View Full Version : Is it OK to use copper tubing for transmission cooler lines?


Nealcrenshaw
02-17-2009, 01:13 AM
I know its easier to bend. Would it suffice? Or should i just use steel tubing.I'm going to replace them soon.

autoace
02-17-2009, 01:33 AM
Use steel tubing, copper my work, but I have never seen it used...the flares may be too soft with copper. depending on what the car is(most trans. lines are high pressure hose and steel line) the original equipment can be real cheap.

Nealcrenshaw
02-17-2009, 01:36 AM
How do you feel about fuel lines with copper? I know brakes are out of the questions w/copper.I appreciate the PM you sent the other day as well.

autoace
02-17-2009, 02:03 AM
How do you feel about fuel lines with copper? I know brakes are out of the questions w/copper.I appreciate the PM you sent the other day as well.

I wouldn't use copper for fuel line either, why? since I am a professional, I abide by "industry standards", and copper is not used. I've never discussed why they don't use it? It has not come up. With the exception of "hot rods" all vehicles need to have OEM repairs period, and for inspection purposes. If it is an aftermarket part on a street legal vehicle is need a C.A.R.B. exemption number, or other DOT approval, etc...depends on type of part.

A case in point (the thread about oil drain valves)they void a new car warranty, and no liable professional would use them on customer cars, so in my book they don't belong on a car. Now what people do to their own cars, is "kind of their business" provided it passes inspection.

autoace
02-17-2009, 02:13 AM
^^^
Remember Copper has a free electron in its outer shell,it conducts an electrical charge very well because of this, probably a simple reason it is not used anywhere on car plumbing. A bad ground somewhere and dangerous paths of current could flow where you don't want them to. I know steel is also a conductor, but no where near the affectiveness of Cu-

nissan_crawler
02-17-2009, 02:19 AM
I'm with the "why?" group. You can get new prebent lines for most cars at any parts store, and they're quite cheap.

Nealcrenshaw
02-17-2009, 02:57 AM
The reason i asked was when i used to work for an auto parts store
a few customers would order the copper tubing for fuel line 1/4",-3/8". They told me that it was easier to bend than steel line,which is true. So i didn't know that if some used it for fuel would it be ok for transmission lines.

autoace
02-17-2009, 03:05 AM
The reason i asked was when i used to work for an auto parts store
a few customers would order the copper tubing for fuel line 1/4",-3/8". They told me that it was easier to bend than steel line,which is true. So i didn't know that if some used it for fuel would it be ok for transmission lines.

For old cars with mechanical fuel pumps, it is probably safe, but it is not common practice. I speak from a liable, industry standpoint. My final answer is (I would not use it on your car, if I were doing the repairs).

Kevin54
02-17-2009, 03:22 AM
I wouldn't use copper for fuel line either, why? since I am a professional, I abide by "industry standards", and copper is not used. I've never discussed why they don't use it? It has not come up. With the exception of "hot rods" all vehicles need to have OEM repairs period, and for inspection purposes. If it is an aftermarket part on a street legal vehicle is need a C.A.R.B. exemption number, or other DOT approval, etc...depends on type of part.


I'm not an expert by a long shot but I would think that two reasons NOT to use copper would be for one that it is too soft and any debris from the road could damage it, and two, galvanic corrosion from mixing the metals.

Merkava_4
02-17-2009, 04:59 AM
I'm thinking I never seen a copper tube flared; they've always had those compression union fittings or whatever they're called. :dunno:

autoace
02-17-2009, 05:11 AM
I'm thinking I never seen a copper tube flared; they've always had those compression union fittings or whatever they're called. :dunno:

For propane lines they are single flared copper, trans. lines are sometimes double flared and I have never seen copper trans. lines.

komobu
02-17-2009, 05:55 AM
I started driving in '78. My first and second cars were both plymouths built in the late 60s. They had copper transmission lines. I remember it well because my first automotive fix was repairing a trans leak on it. I have seen copper used on many older vehicles for both fuel and transmission. I always thought the main reason for doing away with it was financial. (I could be wrong of course:-))

In the early 70s the value of copper went so high that they started using aluminum wiring in homes. If you can save 25 cents per vehicle, multiplied by the amount of cars built, the costs saving to the mfr can really add up.

Having said all that, I am not sure what the pressures are on late model automatic transmissions. I transmission guy might be able to better answer that.

Junkman
02-17-2009, 07:10 AM
Not all copper tubing is created equally. The refrigeration lines on my home air conditioner are copper, and they handle high pressure. The reason that copper isn't used on transmission cooler lines is because to get a hard enough copper line is more expensive than using a steel line that is already hard, and costs a lot less. If you need a prebent steel line, then check with www.inlinetube.com for your car application. They have them in both steel and stainless. Usually about $25 for both lines, and $10 shipping. If you have the ability to do good flares, then just buy the steel tubing and make your own. Steel is a bear to bend unless you have the correct tools, so that is why I buy mine prebent.

bigdav160
02-17-2009, 07:12 AM
Copper is not used because it easily work hardeneds with vibration. It's just a matter of time before it will fail.

