6 replies to this topic

[ukcooper]

Brake pipe questions
1993 rover sprite with servo

• Is it cooper or Cupro nickel brake pipe I need?
• Unf or metric fittings
• 3/16 pipe or 4.75mm
• Sae or din or sae/din
• Flaring tool, bench or hand held ( links below )

http://www.ebay.co.u...984.m1423.l2649

http://www.ebay.co.u...984.m1423.l2649
sorry it’s short and sweet but having problems using the pc
Cheers

Edited by ukcooper, 09 April 2013 - 03:46 PM.

[Gremlin]

Hand held, you can then flare it in postion, dont want to bending once to get the right length, then again to get it out, then bending AGAIN to put it back in, the pipe will go so hard and difficult to bend

[lrostoke]

I've used this kit on 4 different cars

http://www.halfords....tegoryId_255216

Edited by lrostoke, 09 April 2013 - 04:30 PM.

[Brigbeale]

OR
http://www.machinema...&TC=SRC-flaring

I bought one of these a while ago. http://www.machinema...&TC=SRC-flaring
I already had a mini tube cutter from B&Q. They work well but just remember to put the fitting on the pipe BEFORE you flare the end.

Edited by Brigbeale, 09 April 2013 - 04:46 PM.

[tiger99]

Use cupro-nickel only (aka Cunifer or Kunifer). Although some here refuse to believe in metal fatigue, it is established fact that copper will suffer fatigue fracture after an inadequate number of heavy brake applications. Also, there is no proper spec for copper brake pipe, in fact it is not recognised by any standards body anywhere in the world. The stuff that is sold with a BS spec is not brake pipe at all, as teh spec is for copper pipe for general use, not high pressure hydraulic systems. Sadly, a large fraudulent industry exists in the UK, supplying that lethal junk. Note that copper is illegal in the US (where regulations about modifying cars are rather lax), and in Australia and most of Europe.

The stuff that you want will be Alloy C70600 and will be approved to some or all of ASTM B466, SAE J527, ASTM A254, SMMT C5B (relevant to the UK) and ISO 4038.

[Dan]

Mostly UNF but there are some M10 and M12 at the bulkhead regulator.

[tiger99]

Dan is right, and I would only add that you should be very careful to avoid confusing M10 and 3/8" UNF. People on various cars have made that mistake and had brake failure, usually soon after. It is very unfortunate that two incompatible sizes which are so close are allowed to exist.

As always, if it is correct, it will screw in all the way until the tube flare bottoms out with only finger pressure, but will not be loose and wobbly, if the threads are correctly matched. If it needs lots of force or is loose, it is wrong. That goes for almost all threaded fasteners everywhere, not just brake pipes, with the exception of taper threads used on oil pressure switches etc.

There is a further slightly less dangerous possibility of confusion between some BSW and UNC threads, but you will not find either of these on a Mini brake system. But don't use BSW "Whitworth" bolts on the transmission case! You may strip the alloy threads, as the thread angle is not the same, even though the pitch is, so the load and torque capacity is reduced. On the other hand, the tripod fitting on the bottom of cameras and camcorders is 1/4" and used to be BSW but nowadays is UNC, and in a lightly loaded application with loose tolerances, mixing them is perfectly acceptable.

Nuts, bolts and threads are stuff that we all need to be aware of. There are some metric bolts, with matching nuts of course, on later Minis, and then there is the nasty little problem with the threads in the suspension cones. But let us not digress into the thread on the flywheel centre bolt......