copper brake lines

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John Frederick Cockrem
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copper brake lines

Post by John Frederick Cockrem » Sun Dec 13, 2015 4:13 pm

A few of us down here in Vic Australia were discussing copper brake lines as fitted to most English cars of the T series period, and of course fitted to our beloved TABCs and TD Tf and MGAs as well.
Anyway copper brake lines are now unroadworthy in Victoria because somebody reckons they can split.
In 50 years of messing around with these cars I have never heard of it happening and neither have any of my MG
friends
Wonder if any of my fellow enthusiasts in the MG T world have heard go one of our cars splitting a copper brake pipe.

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Marv
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Re: copper brake lines

Post by Marv » Sun Dec 13, 2015 6:47 pm

Is this a result of Aussie Politics and Politicians getting involved in something that they know absolutely nothing about? If so, it must have been a slow day in Parliament when they thought it up. Never heard of it happening on any Brit cars here. What do they feel the alternative material is to insure your safety?

Anyway: Some technical stuff, Given that DOT 3 Boils at 205 °C (401 °F)(dry), 140 °C (284 °F)(wet)
and DOT 4 Boils at 230 °C (446 °F)(dry), 155 °C (311 °F)(wet)! Quality standards refer to a brake fluid's "dry" and "wet" boiling points. Wet boiling point, which is usually much lower (although above most normal service temperatures), refers to the fluid's boiling point after absorbing a certain amount of moisture. This is several (single digit, usually 3.7 to 5.0) percent, varying from formulation to formulation. Glycol-ether (DOT 3, 4, and 5.1) brake fluids are hygroscopic (water absorbing), which means they absorb moisture from the atmosphere under normal humidity levels.

With that out of the way: I don't know what Abingdon used on the T-ABC's, probably copper or steel, but since the introduction of Copper-Nickel annealed tubing in the 60's and 70's and the fact that most of our cars have had at least one replacement of brake-line tubing since they rolled off the line, it is safe to say that CU-NI tubing was used and is all you can buy from the usual suppliers. (Don't get it from the local hardware store, that's copper, not CU-NI.

Data from the COPPER DEVELOPMENT ASSOCIATION in their technical publication CDA Sheet 49 (1990) shows data in attached file for 3/16" diameter CU-NI tubing.

Typical brake line pressures during a stop range from less than 800psi under "normal" conditions, to as much as 2000psi in a maximum effort. Unless you have a high performance vehicle with power boost, etc., you are not likely to see 2000 psi on a TC or many other pre 50's cars for that matter.

From the table provided you will see that a 90/10 CU-NI 3/16" annealed brake line tubing assembly has a burst pressure of 19,000psi or 130 N/mm2s. Typical factor of safety for life support systems is 2.5 to 1 yielding a working safe pressure rating of 7,600 psi. This would be typically at 100°F. A downgrading of psi working pressure occurs with temperature rise by as much as 30% or 40% up to the boiling point of the fluid being used. This yields a working pressure at temperature of 4,560psi, which is still well above the braking pressure our systems can generate by a factor of two. If, for some reason, your system reaches the boiling point, it's not the lines that will fail! The seals in the M/C and brake cylinders will fail and you will have a total system failure with no brakes whatsoever.

Now, what does all this prove to the clerk at the local DMV, or fat-back politician? Nothing! You'll probably still lose your appeal. Maybe the fact that it can be classified as a "Historical Antique Vehicle" or that the only materials available for repair are CU-NI will save the day.

Long winded answer but interesting to those who care maybe!

Marv TC5141
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Brake line characteristics.jpg

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frenchblatter
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Re: copper brake lines

Post by frenchblatter » Sun Dec 13, 2015 10:34 pm

Marv, CU-NI will fracture. Nothing to with the the science. If it's not clipped at close regular intervals the slight movement induced will fracture it. I seem to remember the suggested clamping is 12", 200 cm apart. The TC is clipped well enough not to cause any problems.
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John Frederick Cockrem
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Re: copper brake lines

Post by John Frederick Cockrem » Mon Dec 14, 2015 1:58 am

Many thanks for your reply Marv, very technical for an old bloke like me but it backs up the "Ive never heard of it happening" comment I am getting down here. Wouldn`t mind sharing one of those Old Specs with you Marv, very good brew for a TC punter

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Marv
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Re: copper brake lines

Post by Marv » Mon Dec 14, 2015 2:35 am

Norm Verona wrote:
Marv, CU-NI will fracture. Nothing to with the the (sic) science. If it's not clipped at close regular intervals the slight movement induced will fracture it. I seem to remember the suggested clamping is 12", 200 cm apart. The TC is clipped well enough not to cause any problems.


