DIY: Brake Flush

[FTD]

Here's the pdf.

[Fletch986]

Thanks for taking the time to do this write up. I'll be doing my own 60k service and this will help.

[Tool Pants]

I take it in steps 2 and 3 the Motive is dry and you are using the Motive to reduce the level in the reservoir so you do not have to remove the screen to suck the fluid out.

[986Porsche986]

According to this tutorial, you are to use the empty Motive to push ALL of the old fluid out of the system and into a waste bottle at the rear right bleed valve until you hear the sound of gurgling air coming out of the valve. Wont this method allow air into the system? I have read other posts where this method is also used, but just enough to only lower the fluid in the reservoir to just above the sensor, then start bleeding with a filled Motive pressure bleeder. Can any "experts" chime in and let me know if the method in the attached PDF is incorrect? Thanks.

[Adam]

Originally Posted by 986Porsche986

According to this tutorial, you are to use the empty Motive to push ALL of the old fluid out of the system and into a waste bottle at the rear right bleed valve until you hear the sound of gurgling air coming out of the valve. Wont this method allow air into the system? I have read other posts where this method is also used, but just enough to only lower the fluid in the reservoir to just above the sensor, then start bleeding with a filled Motive pressure bleeder. Can any "experts" chime in and let me know if the method in the attached PDF is incorrect? Thanks.

Yeah, you don't want the resevoir to go empty or there is a very good possibility air will get in the system.

[jmatta]

Woah!!! Stand back, young man. Do not bleed to the point where you introduce air into the system. It takes forever to get it out, especially in a modern car. I've been tracking 911s for years and do my own brake work. The Motive is a great product, but always keep an eye on the reservior. I would be hard pressed to drive any car that got that much air in the system.

I'm sure Tool Pants can chime in to let us know what that much air does to the master cylinder, let alone the ABS system.

[JFP in PA]

Originally Posted by jmatta

Woah!!! Stand back, young man. Do not bleed to the point where you introduce air into the system. It takes forever to get it out, especially in a modern car. I've been tracking 911s for years and do my own brake work. The Motive is a great product, but always keep an eye on the reservior. I would be hard pressed to drive any car that got that much air in the system.

I'm sure Tool Pants can chime in to let us know what that much air does to the master cylinder, let alone the ABS system.

Getting air into the ABS system requires the use of a PST II/PIWIS diagnostic unit to get it out..................bad idea.

[wconley]

One comment/question regarding the pressure bleeder. The write-up suggests 20psi but I've heard that 14-15psi is as high as you want to go to protect the seals. Is it that 14-15psi is overly conservative? I've bled my M3 many times with 14psi with no problems but haven't needed to flush the Boxster yet. Thanks, and good write-up.

[Swahealy2]

FTD that was a great pdf you posted on brake bleeding. Thanks

[Frodo]

Maintenance newbie question. Never having done any brake work myself before, I figured it was time I started. What’s the consensus between this (FTD-posted PDF) and the PedrosGarage technique (see http://www.pedrosgarage.com/Site%203/Bleed%20the%20Brakes%20%26%20Clutch.html )?

One difference I noticed is that the PDF discussion has you pump out the fluid first, then lower the pressure, disconnect the line from the master cylinder reservoir, pour in the new fluid into the reservoir and the power bleeder, then pump it back up to fill the lines. Pedro just has you start out by putting the new fluid into the power bleeder before pumping it up and clearing the old fluid. Intuitively, Pedro’s technique seems to make more sense to me: easier, and less likely to introduce air into the system. Also, the Bentley manual seems to agree with this approach. And the comments above would seem to support that as well.

Any consensus on the 15 psi vs 20 psi? Bentley says "14-29 psi" so I would think 20 would probably be fine (?)

Pedro recommends alternating between the Blue Racing fluid and what he calls the Gold, to help you visually know when the old stuff has been replaced by the new. I assume what he calls ‘gold’ is the ATE TYP 200 Amber Brake Fluid. (See http://www.tirerack.com/brakes/ate/ate_type200_amber.jsp ) Right? Once you’re finished and out driving, is there any different ‘feel’ between these two products?

Finally, is online the best/only way to get this brand of brake fluid?

Thanks in advance.

[JFP in PA]

Originally Posted by Frodo

Maintenance newbie question. Never having done any brake work myself before, I figured it was time I started. What’s the consensus between this (FTD-posted PDF) and the PedrosGarage technique (see http://www.pedrosgarage.com/Site%203/Bleed%20the%20Brakes%20%26%20Clutch.html )?

One difference I noticed is that the PDF discussion has you pump out the fluid first, then lower the pressure, disconnect the line from the master cylinder reservoir, pour in the new fluid into the reservoir and the power bleeder, then pump it back up to fill the lines. Pedro just has you start out by putting the new fluid into the power bleeder before pumping it up and clearing the old fluid. Intuitively, Pedro’s technique seems to make more sense to me: easier, and less likely to introduce air into the system. Also, the Bentley manual seems to agree with this approach. And the comments above would seem to support that as well.

Any consensus on the 15 psi vs 20 psi? Bentley says "14-29 psi" so I would think 20 would probably be fine (?)

Pedro recommends alternating between the Blue Racing fluid and what he calls the Gold, to help you visually know when the old stuff has been replaced by the new. I assume what he calls ‘gold’ is the ATE TYP 200 Amber Brake Fluid. (See http://www.tirerack.com/brakes/ate/ate_type200_amber.jsp ) Right? Once you’re finished and out driving, is there any different ‘feel’ between these two products?

Finally, is online the best/only way to get this brand of brake fluid?

Thanks in advance.

Do not run the Motive unit higher than 12-15 PSIG; the ATE Blue and 200 are exactly the same product except for the dye coloring..............

[Frodo]

Two other questions come to mind: (1) Is it a given that when you flush the brakes you should flush the clutch as well? (as the Pedro's Garage article seems to suggest.) And, (2) Is 1 L of brake fluid definitely enough?

[JFP in PA]

Originally Posted by Frodo

Two other questions come to mind: (1) Is it a given that when you flush the brakes you should flush the clutch as well? (as the Pedro's Garage article seems to suggest.) And, (2) Is 1 L of brake fluid definitely enough?

Yes to both questions. Be sure the clutch pedal is held to the floor when bleeding the clutch. If you are careful, one liter will do the job; and do not over pressure the Motive bleeder, 10-15 PSIG is fine, but going too high can lead to issues......