Topic: CB400F Brake fluid capacity

[Alaxy Galaxy]

Gotta question:

how much brake fluid is needed to fill a freshly overhauled front brake system on a CB400F?

Thanks.

[slikwilli420]

Enough to get all the bubbles out and get nice lever feel. It may take a half pint, or a quart. It all depends on your brake system. I hope you are not trying to squeeze by on an opened container, thinking it will be enough. Brake fluid is cheap and should come from a sealed container.

[Alaxy Galaxy]

No, not at all. I've just recently rebuilt my braking system and want to purchase enough fluid to fill and bleed it, but not too much because any unused brake fluid is unusable brake fluid.

My options are basically 1L and 4L.

[slikwilli420]

No, not at all. I've just recently rebuilt my braking system and want to purchase enough fluid to fill and bleed it, but not too much because any unused brake fluid is unusable brake fluid.

My options are basically 1L and 4L.

Now I see. Sorry to be snappy, shouldn't have assumed. 1 liter should be more than plenty. Some find it easier to bleed them off the bike then fit them back on.

[Alaxy Galaxy]

Now I see. Sorry to be snappy, shouldn't have assumed. 1 liter should be more than plenty. Some find it easier to bleed them off the bike then fit them back on.

Really? I can't see that happening with the headlight and all the other cables in place. Anyway, bleeding one circuit shouldn't be too bad.

Thanks for the info. And no worries about your assumption - important safety advice is always good.

[Flyin900]

CTC does sell 500ml sizes usually in specialty types, yet more expensive.

Never had any issues with open containers myself. Just how much moisture is it going to absorb in a open sealed bottle? I have a small gauge that can read moisture content in the fluid; it has never shown any moisture content in an open container.

[dave500]

500ml is common I would've thought?

[slikwilli420]

CTC does sell 500ml sizes usually in specialty types, yet more expensive.

Never had any issues with open containers myself. Just how much moisture is it going to absorb in a open sealed bottle? I have a small gauge that can read moisture content in the fluid; it has never shown any moisture content in an open container.

Relative humidity is a major factor and with you in Canada, I would imagine the humidity is far less on the average day than in Florida. I agree with you that if you are careful and close the bottle tightly and keep from major temp swings, it should be fine. I opened my fluid for my race bike and once done pouring into the master, cap went right back on. Once I was done I screwed the cap on tightly and ran a few rounds of electrical tape all the way around the cap/neck, so it should be as sealed as it was with the foil cap on. I will use that fluid again this year with no worries.

The bigger issue is once its out of the bottle and in your system. There are extreme temperature swings in the brake system which will cause the formation of condensation in the system.

[dave500]

so many #$%*ty cars on the road thatve never had a brake fluid flush?its pretty resilient to some moisture,dont over think it.

[ekpent]

 I don't bother but a friend of mine just pokes a small hole through the foil cover that is on the top of the bottle and does not remove it. Says it lets even less moisture contaminate then totally removing it.