Norm, I don't believe John's question had anything to do with fracturing due to improper "clipping" which, by the way, has everything to do with the science. It's called "metal fatigue"! All materials have a fatigue strength rating based upon a number of factors surrounding their physical makeup. A piece of uncooked spaghetti clipped in enough places isn't likely to fracture on the rail of a TC in use either. But ,spread the clips out far enough and it won't last a mile in all probability. CU-NI has a very good fatigue strength rating and isn't a candidate for fatigue failure on our little cars!
Properly "clipped" of course! :)

Marv

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Marv
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Re: copper brake lines

Post by Marv » Mon Dec 14, 2015 2:48 am

John:
Been down your way a number of times for the company when I was in my pre-retirement stage of life. Also, took my better half once for about a month as well. Spent 17 days up in the Snowy Mountains looking for the remains of Ned Kelly and any loot he may have stashed. No luck there! Did the Snowy Mountains infamous "Pub Crawl" where a number of your countrymen had their fun giving us all the wrong directions to the next Pub on the list after we had had a few pints with them. If I head that way again, I'd like nothing better than to have an "old Hen" or two with you!

Marv

John Frederick Cockrem
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Re: copper brake lines

Post by John Frederick Cockrem » Mon Dec 14, 2015 7:12 pm

Marv and Norm
A mate just advised he had an original copper line let go about 40 years ago and he reckons it was well clipped.Any thoughts on the original material because a lot of cars including mine are still on the orig pipes
Marv you would have been battling to find Ned as the Snowys are a long way from what we call "Kelly Country" which is around the Mansfield Benella area.In fact Glenrowan where Ned was caught is just up the road from Benella. Pardon the history lesson but if you come back on the search………...

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Re: copper brake lines

Post by frenchblatter » Mon Dec 14, 2015 9:39 pm

Marv, In the UK the building control people have banned the very thin multi-layer roof insulation material in new houses. Not because it doesn't work, it works extremely well, but because it has to be overlapped and sealed properly and a lot of builders weren't installing it correctly so they banned it;s use.

I understand metal fatigue is part of the science. You quoted strength not an indirect cause of failure. I have no idea why it's been banned, only offered a suggestion. I know several F1 design people who wouldn't use it because of it ability to crack.
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Marv
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Re: copper brake lines

Post by Marv » Tue Dec 15, 2015 8:05 am

John Frederick Cockrem wrote:
A mate just advised he had an original copper line let go about 40 years ago and he reckons it was well clipped.Any thoughts on the original material because a lot of cars including mine are still on the orig pipes....?
John:
The short answer is No! The long answer is below as to why the short answer is "No"!

I have looked through a number of my old technical references with little luck on 30's and 40's copper tubing UK and USA standards. I have found that the first copper tubing made for automotive use was just starting to be produced in the late 30's and early 40's. From this, I suspect that earlier brake line materials were steel of some composition that I cannot find reference to. Copper tubing for household pressurized water systems was first introduced in the late 30's but didn't find wider usage until some 10 years or so later. Specifications from either side of the pond are hard to find for regulations and use in that time period. So we don't know what the manufacturing process was (drawn, Annealed, extruded, etc.). Nor do we know what the material composition was, if any, other than soft copper. It certainly was not copper-nickel in the day as that did not come into wide acceptance and usage until the '60's.
The oldest reference to copper tubing in the UK for maximum working pressure recommendations. For 3/16" soft copper tubing of the time, the figure was 700psi at 100°F. That would be an estimated burst pressure of about 1750psi at 100°F. Well below the CU-NI ratings of today's copper lines. Copper of the day also did not have the galvanic inhibitors found in todays copper plus the brake fluids of the day did not have the same type of inhibitors for water absorption or anti-corrosion as we have now either. A mixture of steel fittings, clips and other factors also would have a negative effect on life expectancy. That's all I found of any relevance to your question.

An interesting tidbit was found in somewhat typical UK English technical writing (i.e. ...."assembly is the reverse of disassembly!") It is:

Tips on preparation and installation of copper brake tubing
"Preparation"
1. Determine the length of brake tube using engineering drawing, string, flexible tape or the old brake tube as a pattern.
2. Cut off the required amount using a cut off tool or a fine tooth pitch hack saw ensuring that the sawn ends are square. DO NOT distort the tube or damage it by over-tightening in a vice.
3. The sawn faces should be dressed to remove burrs from the outside edges. DO NOT allow slivers of metal to enter the tube.
4. The appropriate single or double flare can be formed using a good quality flaring tool. DO NOT use worn punches or dies.
5. Ensure the tube is gripped securely without deforming the tube section or indenting its surface. DO NOT use serrated grips.

