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Brake fluid
David Jenkins - 3/4/02 at 09:02 AM

Can anyone give me a rough estimate for the amount of brake fluid required to fill and bleed a Locost's brake system?

The reason for asking is that I'm planning to use silicone brake fluid rather than the usual glycol-based stuff, and it's bl**dy expensive! The bottles come in 250ml, 500ml or 1 litre, so any estimates should be based on those quantities...

Why use silicone? Mainly because it doesn't deteriorate with time (my car will be sitting round idle occasionally), it isn't poisonous, and it doesn't dissolve paint. There are disadvantages, but I think I know what they are, and can live with them.

TIA,

David

stephen_gusterson - 3/4/02 at 11:38 AM

quote:
Can anyone give me a rough estimate for the amount of brake fluid required to fill and bleed a Locost's brake system?


TIA,

David



If you want to be really nurdy, I recon you could calculate this.

You can measure the internal bore of the brake pipe, and its length, and find out the cylindrical volume.

The calipers / cylinders can be guestmated or calculated the same way.

Add a tad for the master cylinder, and your there.


Problem is though, is the wastage your gonna get when you are pushing any old stuff out thats being laying in the cylinder bores, and purging the air bubbles.


ATB

Steve

David Jenkins - 3/4/02 at 12:59 PM

quote:

If you want to be really nurdy, I recon you could calculate this.

You can measure the internal bore of the brake pipe, and its length, and find out the cylindrical volume.





No way, mate! Too much like work!

I'm look for an answer along the lines of "I bought a 500ml can and there's still a bit left over".

Keep it simple - that's my motto.

David J

stephen_gusterson - 3/4/02 at 07:35 PM

[quote


No way, mate! Too much like work!

I'm look for an answer along the lines of "I bought a 500ml can and there's still a bit left over".

Keep it simple - that's my motto.

David J




Buy a 500ml can - there's sure to be some left over......

will that do?

OR

write a program to run on a PIC that will calculate it for you



Being nurdy, worked out that a metre of brake tubing holds about 12cc of fluid (12ml).

If calipers are (big guess) 50mm dia by 50mm dia each, and two per caliper, thats 98cc per pot, approx 200 per caliper.

2x calipers = 400cc.

Rear cylinders are about 20mm dia and 60mm stroke?

6cc x 2 sides = 12cc.

so.

4 calipers = 400cc
2 cylinders = 24cc
7 mtrs pipe = 84cc
say 100cc for master cyl = 100cc

Thats a tad over a half litre, so we were both wrong.

I say go for a litre and try not to make bubbles (as they told Michael Jackson


)


ATB


Steve

chrisg - 3/4/02 at 08:32 PM

Stephen,

You have far too much time on your hands!!!

Cheers

Chris

stephen_gusterson - 3/4/02 at 10:03 PM

quote:
Stephen,

You have far too much time on your hands!!!

Cheers

Chris


Nah, just like to show off my meagure understanding of cylinder volume pi r2 h.

ATB

Steve





bob - 4/4/02 at 12:06 AM

The 500ml bottle and some left wil do for me thanks very much!!

David Jenkins - 4/4/02 at 07:15 AM

quote:
The 500ml bottle and some left wil do for me thanks very much!!


Me too, Steve.

I was going to make some rude remard about nerdyness and too much time, but I'm still in grovelling mode...

...and that joke about Bubbles! Groan!

David