

[vrg3]

Even if he could easily access the location of the leak, they say you're never supposed to use compression fittings on brake lines. I'm not exactly sure why, though -- are compression fittings less reliable than double flares? Or are they not as suitable for high pressures? Or is it that they're not reusable?

Why is safety not so much of an issue on a rear brake line? No matter where a patch job is in the brake system, if it fails it'll take out at least one front and one rear brake, won't it?

[professor]

a crappy compression fitting may not have the rating suitable for brake lines, but a good one will

better brass ones are rated for 800 psi, and steel ones for >2000 psi.

I think it is the fool who would go to the hardware store and buy the compression fitting suitable for the toilet, that led to that "rule"

mcmaster.com has a great selection of fitting that should work fine, brass high pressure, and steel if you want to over-do it. A local supply house may have them cheaper

no I do not think a flare fitting would seriously out-perform a 2000 psi compression fitting. I suppose the issue is slippage of the line, but if you've ever dissected a good connection after tightening, the ferrule puts a big enough kink in the line to make slippage just about impossible.

IIRC braking pressure is about 500 psi, and I would go for the steel

[vrg3]

Hmm... it was my understanding that under emergency braking conditions line pressure could exceed 1200 psi. But it does seem McMaster carries some brass compression fittings meant for hydraulic lines that's rated to pressures significantly higher than that.

But still -- you wouldn't do this on a front line? Isn't it just as unsafe to do it on a rear line?

[professor]

yeah it really wouldn't matter which line goes, 1/2 your braking diagonally is gone.

new line is really cheap, I've replaced it on several vehicles, although they were almost completely disassebled at the time making the swap simple. I recall paying something like $25 for four lines once, with flares and nuts. is it really that hard to get a new line in there ? its too cold for me to go out and lay on the ground right now and look

[MiataPaul]

The design of the Subaru master clynder does not really isolate the 2 circuits very well, IMHO. There does not seem to be much of a dividing wall to seperate the two halves. once one side leaks down it just draws out most of the fluid from the system. There is not really enough fluid left to operate the other side efficently. How do I know?, the above broken line left me with no hydrolic brakes and I had to rely on the parking brake to get home. Good thing it was at 1:00 AM on back roads with no traffic. I don't think I saw another car the whole 10 miles home.

[MiataPaul]

One other thing, what is the size of the brake line? will i need to know this when I get the replacement line. They sure look thiner than the lines on my MG that I had to replace one of the front lines, but that was a flaired fitting, and it was all open. How I miss the simplisity of that design, to bad they were so poorly made.

[Legacy777]

Brake pressures can reach +1000 psi under extremely hard braking. The rear "shouldn't" see those pressures due to the proportioning valve.

However if you decide to do the compression fitting, I'd go for the steel 2000 psi fitting.

Check out the split point data
http://www.main.experiencetherave.com:8 ... kemath.xls

The medium & heavy braking notes I have on there were put in based upon pedal input force and related to the info in the FSM.

[BAC5.2]

I also noticed that the "diagonal" braking thing was bullshit.

I lost a drivers side rear brake, and all 4 went out on me. Car wouldn't stop to save my life.

[vrg3]

Hm.

I wonder if we should explore swapping to a different master cylinder design or something.

[Manarius]

Hm.

I wonder if we should explore swapping to a different master cylinder design or something.

LOL We could go to something the size of my vette...it's the size of a small pumpkin

[Legacy777]

Hm.

I wonder if we should explore swapping to a different master cylinder design or something.

Actually it would mean you could do away with the diagonal circuit, since it doesn't work, and use an adj prop valve

[vrg3]

Manarius - I was talking about the master cylinder... I like my current brake booster.

Josh - But I'd like to actually have the protection of dual diagonal brakes.

[professor]

>>>I also noticed that the "diagonal" braking thing was bullshit.

and also explains why bleeding is such a pain in the arse. If you open one line, you may draw air into all four, instead of just two

[MagicBus]

Sorry to bring an old topic back from the dead, but this is relevant to my latest problem. A couple of weeks ago I bought a '95 Legcacy L wagon (2nd generation, I know, but I think that shouldn't make a difference for my question) to replace the VW Jetta I bought in November which in turn had replaced my '94 Legacy L.

Anyhow, yesterday on my drive home, I lost my brakes. Was able to avoid hitting anything and coast into a gas station parking lot and wait for a tow home. Diagnosed it tonight as a rusty steel line going to the passenger side rear caliper.

As previously mentioened in this thread, the line to that caliper is routed over and above the gas tank and rear subframe. This will be my first time replacing steel line, and I want to do it as safely as I can.

Everything I've read so far online tells me to duplicate the original line as closely as possible with respect to bends and whatnot. Why is that? Would it hurt anything if I routed the line UNDER everything yet safely out of the way of moving stuff?

Why do people say to duplicate the original line as closely as possible?


Also, from what I've read so far, it looks like these cars use double-flared line? Is that correct? Also, does anyone know offhand what diameter line is needed?

[Legacy777]

Yeah, I'm pretty sure it's a double flared connection. Make sure you do your flaring properly, or it will leak.

As for why running it the same as the stock line. Why not? Personally, I'd want the brake line out of the way to minimize any damage, but there's no reason why you can't run it under everything.

[MagicBus]

Thanks for the reply.

Actually, I was able to fix it this past weekend. With the rear subframe and gas tank in the way, I couldn't see a way to route the lines as original, so I rerouted the new lines as out of the way as I could (being careful, of course, to stay away from the exhaust and anything that moves). Also replaced the rear flex hoses, the bleeder screws on the passenger side (took forever to free all of them up) and did a full fluid flush.

Approximately 350 miles on the repairs already with no issues I've seen. This was my first time flaring brake line, but I took my time, went slowly, and am pretty sure I have good connections.

[Legacy777]

Good deal. Glad you got it figured out.