"Installation"
1. The nutted and flared tube should be bent carefully into shape so that it will fit easily into position. Use of a wooden form or proper bender tool is recommended over hand bending. DO NOT kink or strain the tube into position. It should emerge cleanly from the nut without bearing against it.
2. Bends should be smooth and have a radius of at least 3 x tube O.D.
3. A straight in length of 1-1/2 nut lengths should be observed prior to the bend for easy installation and removal of fittings.
4. A small quantity of brake fluid on the bearing surfaces of the flare will ensure that it and the nut can be tightened without twisting the tube. DO NOT overtighten the nut. From hand tight to full tight should generally be between 1 and 1-½ turns.
5. All brake tubes should be supported at regular intervals along their length using either steel clips with a resilient rubber lining or by the clips each attached to the body or the chassis of the vehicle. When tube runs follow the axle casings or suspension arms which can induce vibration of the tube, adequate, secure fixing is essential. Clips should be spaced at least at the recommended distance for steel, although a spacing of 12" - 13" is preferred for copper tubing.

Not much help and probably more than any of us care to absorb for any time length. I gotta' protect what grey matter I've got left for more important things.

On the Snowy Mountains and Ned Kelly, we actually stayed at a lake resort more toward Mansfield in between the two areas. As I recall, it was only about a two hour drive to "Kelly Country" from the resort and the same to get into the Snowy Area going the other direction. We did visit the overlook area where Ned was supposedly caught in one of his hideouts.

Cheers,
Marv....

John Frederick Cockrem
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Re: copper brake lines

Post by John Frederick Cockrem » Tue Dec 15, 2015 8:28 pm

Marv, Very informative and appreciated. Old Ned! My grandmother used to talk about his sister Kate quite a bit who is buried in the Forbes cemetery ironically not far from Ben Hall (another bushranger) Grandma was Irish and her father an Irish cop was involved in the Kelly hunt although he was based in Geelong. His name was O`Dwyer

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Duncan M
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Re: copper brake lines

Post by Duncan M » Wed Dec 16, 2015 5:49 pm

John-
You mean your Gov't has declared a law against copper appearing brake lines? Outward appearances can be deceptive.
Last edited by Duncan M on Sun Jan 14, 2018 10:15 pm, edited 3 times in total.

John Frederick Cockrem
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Re: copper brake lines

Post by John Frederick Cockrem » Wed Dec 16, 2015 10:39 pm

G`day Duncan,
Thank you for your interest and comment. Yep copper brake lines are unroadworthy in the state Of Victoria but not sure of the other states.Not sure re the cupric stuff though. Yes I have had hard drawn 1/2 inch copper pipe split in our house, and my plumber mate who fixed it reckoned it was a dodgy batch which crept through down here in the 1970s.Never an issue with annealed stuff in the home though. Do you have any idea of the composition of the tube used in our cars?Marv didn`t seem to know and he certainly did his homework on this topic. I am with you on this issue given I have only heard of one failure in 1978. Stick with it as there seems to be plenty cars running `round with the original pipes including Phil Cassie`s TA and thats pretty darn old!……sorry Phil !

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Re: copper brake lines

Post by frenchblatter » Wed Dec 16, 2015 11:29 pm

Is that Phil or the car that's old?
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John Frederick Cockrem
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Re: copper brake lines

Post by John Frederick Cockrem » Thu Dec 17, 2015 10:18 pm

Good on ya Norm,Both old ,and he`ll kill me when he reads this! I`ll make him happy by saying its a lovely TA that I have spent many happy miles in while navigating "Old" Phil on various VSCC events!

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ian theobald
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Re: copper brake lines

Post by ian theobald » Wed Jan 06, 2016 10:44 pm

G,day folks. I replaced all my pipes about a year ago and actually wrote to NSW RMS as was not sure if the copper nickel pipes were legal.
The reply I got back was the usual ADR stuff but lastly Steel Bandy pipe meeting some design rule but more importantly last paragraph stated or other type pipe that was equivalent.
The Cunnifer pipes sold over seas had an equivalent safety rating as the Steel ones. [ISO rating ] so I guess pipes would be stamped such as brake hoses for motor bikes having to meet standards
Having said that I went ahead and purchased steel pipe flaring tool ,pipe bender and made my own pipes and then sat and wound by hand tie wire around to make look authentic.
Very rewarding as most brake places were not interested.
Was hard to double flare but got there in the end.
I got good pictures from Doug Pelton as to correct routing.
My cylinders had Brass sleeves so only required honing but my Master cylinder was shot so purchased a new one.
As for hoses they looked perfect but were actually clogged completely so replaced as well.
My brake line looked perfect but with all new brake power actually tore one shoe off old bonding so have replaced all of them.
Funny enough brakes are only slightly better but don't fade now down the mountainous road locally here on the South Coast of NSW [Nowra ]
I will try and find copy of e,mail that roads authority sent but even local garage said that if originally fitted was ok. My old pipes were badly kinked possibly bent by hand . Also will dig up old photos .

