[jjb]

Apparently, after being torqued down for 40 + years, some of the tube nuts on the brake lines have become flared, or "bell-mouthed" themselves. I found this when I tried to put some unions on these and they wouldn't go in because of this effect.
The two nuts on the output ports of the MC suffer from this, and although they will go in the ports, there is resistance which would seem to keep the full force of the nut's torque being applied to the flare to seal it.

Take a look at the nut on the left compared to a new nut on the right. see the unthreaded leader at the tip that applies the pressure to the backside of the flare ? That is where it is splayed out in a bell shape. It doesn't look like much in the picture, but it is enough to prevent it from working in some fittings.

This seems really weird, even for an Alfa. It implies that many of the fittings on the car need replacing. Anyone else seen this ?

Cheers,
Jeff

 

[PAUGNUT1275]

Flared brake nuts??

Hi
Good photo to demonstrate the issue. We run into this fairly often with older Alfas. As long as the nut hasn't developed a crack, simply use a small file to take the "extra" material off the edge of the nut. Then it will fit down the hole of the M/C or fitting, without dragging on the way in. If the steel lines are bad, we make new ones with Kunifer tubing. You will need a really good flaring tool however. We use a fancy Swedish model. Fed Hill in Mass. sells the Kunifer kits and the tooling.
KG
Alfas Unlimited

 

[jcarr]

Looks very familiar and I assume very common. Almost every flare nut of this type on my '69 spider was like this and was the cause of many annoying leaks when I was restoring the braking system. Either file off the extra metal so the nut seats properly or even better, replace them and the brake line.

Good luck!

Jeff

 

[jjb]

Thanks guys for the replies. Well, its good to know that at least my car isn't unique with this. Looks like I may be in for replacing some lines and fittings, or at least some precision filing/grinding.

Maybe this will turn out to solve some mysterious leak issue I seem to have.

Cheers,

Jeff

 

[GregSef]

I also saw this on the bubble fitting nuts. I have also filed the ends to fit into the female ends. I replaced some fittings when I could. I can attest to the quality of everything that Fedhill sells for brake and clutch lines.

I think the fittings deform from people cranking on them in the mistaken belief that tighter is better.

I bought the swage style flare tool from Pegasus racing and am very happy with it. It does SAE and buble flares equallyy well in any material. Not cheap though. It is manufactured by Sykes-Pickavant in the UK. Here is a link to one on eBay.

Sykes Pickavant Brake Pipe Flaring Tool 3/16" 4.75mm | eBay

Greg

 

[jjb]

Greg,

That flaring tool looks nice. If I have to start replacing lines, I may be in the market for one. After my experience with the KD flaring tool, which turned out to be worthless at doing 3/16" bubble flares, I won't make the mistake again of getting a bargain tool.

Cheers,
Jeff

 

[mhunger]

this is *exactly* what I just found on my 69! I just filed the bell shape down and got it to go into the new MC. thanks for the observation.