Hi All

Was surprised to see a roll of 3.5mm copper pipe on ebay the other day. Which Citroens can this be used for? As far as I know normal Citroen pipe is steel either plastic coated or black painted. Pliaedes supply cupro/nickel pipe which is supposed to be less of a rust risk. Anyone able to give me a quick summary of the different metal pipe options and sizes needed for an XM. Also what type and size of flaring tools are needed beyond the 3.5mm one I already have.
Similarly what about the sizes and materials of the rubber hydraulic hoses on an XM as these must resist LHM which does not seem to mix with normal rubber hoses.

John

I saw that and wouldn't buy it as it was totally copper NOT cupro/nickel. Most imperial sized brake
lines can use the 3.5mm copper pipe but it seems specific Citroen for the cupro. Pleiades and even
GSF have been selling this for years and I wouldn't detour into using something else that to me is
untested.

The 3.5mm pipe is available as a 50m roll IIRc costing around £70 so the offer on ebay wasn't that
great a deal per metre anyway!

The only other size where there are available pipe/ends/flaring tool and seals is 4.5mm and is only
used in limited areas like the FDV to accumulator and rear anti sink. Then you're talking about
6.5mm which IIRC is only a single pipe on the car anyway.

Andrew

Andrew, George

Thanks for that. Part of the interest was from having used 8mm and 10mm ductile and easily bendable copper tube very successfully over the years for domestic heating. That application is much lower pressure but very easy to joint and work with so I wondered if it was just the higher cost of copper that stopped it being used on Citroen cars.

John

Pure soft copper pipe has the advantage of being very easy to manipulate and flare but I would never entertain it's use for brake lines because of its tenedency to work harden. Once hardened, any vibration of the pipe can eventually lead to the metal cracking. This failure is much less likely (though not impossible) on properly supported steel or cupro-nickel pipe. If I remember correctly there have been reported incidents of the steel HP pump to pressure regulator pipe cracking when the original pipe supports have been left off after maintenance.

Ken

PS Don't know for sure what Citroen uses for LHM but two well known rubbers with good mineral oil resistance would be 'Viton' (fluoroelastomer) and 'Nitrile' (Acrylonitrile butadiene), although there may be others.