Thread: Plumbing the chassis

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This is a sore subject with me and it is not over yet. First, the Speedway 37 degree flare is junk, mine broke on about the fourth flare of stainless tubing. Second, IC2 is correct that stainless work-hardens and what ever you do at first is it, there can be no corrections. Third, of course, put the fittings on before you flare both ends! I am no expert here, just a frustrated first time user, although I did work on an assembly line flaring many copper tubing connections in a refrigeration manufacturing plant. After several failures and split ends even on single flares I measured all the lines needed and took the tubing and fittings to John York who has a nearby shop building turnkey Cobras. John did a great job using a very old surround clamp in a vise and tapped down on the ends with a dimpling tool for a double flare. With a little patience and persistance I got almost all the lines sealed but I just could not stop a leak to the left front wheel at the tee. I replaced the tee and the line but still the second line leaks at the tee. I tried adding a short wrap of teflon tape on the joint but it still leaks "a little". This is an unacceptable situation but I have postponed replacing it a second time and will have to fix it before driving! In the back of my mind I think I will have to take the car to John York's shop and see if he can replace it again and get a seal. Soooo, the question is do you really want/need stainless? If you get it right, it is forever, great! I have looked at the end which leaked and the flare did not crack, it just seems to be slightly assymetric in the AN fitting so I suppose/hope that if I keep replacing that line I will eventually get it right. On the other hand you could use precut steel lines with the ends already flared from an auto supply shop and paint the lines and be good for ten years. As I see it a first timer should use ready made steel lines OR pay a pro to do stainless lines. I thought my experience with flaring copper lines would make working with stainless an easy job, but stainless is tough to learn on. Now I am stuck with this leaking line and I guess the main thing to do is to make sure the double flare is symmetric in the AN fitting. For the record, John York assumed that 37 degree stainless should be doubled-flared.

Don Shillady
Retired Scientist/teen rodder

Originally Posted by Don Shillady

This is a sore subject with me and it is not over yet. First, the Speedway 37 degree flare is junk, mine broke on about the fourth flare of stainless tubing. ........

For the record, John York assumed that 37 degree stainless should be doubled-flared.

Don Shillady
Retired Scientist/teen rodder

Don,
I agree with you about the Speedway 37* flare tool - I went that way first then spent the big bucks.

SS is really not tough to work with as long as you understand what has to be done. It is a bit difficult to bend as tightly as CS as it is harder material and has some spring back. I would run, not walk away from your buddy when it comes to working with SS brake lines as he doesn't, to me, have the tools. If it's cut square, and the tool is in good shape, there should never be an asymmetric flare. The tool I show above will run the flare down to the proper size then "breakaway" so you don't over do it.

Using the tools pictured above, I made all of my connections (lots of them) and had one minor seep at the proportioning valve and one at the MC which I corrected with a bit more tightening. The system was filled about a year ago - and ten minutes ago - no new leaks.

Unfortunately auto supply shop lines come in pre cut lengths and have never been "just the right length" for any car I have ever done.

Originally Posted by IC2

This $585 thin wall tubing tool you show a link is for copper and aluminum only according to the information. You cannot safely use either metal for tubing brake lines on an automobile. Try to double flare with SS and you will split it around the circumference of the bend fold. Why would you even want to consider double flares in AN fittings that are designed for and only require a single flare?

If you read my first post you would see I never suggested a double flare for an AN fitting. I stated "It can be double flared but it is not necessary or advisable"
The tool I linked to was only to show it is possible and there is a spec for a double flared AN nothing more.

Originally Posted by DennyW

I'm sorry Chuck, but that's not what I read... They will also split.

((Originally Posted by IC2
You cannot use a double flare with AN fittings - they will not fit the sleeves.))

I would have to disagree.

It is almost impossible to do it most flaring tools, but it can be done. HERE is a tool made for 37deg double flares to AN standards. Not the kind of tool you find in most garages.....

Not 500+ dollars for the home mechanic either. That's why you buy lines already done, if you go stainless. Same as exhaust pipes on the bends.

Why would you want to double flare SS brake lines for fittings that weren't made for it. 3/16" SS tubing will crack when you fold it over. If I was to use standard Bundy carbon steel brake tubing I would have double flared the ends using my double flare tool (not shown above) and the proper 45* fittings

There is no way that I could have bought pre made brake or fuel lines for my car. That's why I bought the good Rigid SINGLE, 37* tool kit.

Exhaust tubing - again, no way to buy a pre made exhaust system for my car. It's a welded system with a few slip joints, using 'U' and 'J' bends and a length of aluminized steel exhaust tubing

At this point I have enough leftover tubing to try a single flare or two; it does look like there is more material to overlap the nose of the male part of the AN connector. I think when you use a double flare the ridge is stronger but more narrow with less chance to fully cover the nose of the male connector. On the other hand it looks like I will just have to try and retry until I get it right.

