Billman's Brake Fluid Gravity bleeding revised
#11
I'm looking to change my brake lines to SS. Should I do a flush first and then install my SS lines and add more break fluids? My master cylinder looks pretty nasty. I figure this way would be using more brake fluid, but will keep my lines clean.
#12
On a technical level, I disagree with #3.
I'm not sure to what level does Billman mean by keeping it full. I top it off after each wheel.
The difference between half-full or full is insignificant. The pressure driving the through the brake lines is a function of the density and the difference in height between the bleeder and the level of the fluid in the reservoir. I estimate that this is about 17", and the difference between constantly keeping the reservoir full is about 1", making it about a 6% difference in pressure. As a result, how full the reservoir has almost no effect on the speed at which fluid will flow.
I'm not sure to what level does Billman mean by keeping it full. I top it off after each wheel.
The difference between half-full or full is insignificant. The pressure driving the through the brake lines is a function of the density and the difference in height between the bleeder and the level of the fluid in the reservoir. I estimate that this is about 17", and the difference between constantly keeping the reservoir full is about 1", making it about a 6% difference in pressure. As a result, how full the reservoir has almost no effect on the speed at which fluid will flow.
#13
Originally Posted by dwight' timestamp='1355686145' post='22213762
On a technical level, I disagree with #3.
I'm not sure to what level does Billman mean by keeping it full. I top it off after each wheel.
The difference between half-full or full is insignificant. The pressure driving the through the brake lines is a function of the density and the difference in height between the bleeder and the level of the fluid in the reservoir. I estimate that this is about 17", and the difference between constantly keeping the reservoir full is about 1", making it about a 6% difference in pressure. As a result, how full the reservoir has almost no effect on the speed at which fluid will flow.
I'm not sure to what level does Billman mean by keeping it full. I top it off after each wheel.
The difference between half-full or full is insignificant. The pressure driving the through the brake lines is a function of the density and the difference in height between the bleeder and the level of the fluid in the reservoir. I estimate that this is about 17", and the difference between constantly keeping the reservoir full is about 1", making it about a 6% difference in pressure. As a result, how full the reservoir has almost no effect on the speed at which fluid will flow.
#14
Registered User
My point is that I don't believe it will speed it up significantly. "Fluid is weight, the fuller you keep it the quicker you will be finished," is at vague and misleading. It isn't harmful, but it isn't right either.
In practice, I do oil, trans, diff, clutch fluids at the same time as bleeding the brakes. The reservoir holds enough fluid that I don't top it off while bleeding a single corner.
First I clean out the reservoir like Billman says, then I:
1)Start the bleed
2)Change a fluid
3)Wait for the color to change.
4)Close that bleeder and top it off.
5)Repeat as needed for other corners and fluids.
If you want to babysit the reservoir and keep topping it off, that's up to you.
In practice, I do oil, trans, diff, clutch fluids at the same time as bleeding the brakes. The reservoir holds enough fluid that I don't top it off while bleeding a single corner.
First I clean out the reservoir like Billman says, then I:
1)Start the bleed
2)Change a fluid
3)Wait for the color to change.
4)Close that bleeder and top it off.
5)Repeat as needed for other corners and fluids.
If you want to babysit the reservoir and keep topping it off, that's up to you.
#15
It makes sens to me to drain the entire system to remove the brake lines, then once everything is installed, perform the gravity procedure. In this case your waiting for fluid to come out of each caliper, rather then just turning blue from the old to new fluid.
#16
Registered User
Having said that, as a whole, I wouldn't hesitate is recommending this to anyone looking to bleed their brakes. My issue is a very small technical point which can be dismissed as being trivial if you like.
#17
Nerds
Definition of someone who is anal retentive - Attention to such arbitrary detail that the person becomes an annoyance to others.
#18
Registered User
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16 Posts
My experiences with ATE Super Blu Racing (as it is called overhere) and ATE SL.6 made me use nothing but SL.6
It's a thinner fluid and IMO makes the ABS act quicker when its cold outside - that's when you need ABS the most.
Boiling points (yes, both) are slightly less than Blue, for DD-ing and spirtited (public road - occasional track day) driving you will not notice the difference.
For serious track days there are better fluids, btw for serious track days you need other pads & tires too.
Service life of the SL.6 is 2 years (3 years for Blue) but I change the fluid every 1 to 1-1/2 year anyway.
Whats left I use for the clucth - it really helps to smoothen the pedal down and up (with an ACT PP)
To everyone that now thinks: if Billmans says to change the fluid I will do this tomorrow SIR YES SIR!
(When Billman says "Jump" all you ask is "HOW HIGH SIR?")
It makes a difference to push (or turn) the pistons back in.
Less old fluid to stay behind and hide.
Sure, its way more work and mayby not for everyone but IMO it is worth it.
Open the bleeder - with hose attached ending is a jar filled with brake fluid - to not push old fluid in the lines while you push/turn in the pistons.
If one really wants to bleed fast one has to warm-up (*) the new fluid container too.
Added static pressure by higher lever is way way less of a benefit than thinner (because warm) fresh fluid.
(*) do so at your own risk!
Or only change brake fluid in summer.
Or in a heated garage.
Or...
Oh well..
It's a thinner fluid and IMO makes the ABS act quicker when its cold outside - that's when you need ABS the most.
Boiling points (yes, both) are slightly less than Blue, for DD-ing and spirtited (public road - occasional track day) driving you will not notice the difference.
For serious track days there are better fluids, btw for serious track days you need other pads & tires too.
Service life of the SL.6 is 2 years (3 years for Blue) but I change the fluid every 1 to 1-1/2 year anyway.
Whats left I use for the clucth - it really helps to smoothen the pedal down and up (with an ACT PP)
To everyone that now thinks: if Billmans says to change the fluid I will do this tomorrow SIR YES SIR!
(When Billman says "Jump" all you ask is "HOW HIGH SIR?")
It makes a difference to push (or turn) the pistons back in.
Less old fluid to stay behind and hide.
Sure, its way more work and mayby not for everyone but IMO it is worth it.
Open the bleeder - with hose attached ending is a jar filled with brake fluid - to not push old fluid in the lines while you push/turn in the pistons.
If one really wants to bleed fast one has to warm-up (*) the new fluid container too.
Added static pressure by higher lever is way way less of a benefit than thinner (because warm) fresh fluid.
(*) do so at your own risk!
Or only change brake fluid in summer.
Or in a heated garage.
Or...
Oh well..
#19
Billman do you have a picture of a poorly maintained brake piston? This may make some people pay more attention to the most important fluid in your car and often time least maintained