Master Brake Cylinder - Preventive Maintenance?

[TargaFlorio]

Hi Guys,

I'm replacing my brake calipers, rotors and pads on my '68. I'm also flushing out the system and filling it up with ATE blue fluid.
There was nothing wrong per se with the brakes, just regular maintenance.

As I understand it, the Master Brake Cylinder can start to leak over time which affects brake performance. There's nothing wrong with my cylinder as far as I can see. It's bone dry and does the job. Would you still replace it (part of the "while you're at it" philosophy)? Or would you just leave it be?

The car already has stainless steel brake lines. In general my car is unrestored so I replace mechanical items that have broken or need replacing (like new shocks etc.).

Cost isn't really a factor as I already have a NOS brake cylinder sitting on the shelf, I'm just curious about replacing things that aren't broken.

Do you consider the master cylinder to be a part that regularly wears out (like pads and rotors)? Do you wait until it starts to leak or breaks or is the master cylinder part of your preventive maintenance?

Would appreciate your thoughts.

Thanks.

Ciao,
n.

[Kris Clewell]

I wouldnt touch it if its not leaking. Its typically not considered a "wear" item on a car.

edit: but if you are that far into replacing all the brake components, and you WANTED to do it, now would be the time.

[Davz912/911]

Regular flushes and your good to go...

[TargaFlorio]

Thanks guys. I will let sleeping dogs lie.


Ciao,
n.

[304065]

Nicolas,

While you are under, take a look at the stainless brake lines. I have bought two cars that had these, both were SAE threads that required adapters to the European M10x1.0 pitch ISO brake lines-- and they didn't have DOT certification. The DOT-certified lines for street use have plastic boots on the end that limit the amount that the line can move-- sort of a vibration damper to prevent the comparatively stiffer stainless braid from fracturing.

Anyway, I have had great success replacing those lines with new ATE rubber hoses. I think the thing about stainless giving a harder pedal is a myth-- if one's rubber lines are truly bulging under hydraulic pressure it's time to replace them, NOW!

Good luck and have fun!

[TargaFlorio]

Hi John,

I didn't do the stainless steel lines on my car, they were already on there when I got the car. They don't have the thread adapters (they are metric) that you mentioned.
I have heard the same thing about harder pedal pressure being a myth with stainless steel lines (the inside of the stainless lines contains rubber anyway). I was under the impression that the stainless lines give better protection from the elements?

Ciao,
n.

[Flieger]

The stainless lines should be teflon on the inside, which is stiffer than rubber. The braid started out for race cars as protection from road/track debris. But the stainless braid is much stiffer than rubber as well so it reduces even more the expansion of the thin layer of teflon inside.