StingRay
02-17-2009, 08:29 AM
I agree 100% with bigdav160 about the work hardening and a predisposition to fatigue however I work in the RV industry and all propane lines in alot of RV's are copper. I have never in a dozen years heard of of even one fatigue related failure on a copper line. We do secure them very well so I would think if one were to use them in a typical automotive application they'd probably work fine as long as they were well secured so that vibration couldn't cause fatique failures. Also when we go from frame to body or to a tank or any kind of motor we must always use a flex connection (rubber hose) to avoid fatigue. Once all that is said and done it's probably easier too use something else in most regular automotive applications.

dawg
02-17-2009, 08:50 AM
you cant flare copper tubing ( itll split on ya)
copper tubing isnt used in gas lines or tranny lines due to cracking etc. due to vibrations and accidents.

RPH
02-17-2009, 08:55 AM
Flare copper all the time here. If you split it, you are not doing it right. We use copper to carry the current on the Induction Power supplies, up to 2 megawatt.

Delray
02-17-2009, 10:30 AM
Everything rusts out in a few years in Upper Michigan and I replace lines after only 7 or 8 years even on a well cared for car. I now use Cunifer line which I believe meets industry standards for brake, fuel and oil lines.

fomocoforrester
02-17-2009, 10:31 AM
The main reason that you see far more steel than copper brake,fuel and transmission lines, is one of economics.

On high volume production, generally speaking, the more significant part of the cost is in the material not labour content. Therefore you go with the cheapest material i.e. steel.

On low volume production, generally speaking, the more significant part of the cost is in the labour cost, not the materials. Therefore you go with the lowest labour cost i.e. copper.

Copper is subject to work hardening, as is steel to a lesser extent, and is not neccessarily a problem. What does become a serious problem is if the work hardening process is allowed to escalate to where fatigue failure takes place. However, this can be completely prevented by adeqate design of the supports and fixings.

As with any sytem design, success depends on adequate specification of dimmensions, materials and proccesses involved. For example on brake lines, they should always be made up with double flare fittings, never compression fittings, and the copper should contain the correct amount of nickel (cunife).

There is a myth, that you sometimes run across, that says you should not use copper on fuel systems. This came about as a result of problems encountered when using copper in marine fuel systems containing high sulphur marine diesel oil. In these days of very low sulphur fuels and oils the problem is not the same as it once was.

Copper has another advantage over steel in that it requires less protection against corrosion.

All materials are subject to damage from misplaced jacks and jack-stands, and flying stones and obviously should be run in protected areas such as inside frame rails,

jerk_chicken
02-17-2009, 10:36 AM
No problems with copper going into Al?

fomocoforrester
02-17-2009, 11:21 AM
jerk chicken -

There is no problem with copper going into alluminum if both are grounded to a common ground and are not in contact with an electrolite such as battery acid or salty water.

A similar situation exists in an alluminum boat with a bronze shaft and propeller. No problem as long as the shaft is grounded through bonding wires accross the coupling or through brushes.

A possible problem could occur if the liquid in the line was conductive and both sides of the joint were not grounded to the same potential. - Not likely to happen in an automotive situation.

malibu101
02-17-2009, 11:22 AM
I have heard of vibration causing work hardening of copper too.

Why are most compressors connected to the tank with copper? :confused:

That seems like maximum vibration for a copper line to endure.:headscrat

bigdav160
02-17-2009, 12:07 PM
I have two large compressors at work that break copper lines at least once a month.

gunguy
02-17-2009, 04:24 PM
If not properly annealed, copper will age crack and work harden. It's one thing to use copper as a temporary fix to get home, but for a permanent repair or installation, I'd use steel.

Just my opinion.

Jim

Bustawrench
02-17-2009, 04:32 PM
you cant flare copper tubing ( itll split on ya)
.



I flare copper tubing everyday. It is a common trade practice in plumbing and HVAC/R work.

Bustawrench
02-17-2009, 04:36 PM
I have two large compressors at work that break copper lines at least once a month.

Sounds like something is wrong with compressors.

I've serviced thousands of compressors over the past twenty years and most all of them were piped in copper.

T56 Impala
02-17-2009, 04:43 PM
Copper cracks over time due to vibration. Ask old Harley/Indian riders.

SpiderGearsMan
02-17-2009, 05:47 PM
only use seamless steel tubing or equivilent
we used aluminum on s10 blazers and they rubbed through

swgray
02-17-2009, 07:22 PM
The right copper tubing would work fine. Same with brakes (http://www.merlinmotorsport.co.uk/advanced_search_result.php?keywords=copper+pipe) and fuel (http://www.victoriabritish.com/ICATALOG/SM/full.aspx?Page=83) line. More prevalent in UK and Europe. I have copper brake lines on my Midget.

