Brake fluid filler cap

[tchalikias]

Just a quick question, how tight should the brake fluid filler cap be?

I was checking around the engine and found that the filler cap wasn't perfectly tight. And the way its designed apparently, you can't overtighten it - it loosens up again after a few turns.

Should I tighten it up as far as it goes? Or is it better not to tighten it in case of air buildup in the reservoir etc?

 

[ben_r1]

Not really something you should think about too much mate, just as tight as you would a milk carton top.

No need to worry about air build up as it'll be vented anyway to relieve vacuum as the resevoir should need to empty to replace lost/low fluid in the system.

Just nip it up with your hand and it'll be fine.

 

[tchalikias]

Well I tightened it as far as it would go.

I also noticed that when fully tightened, one side of the cap sights slightly lower than the other side, i.e. its impossible to tighten it evenly all around. Which kind of makes sense, since as the fluid level drops, air needs to come in the reservoir (and get out in case of excess pressure)

 

[ben_r1]

No sounds to me like you're putting it on wonky mate, possibly cross threading it as you graunch it up. Luckily because its just a plastic cap it'll just deform instead of damaging the thread.

 

[tchalikias]

Well I tried putting it on a couple of times.. When tightening it up, after a certain point you can feel its not on completely straight (using a finger to feel the thread behind the cap).

Perhaps I'm overtightening it?