Brake flush or brake bleed?

SurfDog · 04-28-2015, 08:00 PM

Quote:

Originally Posted by JARblue

This is wrong. The fluid does not mix in the lines except for very small amounts, which is bled out. With a power bleeder, the new fluid is pushed through the system forcing the old stuff out. With a gravity bleed, the new fluid is also forcing out the old stuff, but it is working solely by gravity and takes a lot more time. Either way, there is no need to run any more brake fluid through that line once the new stuff starts bleeding out. You're just wasting good brake fluid.

I've never needed more than 2x 500mL bottles of Motul RBF600 for a full brake flush, but I always buy three and use half one to flush the clutch system

If you are just refreshing your dot 4 (RBF 600 is great stuff) you are primarily trying to get the "wet" fluid out of your lines. brake fluid is super hydrophyllic (absorbent) of water (its designed to pull water out of your system), you need to fully flush your fluid as the water "travels" up the fluid column.

The primary reason to get the "wet" fluid out is that it lowers your brake fluid boiling temp from around 600 degrees down into the mid 400s. (track temps regularly are in the mid 500s)

Road and track crashed the 09 press 370 during track testing from boiling fluid (OEM DOT 3 fluid I believe)

The short answer: Use good DOT 4 fluid and FULLY bleed out your fluid to ensure its "dry" 2 bottles will get it done if your are perfect, so buy 3.

I bleed mine at least twice a year (during track season) and its very easy. Dont use a power bleeder unless you are a pro, just have a buddy pump you pedal for you. Power bleeders can damage the ABS system I've heard so are better left to pros. Manual bleeding is a quick job and very DIY easy.

JARblue · 04-28-2015, 08:09 PM

Quote:

Originally Posted by SurfDog

If you are just refreshing your dot 4 (RBF 600 is great stuff) you are primarily trying to get the "wet" fluid out of your lines. brake fluid is super hydrophyllic (absorbent) of water (its designed to pull water out of your system), you need to fully flush your fluid as the water "travels" up the fluid column.

The primary reason to get the "wet" fluid out is that it lowers your brake fluid boiling temp from around 600 degrees down into the mid 400s. (track temps regularly are in the mid 500s)

Road and track crashed the 09 press 370 during track testing from boiling fluid (OEM DOT 3 fluid I believe)

The short answer: Use good DOT 4 fluid and FULLY bleed out your fluid to ensure its "dry" 2 bottles will get it done if your are perfect, so buy 3.

I bleed mine at least twice a year (during track season) and its very easy.

Good stuff

Quote:

Originally Posted by SurfDog

Dont use a power bleeder unless you are a pro, just have a buddy pump you pedal for you. Power bleeders can damage the ABS system I've heard so are better left to pros. Manual bleeding is a quick job and very DIY easy.

I've only heard of problems arising with the ABS when excessive pressure is used. My research indicates that you should never go over 15 psi on any car, and some cars can't handle that. I've power bled the Z's brakes numerous times at 10 psi maximum. The power bleeder is far quicker and easier by myself than if I have a buddy to help pump the brakes

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