It would be quicker and simpler for you to use steel lines, though. Less expensive even.

StingRay
02-17-2009, 08:00 PM
Or use stainless. It's readily avialable and reasonably priced. I ordered up a kit for my 92 GM pick up and got all of the brake lines for 200 bucks and they were a perfect fit. Worth every penny too. You can buy stainless tube stock coiled and bend your own too.

jjkrjh
02-17-2009, 08:48 PM
I work on industrial equipment(forklifts). Copper is and has been used for brake, fuel, and transmission lines from the manufacturers. The flares have always been a single flare, not a double flare. I would have concerns with fatigue and any external abrasions with running copper. Also copper brake lines were slightly thicker than comparible steel lines (ID). The brake systems were running boosters with no issues.

I wouldn't use copper for trans. lines. Your drivetrain is moving(unless you have solid mounts) and you are running lines to a stationary radiator. The lines are going to be held in some places with clamps that won't wear the lines and then have some hoops in the movement area to take up the vibration.

It is alot easier to bend up some steel lines. If you want them to look good polish with a rag and spray some clear on them.

Nealcrenshaw
02-17-2009, 10:59 PM
My main problem with the steel lines is that they're tougher to bend, not impossible just tougher,and was trying to breeze through it. But i guess in the long run the steel would be better. I saw both steel and Cu. for about the same price, $22 shipped on EBAY.

But i'll also check out those prebent lines junk was speaking of.

Pete D.
02-18-2009, 11:06 AM
I used a piece of copper pipe one time to fix my exhaust on one of my cars.:)

e-tek
02-18-2009, 08:37 PM
you cant flare copper tubing ( itll split on ya)


tsk-tsk-tsk dawg...:headscrat:(

JCByrd24
02-18-2009, 09:28 PM
Holy cow is this thread full of crap...copper is better for nearly any plumbing application than steel, period, where it can meet the specifications required. Copper is more resistant to work hardening than steel, more corrosion resistant than steel, and more workable than steel. As long as the wall thickness is good enough to meet pressure requirements and will not melt at the working temperatures it is better. The only area where it doesn't beat steel is cost, which is why it's used on cars. You get into copper alloys (copper with nickel added) add the same arguments apply. That's why the Germans and Brits have been using CuNi alloys on brake lines for a long time, the corrosion resistance outweighs the cost in terms of safety. Brakelines are one of the biggest safety features in a car and I'd bet money that given all the other "safety" crap we've seen mandated on cars we'll see better brakeline material required before too long.

That being said, back to the original post, there probably really isn't anything wrong with steel tranny lines to the cooler, as trans fluid is not corrosive. But if someone is compelled to use copper, there is nothing wrong with that. There is no magical electrolytic corrosion that will happen to the copper lines that won't happen to steel lines, and the pressure rating of the copper lines is bound to be higher than that of the radiator/cooler it's running to. The reason brakelines are double flared is to prevent cracking, as has been mentioned already, copper is usually single flared. Look it up people. Just because the auto industry does it doesn't make it "the best way", it usually means "the cheapest way".

speed bump
02-18-2009, 10:20 PM
You guys know that if you don't buy the cruddy flaring tools off the SO truck you won't split the copper flares like half of you guys seemingly do? With a rol-air flare tool I have spit one piece of ACR Cu and that piece was better than 20 years old and the rest I have never had a problem with. Thinking about it I have had more problems flaring steel than Copper lines.

As far as breaking the only times I have seen it happen in refrigeration are off of the compressor where it goes into a tight bend. If you don't think this out correctly (especially with big compressors) over time you will pinch the line and break it there. If this is unaviodable then you need to put in a vibration joint that will absorb that vibration.

The only thing I might be worried about is galvonic corrosion with Al but if its not in direct contact or carrying a fluid that is good for passing electrons (generally this is water) you should be fine.

Nealcrenshaw
02-18-2009, 11:03 PM
The trick to a good flare on steel is to use a drop of oil or brake fluid.

e-tek
02-18-2009, 11:18 PM
The trick to a good flare on steel is to use a drop of oil or brake fluid.

Good tip - done lots of flares, too dumb to have throught of this:headscrat

must8657
02-19-2009, 10:38 AM
I don't have any idea if copper can be used. but there can be many reasons why something is industry standard or oem. Most of the time the reason is it meets minimum requirements and cost the least. This can mean that copper may actually be better, but isn't used because it costs to much. case in point would be braided hoses and brake lines.
jason

Nealcrenshaw
02-19-2009, 11:14 AM
This can mean that copper may actually be better, but isn't used because it costs to much. case in point would be braided hoses and brake lines.

Good point jason