6 replies to this topic

[Tremelune]

I have a '92 JDM-spec Mini with a McGee subframe in it (built from Allspeed towers). The brake pipe from the rear of the car to the front is just a touch too short to reach the master. Could I get away with a short, flexible "extension" or is it worth it to replace the whole pipe with something slightly longer?

 

I've never bent/run my own hard brake lines before. Long-term plans include all new bits to fit 10" wheels (down from the current 12" wheels) as well as adjustable bias control, but I was really hoping for a cheap/simple solution until I can get this car street legal.

 

I'm confused by pipe fittings (particularly because we Yanks have our own system). Is there a way I can find out the "specs" of the lines and fittings to ensure a leak-free fit from whatever I purchase? GHT, NST, BSPT, NPSI, FIP, MIP, taper, non-taper??

 

Is bending and flaring lines as simple as this page suggests...?

 

https://nasaspeed.ne...wn-brake-lines/

[Tremelune]

Tangential question: Is there a way to add redundancy to the system in case of failure? Modern cars have two circuits that go to the RF/LR and LF/RR wheels, respectively, but I only see one line going from the front to the rear on this Mini.

[nicklouse]

your car should already have a front rear split system.

 

photos would help.

 

fittings tend to be 3/8unf flare depends on what it is attaching to and with what. be aware not all fittings are 3/8unf as there can be an odd metric one on the Master and/or the pressure valve.

[Ethel]

Making your own lines makes sense, especially if the car's not standard, or  your parts need ordering & delivering from afar.

 

Depending on how short that touch is,  a banjo fitting might do the job. There are cheap joiners, but you'd need to make some flares to insert one, or acquire another line.

[Chris1275gt]

Flaring a brake pipe is really easy 2 or 3 practice goes and your ready to make the extension as Nick says make sure you check you've got the right nuts for the mastercylinder and don't forget to put the nuts on before you flare the pipe. It's really inexpensive as well.

[Spider]

I'm not keen on attaching flexible hoses to rigid lines without support at the connection between them.

 

All the piping in the Mini is standard 3/16" Brake Bundy Tubing. I'd suggest avoiding Copper Tube here.

 

Most of the fittings are as Nick said 3/8" UNF however those on the Tandem Master Cylinders and the bulkhead mounted Regulator are M10 x 1.0. Beware - the 3/8" fittings will screw in to these Metric threads, but don't have enough thread engagement for safety. Try a good wheel nut on the original tubenut, if it goes on, it's 3/8" UNF if it doesn't, then it's highly likely it's M10 x 1.0.

 

Get decent tools, especially for doing the flairs. They type that have the 2 thin bars with multiholes and a screw press are usually rubbish (I haven't seen a good one yet).

If you are only likely to do say 1 or 2 cars, this is a good tool  https://www.carbuild...e-flaring-tool  though, look around, as similar ones pop up on ebay and the like.

 

I'd also suggest getting a tube straightener as when you buy the pipe, it's in a coil. You can straighten it by hand OK, but it never comes out nice. Using a straightener will get them dead straight. This is a cheap one that's ~ OK ~ https://www.carbuild...raightener-tool   though, if you are a little handy, you can make one for a few dollars.

 

A Tube Bender will also let you make nice bends.

 

I rather enjoy doing this type of work. Take your time with it, making a template sometimes is a good idea in welding wire. When I do them, I start at the end with the tightest bend or the end that needs the most work or is critical in some way, fit the tubenut, do the flare do all the bends, cut to final length and finish the other end.

 

There's 2 types of Pipe Flares n the Mini. The most common end is what is often called a 'ball flare' and these are what's done on all the tube nuts. There's also 4 Invert Flairs, which are made with the same tool (usually!), first making a Ball Flair, then a second operation to invert the Ball. These are for the Female Tubenuts that connect to the Flex Hoses for the swing arms.

 

[Tremelune]

This is very helpful, cheers!