Don Shillady
Retired Scientist/teen rodder

I hadn't thought about using pre-made lines, but I would likely need to cut one or two and then flare it and at that point I may as well just do them all maybe.

so how bad is the steel line then? I had only thought of it rusting out due to road conditions and not as much just sitting. They rust on the inside and out? Come to think of it, one of the brake lines on my 10 year old Blazer rusted out, but it had a few owners up north and is all rust on the bottom. How much do I have to worry about using steel line? not only does stainless cost twice as much, but it sounds like it's harder to work with and I have yet to save money on any part of this car is this a possible place to cut costs without paying more in the end?

the braided lines W/O DOT on them...are they legal or should I avoid them altogether?

Thanks

yes the steel will rust from inside and out. you could combat this by replacing your brake fluid once a year or at least every 2 years as you should... Even if you use SS lines its very important to change the fluid regularly...... I think they offer some synthetic brake fluid also.

I guess I just have too much faith in OEMs using steel. I'm having a hard time in general distinguishing overkill/waste of money from the essentials. If stainless is that much better that's what I'll do...stainless, single flare, AN fittings, right?

IMO steel is fine..... With yearly maintenence you will be fine for years and years. Like I said even with SS you need to replace the fluid regularly the brake fluid will still attract water causeing brake fade over a period of time.

You can use CS and of course it's your choice. My reasoning for SS was twofold, The first being survivability from all conditions and a lower maintenance factor. The second is appearance on my TCI Stage 3 chassis which has mostly chrome and stainless components.

With the first reason, fluid changes can be extended another year or so with an extremely high grade brake fluid - I'm using ATE Super Blue Racing Class 4 fluid which has a very high boiling point and has a very low water absorption rate. I will not use silicone fluid even though it does not absorb much, if any air borne moisture. It has some compressibility which leaves you with a less then solid brake pedal. You will hear some with argument that go like this: " I've used silicone brake fluid for xx years in my Turmoil Mega 9 and never had any problem". He's often right - but that spongy pedal in some cars leads to less then satisfactory braking performance.

OEMs use CS brake lines and Class 3 brake fluid for a simple reason - cost. I've replaced many brake lines on daily drivers - and in my area, that can be in as little as 5-6 years. The highway departments use salt on the roads for winter ice removal - it doesn't go away in the summer - it's driven into the road surface and sits there just waiting for that nice bare steel to rust away.

If you are doing brake lines on a street rod, that is the one place not to have less then the best available.

DOT marked flex hoses will pass your state inspection. If you have a sharp inspector that catches this omission, he my fail you - which means tow it/drive it back home, install new DOT flex lines, new fluid, add a bunch of time and costs then return for another inspection.

OK Dave/IC2, I have checked with a local shop building drag race cars and they use regular steel lines, probably because their lifetime is measured in terms of a racing season or less. Locally I will have to look around more in the local industries supporting the nearby airport to find a 37 degree flaring tool for AN fittings other than the one at the Cobra shop which does the double flare. So are you saying you used SAE fittings with a 45 degree flare on stainless tubing? If so I am sort of stuck with the AN fittings and still looking for a single 37 degree flaring tool. So can you define what you have as:

1. stainless tubing?
2. single 45 degree flare?
3. SAE fittings?

Don Shillady
Retired Scientist/teen rodder

Originally Posted by Don Shillady

OK Dave/IC2, I have checked with a local shop building drag race cars and they use regular steel lines, probably because their lifetime is measured in terms of a racing season or less. Locally I will have to look around more in the local industries supporting the nearby airport to find a 37 degree flaring tool for AN fittings other than the one at the Cobra shop which does the double flare. So are you saying you used SAE fittings with a 45 degree flare on stainless tubing? If so I am sort of stuck with the AN fittings and still looking for a single 37 degree flaring tool. So can you define what you have as:

1. stainless tubing? YES
2. single 45 degree flare? NO - Single 37* flare
3. SAE fittings? NO - AN, mostly -3

Don Shillady
Retired Scientist/teen rodder

Don,
Hope I didn't confuse you too much . The only SAE fittings on the car brake system are adapters to AN at the master cylinder, residual valves and proportioning valve. My fuel system is also completely SS with all AN-6 fittings

IC2, Thanks, I just located a place here in Richmond that does 37 degree stainless flares so I will try that out on my leaking connections. Surprisingly the nearby airport mechanics say they use aluminum tubing to save weight and because they deal with lower pressures than in brake lines. Maybe I will get those leaks fixed yet!

Don Shillady
Retired Scientist/teen rodder

do auto supply stores sell flared stainless line or just steel? I am thinking about getting some pre flared line to at least minimize possible leaks due to my amateur flares. if i have to cut a line or two I will just have less connections to worry about leaking verus doing them all myself. you guys have started to scare me with these leaks

Originally Posted by 35fordcoupe

do auto supply stores sell flared stainless line or just steel? I am thinking about getting some pre flared line to at least minimize possible leaks due to my amateur flares. if i have to cut a line or two I will just have less connections to worry about leaking verus doing them all myself. you guys have started to scare me with these leaks

Not that I've seen, at least anywhere I've lived. Stainless is not a standard item though you can buy exactly the same 6' line lengths from McMaster Carr that Inline Tube sells

Master your tube flaring skills with standard CS line, then move on to the SS. If you have good tools, no big deal. Denny's post above is an excellent guide on how to do this.