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Old 10-24-2009, 11:44 PM   #99
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Location: Wabash, IN USA
Posts: 104
We had our suspected copper brake line checked at Onan/Cummins in Elkhart, IN this past week. The technician initially thought the line was copper but my husband did not. Chuck detected a slightly different hue/shade when the line was cleaned and polished. It was decided to remove the line to get a better look at it and the fittings on both ends. The technician removed the line and contacted the people who manufacture the cunifer line at FedHill to find out how to determine the composition of the material.

They told him their product is 90% copper and 10% other materials mostly nickel. They walked him through the process to determine the composition and it was determined that our line is cunifer and not copper. The real problem our technician saw was with the compression fitting on the end going to the flexible hose that goes to the caliper. He had never seen that kind of fitting used on brake lines and said it could be a recipe for failure. Also, the fastening of the line needed to be more secure in places. We have 38,000+ miles on our 75636 Apex coach and it had one place where one of the clamps was slightly loose and had started to polish the line a little due to vibration. There were no sharp bends or kinks in our line and it was not rubbing against any parts.

Here is how the manufacturer instructed the technician determine the compositon of the line. First of all, he was instructed to polish the line the best he could. He then was told that if the line were cunifer the finish would be closer in color to 12K gold than to copper color like a new penny. When polished, ours was definitely much lighter in color than a new penny and close to the gold color. The final test was using a magnet. The cunifer contains a very small amount of iron. They had him use a very strong small magnet not attached to anything and had him pass the metal line next to or over the magnet. Our technician had a small round roller ball magnet from a child's toy in his tool box and he placed it on a plastic cap from a paint can to get it away from any other metal. He then placed the suspect line close to it but not touching it and the magnetic ball rolled toward the line. According to the manufacturer of the cunifer line there is not enough iron in the line for the magnet to latch onto it as a magnet does steel but enough for it to detect it and what they call "kiss" it. This might explain why the magnet tests done on other lines may or may not have determined what the line really was. The magnet test he did would have been very difficult to do under the coach. Having removed the line made it much simpler to perform.

Having confirmed our line was cunifer and that the less than desirable compression fitting needed to be replaced, a new part was obtained and installed. Better supports were installed for the line. Brake fluid was changed, lines bled, etc.

Now our experience does not mean that there are not some copper lines out there. It did confirm that on ours the less than desirable compression connection and lack of proper support of the line needed addressed.

I hope the above makes sense and that our experience helps you in some way. I have now learned more than I really ever wanted to know about brakes. Oh, the joys of being an Alpine wife.

2006 Alpine FDQS Apex
"The Butterfly Express II"
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Old 10-25-2009, 09:43 AM   #100
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Location: Auburn, CA, Havasu, AZ & Mulege, BCS
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I think all the "possibly copper" lines are Cunifer, and outside of installation issues, the material is OK. I'm not big on the compression fitting myself, but if that is all the issue I had, I'd leave replacement of this line till I was a lot further down my list of gotta-fixes.

Baja-tested '08 2-slide 36'
Alpine: The Ultimate DIY'er Project
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Old 10-31-2009, 12:30 PM   #101
Join Date: Jan 2009
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Assuming for the sake of discussion that all of the "copper" lines discovered were in fact "cunifer"---what are the pros & cons of cunifer to consider in any decision to to replace it or simply leave it persist in position? There must have been other factors besides cost that lead WRV to change from steel to cunifer. Any explanation would be appreciated.
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Old 10-31-2009, 08:24 PM   #102
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I think WRV used cunifer because it is easy. Bends easy, supposedly difficult to kink (tho they disproved that sales pitch on my coach), easy to fit up ends. In short, if you were to look for a DIY brake line, cunifer would be a good choice.

Only down sides IMO are compression fitting on one end which isn't the best (rather see a flare), and flex imparted on a too-long unsupported end which can "work" the tube till it fatigues. That last is a biggie, though easily fixed.

Baja-tested '08 2-slide 36'
Alpine: The Ultimate DIY'er Project
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