Anyone replaced all the brake lines?

[Don C]

IDK, I've got cars with 25yr old brake fluid in them still working fine. Its a sealed system. Where's all the water coming from?

The vent hole in the cap is the culprit. Every time the atmospheric pressure or temperature changes the cap 'breathes'. Because regular brake fluid is hygroscopic it pulls the moisture out of the air.

 

[giantpune]

The vent hole in the cap is the culprit. Every time the atmospheric pressure or temperature changes the cap 'breathes'. Because regular brake fluid is hygroscopic it pulls the moisture out of the air.

Does the rubber membrane have a vent hole?

 

[Don C]

Good point, but any imperfection or dirt on the rim of the master cylinder will allow air (and moisture) in. Improperly storing bottles or cans of brake (loose or missing caps) will let the brake fluid suck in moisture. Just pouring brake fluid into the master cylinder will add a little moisture, as will just checking the brake fluid. For those that live in the southwest (unless during a monsoon in Arizona) this will be a miniscule amount, for those that live in high humidity areas the absorbed moisture will be higher.

 

[Sheriff41]

I replaced all of mine with the nickel/copper and used the Hand held brake flaring tool ( Ebay £19.00 ) and a hand held bending tool to create smooth curves.
Can someone advise me, What size is the brake pipe, are there two sizes, because I'm sure my PV has two different size threads, or has this been done deliberately by the manufacturers so that you do not put the wrong pipe in the wrong PV port?

I think all the brake pipe is 3/16" but the tube nuts vary.

 

[Bobby]

It’s best to replace everything. Suppliers carry the oem style steel pre-formed lines or you can get stainless pre-formed lines…or you can buy a coil of copper-nickel brake line and custom fit them yourself. You’ll need a bending tool and flaring tool. You can remove the intact lines and lay them out on your garage floor and replicate each bend side by side. Also, there are several good videos on YouTube that will show you how to make inverted flairs.