[heat] shields up!

So um why do my brakes feels squishy all of a sudden? Like… Horse and buggy-like brake performance that requires Flintstones effort..
Ever get that feeling?

Quickly check out your brake fluid and notice the levels in the master and secondary cylinders. Low!

So why? Visually inspected the brakes: good amount left. No brake fluid leaks. See something missing here?

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Huh! Wasn’t there suppose to be a heat shield here? Yes! Car came without the heat shields, and if Datsun designed them, it needs them, and now I know why. Brake fluid can break down at high heat (remember, we’re in a 280z haha).

Now I think a few things are happening here:
1) brake cylinder caps aren’t tight enough allowing the brake fluid to absorb moisture from the atmosphere, severely degrading it’s boiling temp.
2) engine bay is hot enough to heat up that brake fluid enough to evap.

Boiling temp of DOT3 brake fluid specs out to be around 400F (dry), and 284F (wet, meaning when it’s absorbed enough moisture). Huh, so 284F isn’t too far from 212F (boiling temp of water, for reference), and I know my 280z engine gets hotter than that.

So I knew I at least needed a heat shield, and order one from eBay ($35 + $10 ship). Ugh.. Wrong one. Do you know how hard it is to find a 280z brake cylinder heat shield?! So I picture match it with a ’79 280zx version.. And I thought they were the same…oops, nope..

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3 Replies to “[heat] shields up!”

  1. You know, I’m having the exact same problem. And I live in Tabasco, so it’s like really really hot all the time (the coldest we’ve been is 14°C, just one day, like in january, and that was it).

    So, what did you do to correct this?

    1. Hey MrCherno! I actually just went ahead and got the appropriate heat shield for the car – used of course! After that, I haven’t seen the evaporation that I was experiencing without it! good luck!

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