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ian theobald
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Re: copper brake lines

Post by ian theobald » Wed Jan 06, 2016 11:06 pm

pictures of my hand wound brake pipes
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ian theobald
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Re: copper brake lines

Post by ian theobald » Wed Jan 06, 2016 11:09 pm

If you look carefully you will see my later type diff that someone fitted at some stage . Ends have been cut off and welded to original TC fittings

John Frederick Cockrem
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Re: copper brake lines

Post by John Frederick Cockrem » Fri Jan 08, 2016 11:13 pm

G`day Ian, Good to hear your story and you have done a great job on the replacement pipes,you must be very patient doing that winding! Begs the question , can you clean up and use the orig windings? I do remember many years ago using a fly wire door return spring as a covering and it worked a treat.I don't think you can get em now,
but perhaps a spring works could help with something???!!!Your comment re improved braking was interesting, and yes ,bad flex pipes can cause problems with the car darting all over the place!Been there done that!
Anyway are the old copper pipes legal in N.S.W ? certainly not in Vic but I have only heard one instance of a failure down here in 50 odd years of driving T types. Have you heard any negs up your way?

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ian theobald
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Re: copper brake lines

Post by ian theobald » Sun Jan 10, 2016 1:20 pm

G,day.Not really sure but if original ,should be legal as rules ADR applies to all states but then again the TC pre dates any modern rules which I think came into effect 1976.
I purchased a cheap pipe pending tool which I have no use and a pipe flaring kit and pipe cutter and purchased the steel pipe in a roll from local bearing supplier.[What else can you do when brake places could not even give a quote]
I was told that you can soften this pipe after with heating to make double flaring easier but of the dozen or so ends that I flared only had to redo one.
I found out later with the pipe cutting tool that can be reversed so faulty end can be cut off with minimal wastage so bests to allow slightly extra in pipe when folding.
My old pipes were routed incorrectly under car so had to use pictures as a guide [see from the frame up tech guide as gives exact length of each pipe ]
Winding wire was easy but bit time consuming and have plenty left over [thin gal wire used for tying reo bar]
No worse than knitting.
I,m sure if you flick an email to Vic Roads technical enquiries about later type Cunnifer pipe will get similar answer as can purchase as a kit but still have problem of bending correctly and if a mistake made then wasted a pipe.
The steel pipe is easy to bend and if you have a pipe to copy even better.
If you intend to replace pipes
I can post pipe tools down if required but all up with pipe and tools was less than $200 I think.
Honing cylinders was another easy job.
Don't do what I did and clean master cylinder container with CRL remover.
Sure it cleaned spotless inside but held up to light and could see little silver flecks which I thought were solder ,In fact was daylight so purchased a new one with stainless container from Sports Parts MG in Sydney.
My old M/C was brass sleeve also and still have but container has pin holes.
In Summary quite an easy job to do and would not toss and turn about steel versus copper nickel. With wire wrapped around no one can tell and we don't have salt on roads to worry about ,just lots of gravel
Original pipes I believe were thick walled copper but I,m not sure if the same grade as what is available now.
In all honesty never known any garage to check ,especially on an old car such as a TC .
Also purchase pipe spanners so you don't round nuts off as old ones will no doubt be tight and large ring spanner for nut behind Master Cylinder .Can, t remember what size but could not fit a shifter in that area and think I used a large metric one .
Good luck Ian

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Steve Simmons
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Re: copper brake lines

Post by Steve Simmons » Sun Jan 10, 2016 1:38 pm

Cunifer tubing can be bent easily by hand. And for anyone doing this job in the future, Roger Furneaux sells stainless coil as original (except for the stainless part) ready to slip on.

Here are the lines I made from Cunifer, with Roger's coil, and some custom stainless flare nuts. The flats are longer than stock to resist rounding. Original example on top.
Attachments
brake-lines.jpg
1949 TC8975 / XPAG 9609
1948 TC6011 / XPEG1182 (XPAG6472)
http://www.mgnuts.com

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