Size of Brake and Clutch Bottle Pipes and Hoses - plus Draper Flaring Tool

[rfs1957]

Anyone tempted by this tool would do better to steer clear.



When I used it ten years ago for 3/16" Cunifer on brake-pipes, the mandrel snapped almost immediately, which is probably why you see them listed as spare-parts everywhere.

Since then I've used this Franklin type of tool which is brilliant :



However, I thought I'd try the Draper again with 1/4" copper as I need to make a new set of hydraulic-feed pipes between the bottles and the master-cylinders to replace these rather tatty ones.



No matter what approach I take, using 3mm, 4mm, or 6mm of pipe beyond the clamp, it fails to make even the beginnings of a double flare, and even with the most modest clamping of the two halves it leaves horrible striations on the outside of the pipe.



Anyway, I'm now going to buy the same tool but this time in 1/4" .......



Which got me thinking - should the copper pipes be 1/4" or actually 5/16" ?

The spikes on the bottom of the bottles are very obviously 5/16", so why would they be associated with 1/4" piping ?



Another case for tapered hoses ? or just more opportunity for leaks ?

[Allrand]

Yes it's a problem trying to match the 1/4" to 5/16", it requires to much force to get the 1/4" pipe onto the 5/16" spigot, which invariably cracks the spigot or the bottle, particularly current reproductions. Anyone else have this problem?

[rfs1957]

Thanks Randall.

Looks like it would be actually very easy to sweat/soft-solder a 1"- long sleeve of 5/16" Cu pipe on the tails of all three 1/4" pipes, no ?

Good project for a wet afternoon .......

[mgcjag]

If you want to use 5/16 pipes on your brakes would proper brake fittings not be better than solder joints...just my thoughts...or use 1/4 and push it on the reservoirs...some obviously have problems doing this...most dont....Steve

[rfs1957]

My Sovy (?) brake-bottles are actually a very tight fit even with 5/16" pipe, there's no way I can force 1/4" on to them.

These are of course "feed" pipes, not "brake" pipes - zero pressure, zero risk of failure.

And 1" of soft solder in a 5/16" - 1/4" sleeve joint - in shear - is a million times stronger than either of the flexible hose junctions at either end.

[mgcjag]

Hi Rory....my point was to use 5/16 pipe with an appropriate fitting into the cylinder. ....Steve

[rfs1957]

Nice idea.

That would be a more elegant solution, but I can see two problems.

Firstly, the flare on a 5/16" pipe is incompatible with the 7/16 UNF thread of the master cylinders, as the flare OD is given as 0.418", and the root diameter of 7/16 UNF is only 0.3775".

It won't go in the hole.

Secondly, the tight bends required around the master-cylinders, tricky already in 1/4", might be impossible to obtain using 5/16" pipe with the kind of equipment we've generally got access to, certainly mine.

I think sleeving the 1/4 with a bit of 5/16 and soft-solder is the way to go, and what's more it will be invisible.

Watch this space.

[rfs1957]

Change of plan.

Decided to restore the existing ones, no idea if they follow the original pipe-runs - anyone got a picture ? - but they look vaguely credible.



5/16" Cu pipe does indeed fit a treat over the 1/4, and capillarity pulls soft-solder in convincingly.





So with an inch-long sleeve on the end of each one, all of a sudden the 5/16" hosing fits correctly.

[Allrand]

[MSM]

Beautifully done. Capillary action when soldering is one of life’s pleasures.