flexi brake hoses

[Richard Dryden]

Looking for a bit of advice, I'm building a siera based roadsters and was just wondering how to decide what length the flexi hoses need to be to go from the solid copper tube to the discs on the front and the drums on the back. Furthermore where have you all sourced them from.

Cheers in advance.

[K4KEV]

Voucht on here is your man to talk to re brake hoses

[voucht]

Thanks Kev

Hi Richard,

For book chassis, (Sierra, front discs brakes) front lines should be 450mm long overall. Set-up is:
- straight fixed male M10x1.00 fitting on calliper end
- straight fixed bulkhead male M10x1.00 fitting + M10x1.00 lock nut on chassis end

But for the rear, there are differences. For example, on my chassis, I welded the rear brake line brackets under RS7/RS7a, which makes more sense to me than the book design. So my rear lines are 450mm long overall as well. If your brackets are placed like in the book, the brake lines would need to be a bit longer I think, and you'll have to measure them: using a 1-strand copper electric cable to mock up the flexi route is a very good way to take the measurement. Overall length of the flexi should be measured from the seat inside the fitting on the copper pipe to the seat inside the rear drum cylinder. Plan for wheel vertical movement as well

The rear brake line set up will also depend on if you put the bit of copper pipe between the drum cylinder and a bracket welded on the rear upright as explained in the book, of if you want to go straightly into the drum cylinder with a 45° male fitting. See details on this page: https://sites.google.com/site/hydrau...s/special-case

There is a third option, which depends on the origin of your rear uprights. If they are from Talonmotorsport, like mine, you can use a fixed male fitting to go directly into the drum cylinder (see this album on my flick-r pictures https://www.flickr.com/photos/994983...57646841607980)

So :
Copper bit like in the book :
- straight fixed male M10x1.00 fitting on drum end
- straight fixed bulkhead male M10x1.00 fitting + M10x1.00 lock nut on chassis end

45° direct-to-drum-cylinder :
- 45° swivel male M10x1.00 fitting on drum end
- straight fixed bulkhead male M10x1.00 fitting + M10x1.00 lock nut on chassis end

"Talon style" rear uprights :
- straight fixed male M10x1.00 fitting on drum end
- straight fixed bulkhead male M10x1.00 fitting + M10x1.00 lock nut on chassis end

Hope this will help

Good luck.

[NeilW]

I am pleased this post was made, I was just about to post the same thing.
Great info, especially the tip with the wire. I am running disks at the rear so I am sure that method will help.
Any idea of recommended suppliers?

[voucht]

Originally Posted by NeilW

Any idea of recommended suppliers?

I'm no longer working for the company manufacturing the 100% stainless steel brake lines (we supplied a lot of builder on here), but I'm pretty sure they will be OK to keep on supplying forum members. Please send me your specs by PM (fittings at each end, overall length, colour*), and I'll get you a quotation.

* the stainless steel braided Teflon hose comes with a PVC cover available in 26 colours:
Anthracite grey
Silver grey
Blue
Denim Blue
White
Neon Blue
Turquoise Blue
Yamaha Blue
Carbon Look
Clear* (not coloured)
Gold
Clear* Gold
Yellow
Clear* yellow
Military Green
Mauve
Black
Clear* black
Orange
Clear* orange
Red
Clear* Red
Pink
Green
Purple
Clear* green
Dull Black
* Clear = see through
If you want no colour, chose the “Clear (not coloured)” cover, it is non-coloured see-through PVC cover, so it keeps the natural look of the stainless steel braid.


Thanks!

[K4KEV]

Originally Posted by NeilW

I am pleased this post was made, I was just about to post the same thing.
Great info, especially the tip with the wire. I am running disks at the rear so I am sure that method will help.
Any idea of recommended suppliers?

I'd have sent you the same place mate, his/was brake lines are well tidy check mine on my build thread

[flyerncle]

Sylvain,this has been a question on my mind everytime I see full flexible stainless pipes used,what difference if any is there to the overall brake pressure,as against using metal pipe and flexy's.

And this is not meant to put anybody off using them as the quality is second to none as others will say too.

[voucht]

Hi Paul,

That is a legitimate question

Actually, technically, when it comes to overall brake pressure, for us, there is no real upside of using full SS (stainless steel braided Teflon hose) lines instead of copper pipes on the non-flexible lines of the brake circuit.

However, on the paper, SS braided hose has a higher service pressure than copper pipe (that is the reason why it is preferred in racing cars for the whole braking circuit, as very high braking pressure can be reached):
- service pressure of 3/16'' copper pipe is 250 bars
- service pressure of dash-3 SS braided Teflon hose is 320 bars.

But I doubt these kind of braking pressures are reached in our cars, so this is not a valid argument when it comes to our Roadsters. Therefore, we can consider that there is no difference in that matter between the 2 kinds of hose, and also that there will be no deformation under pressure on both of them (which is different when it comes to flexi only: SS braided ones will always be better and offer better braking consistency than OEM "rubber" ones, because they don't swell, or get dilated, under heavy pressures, as OEM flexi might do).

But there are other things to consider, and there, SS brake lines have some upsides that might be worth considering:
- durability. They won't rust. I personally saw damages of the corrosion on copper fuel pipes in my Renault Rodeo (which is basically a Renault 4), and it is blood scary! But I'm sure you've seen worth in your career
- stainless steel braid provides protection against both wear (friction) and shocks (such as projections of stones)
- no tools required to bend the pipe. Easy to assemble as it is flexible.
- no tools required to make the seats on the pipe: proper fittings are crimped on the flexi lines.
- fittings of the brake lines the company I used to work for supplies are in stainless steel, and not in plated steel, so they are also more durable than the cheap fittings usually used with copper pipes.
- very neat finish on the car: SS lines looks very technical and professional.

The downsides, if you compare to copper pipes are:
- of course, the price. But it is less a hassle to install also,
- you can't achieve very tight curve radius with the SS braided hose (not as tight as with copper pipes): 38mm mini for dash-3 SS braided Teflon hose, 10mm for 3/16'' copper pipe,
- with copper pipes, you “fabricate” the lines directly on the car, while installing them. With a full SS line circuit, you need to plan for each line which will compose the circuit before ordering (length and both fittings). It is not hard to do, and I provide help for that (schematics, etc.), but it has to be considered.

So, I think it is like most of the other elements of the car: it is just a question of choice, what to favour between technicality, practicality, durability, cost, look, etc. but it is good to know the perks and the downsides, so thank you for your question, and I hope I answered it

[Richard Dryden]

Hello Sylvain, thank you very much for all the information will have to work out what I need exactly. I will get back to you as soon as I do some measuring etc.I almost just private messaged you but I thought it may be a useful question for other builders too.

Cheers Richard

[flyerncle]

Valid contribution (not argument ) for and against for both,it just gave me food for thought and other peoples thoughts on the why and wherefore for both.

Just checked my pipe stock and they quote theoretical burst of 965 bar and working pressure of 214 bar so safe enough for our use and that is 3/16 pipe.

Merci Mon ami.