Brake Pipe Unions

[ArthurH 7]

We are just about to make a new set of brake pipes for the 205GTI.  I have a flare tool; I'll buy some tubing and a bag of unions.  The championship rules constrain us to use the standard calipers and rear cylinders.  To save me checking each one individually, are all the OEM brake threads 'standerdised' across the car (including the master cylinder)?  E.g., M8 everywhere?

Any good tips before I start?

[welshpug 1,666]

Mostly M10x1.0, a 1.9 will have a pair of 12x1.0 into one side of the brake pressure limters

[petert 597]

Can you manage a double flare though? I single flare would surely be illegal? I've approached this a bit differently and changed to 3AN hose where appropriate/possible. Here are some Speedflow part numbers you might find useful:

 

T200-C03 200 series -3 hose Teflon® Stainless Steel Braided Hose

260-03 life saver

380-03 1/8 NPT adaptor

344-03 dual seat

201-03 straight hose ends

https://www.speedflowdirect.com.au/

You probably have a similar supplier in the UK. And if you do it stainless fittings, hose and lines, you'll have no issues with corrosion.

Edited Thursday at 06:27 AM by petert

[ArthurH 7]

Thanks Peter, just for the avoidance of doubt :-), you are using the braided hose throughout the braking system, i.e., no rigid pipe at all?  If so, the brake pedal feel is not more spongy? 

[petert 597]

No, I use hard lines on the straight parts, but around the difficult to bend parts, I'm using the stainless teflon hose. Even just changing to stainless teflon hose, replacing rubber hoses will improve the pedal feel. I did that on my road 306. I have a friend who did his entire 206 GTi180 in stainless teflon hose and the pedal feel is magnificent.

[ArthurH 7]

I think we may follow your lead and go for a hybrid solution. Picking up from Mei, I think we will have M10x1 throughout - except for the two sides of the Willwood bias valve (1/8NPT?)

[ArthurH 7]

Now I am looking at this in more detail, I am uncertain what sort of 'flare' we need.  Just using these two listings from the same seller as a convenient example, one says "convex" flare, and the other (a different price)  "straight", but I am struggling to see the difference.

 

https://www.ebay.co.uk/itm/146306095109

 

https://www.ebay.co.uk/itm/146103209481

[welshpug 1,666]

Those two fittings look the same to me

 

The typical flare on european cars is a DIN single flare, mushroom shaped, rather than the american SAE bubble flare.

 

You wouldn't buy those fittings to connect to the hard lines anyway, the car side of flexible lines are female fittings with a groove for a clip, the rear lines from body to axle is female both ends other than the left side on a 1.6 that had  a male fitting screwing directly onto a Tee secured to the body on a stud.

 

[ArthurH 7]

Thanks Mei, I was considering following Peter's suggestion above of dispensing with the hard lines altogether, but I'm still undecided.  Can I infer from what you say that they would be suitable to join braided PTFE hose to the calipers, master cylinder and slave cylinders?

[Bremar 2]

Not that I know that much and I don’t want to contradict Welshpug as he has been very helpful to me but I think double flared brake pipes are the European standard rather than single flares. Single flared are not safe enough for brake systems. Flaring steel brake pipes is too difficult to DIY in steel so next best IMHO is copper nickel pipes which are harder than copper (which I cant imagine are acceptable in racing but maybe they are ) but still easily bendable. Just buy a flaring tool and practice until you get the double flare right. There are plenty of YouTube vids on making up brake pipes with double flares.

Bremar  
 

Edited 38 minutes ago by Bremar

[Bremar 2]

From left to right. Single flare,  double flare and bubble glare.