advice on flushing brake fluid

[///M42 sport]

I'm gonna use a positive pressure system.

So the basic idea is to drain the brake fluid resevoir and flush the four lines right?

If I want to upgrade to stainless steel lines, do I just unscrew the old ones?

Also I read that if you have hydraulic clutches, its a good time to flush that system too. How do you do this?
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ZX14 VS HAYABUSA

[TIATO]

Positive Pressure - IOW you are going to pressure bleed right?

DO NOT empty the brake fluid reservoir before pressurizing the system. Leave the reservoir full. The new fluid in the bleeder bottle wil displace the old stuff in the reservoir.

If you empty the reservoir and presurize it, you will get air into to the ABS block and you will wind up with a car with no brakes. The only way to "bleed" the ABS block is to cycle it via actuation or taking it to the dealer and hooking it up to the computer.

As far as replacing lines are concerned, that is spretty straight forward, for the exeption of the two rear inboard lines. Dropping the subframe (partially or totally) is the only decent way to do it. Do the lines BEFORE you bleed . Also leave the cap on the reservoir. Leaving the cap on will create negative pressure (suction effect) and significantly slow the loss of fluid (meaning less mess to clean up). Like I said, never ever let the reservoir run low or dry as you may get air into the abs block.

Once you got the line done (probably the 4 easily accesible ones), then its a matter of simple pressure bleeding. Fill the bottle with some high quality Super Blue, presuureise the bottle to 10-15 psi and start bleeding the brakes starting with the rear right, then rear left, front right and left front. Keep checking the pressure bottle psi. so that it doesnt drop too low.

Last step is to bleed the clutch master cylinder, which is just like bleeding the calipers. If the CMC is not gunked up, then the fluid should come out at the same rate as the calipers.

One liter of brake fluid will be more than sufficient for the job.

Hope this helps.

Mario

[Charlie]

Positive Pressure - IOW you are going to pressure bleed right?

DO NOT empty the brake fluid reservoir before pressurizing the system. Leave the reservoir full. The new fluid in the bleeder bottle wil displace the old stuff in the reservoir.

If you empty the reservoir and presurize it, you will get air into to the ABS block and you will wind up with a car with no brakes. The only way to "bleed" the ABS block is to cycle it via actuation or taking it to the dealer and hooking it up to the computer.

As far as replacing lines are concerned, that is spretty straight forward, for the exeption of the two rear inboard lines. Dropping the subframe (partially or totally) is the only decent way to do it. Do the lines BEFORE you bleed . Also leave the cap on the reservoir. Leaving the cap on will create negative pressure (suction effect) and significantly slow the loss of fluid (meaning less mess to clean up). Like I said, never ever let the reservoir run low or dry as you may get air into the abs block.

Once you got the line done (probably the 4 easily accesible ones), then its a matter of simple pressure bleeding. Fill the bottle with some high quality Super Blue, presuureise the bottle to 10-15 psi and start bleeding the brakes starting with the rear right, then rear left, front right and left front. Keep checking the pressure bottle psi. so that it doesnt drop too low.

Last step is to bleed the clutch master cylinder, which is just like bleeding the calipers. If the CMC is not gunked up, then the fluid should come out at the same rate as the calipers.

One liter of brake fluid will be more than sufficient for the job.

Hope this helps.

Mario

I completely second this, this is what I did on Sunday.

Quick tip, make sure the little braided overflow hose on the side of the resevoir tank is on securely. Don't ask how I know to check that.

-Charlie

[nando]

also be careful not to overpressurize.. the seals on the resivior tank aren't very strong and you'll end up with a huge mess. don't ask me how i know this either.

[aaron_silva]

Thank you very much for the great advice. I will be doing this very soon also. :up:

Aaron

[Bill 84 318i]

I completely second this, this is what I did on Sunday.

Quick tip, make sure the little braided overflow hose on the side of the resevoir tank is on securely. Don't ask how I know to check that.

-Charlie

You mean the clutch hydraulic hose?

[Charlie]

I completely second this, this is what I did on Sunday.

Quick tip, make sure the little braided overflow hose on the side of the resevoir tank is on securely. Don't ask how I know to check that.

-Charlie

You mean the clutch hydraulic hose?

The cheaply attached braided hose on the side of the resevoir, that likes to pop off if the pressure is a little above 12 psi, yea, I believe it's the clutch hydraulic hose.

-Charlie

[///M42 sport]

so the resevoir for the clutch hydraulic cylinder is the same as the one for the brakes?

where does this system drain at?

The bentley doesnt describe it too well. :roll:
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Wholesale vaporizer

[franz]

it drains from each bleed screw, one at each caliper and one for the clutch.

[TIATO]

so the resevoir for the clutch hydraulic cylinder is the same as the one for the brakes?

The bentley doesnt describe it too well. :roll:

Thats correct. Most European car clutch systems share their fluid with the brake system.

While the Bentley manual is good, it DOES NOT explain a LOT of things well.

[65Matt]

Back from the dead to add some more info to a great post.

I had to replace my master cylinder and as a result, got air in the lines. I bled the brakes manually. The brakes worked ok, but not great. I read this post about air in the ABS, and so I went out on a deserted wet road and slammed on the brakes. I think this released some air from the ABS. I bled the brakes again and they work great now.