g_murray

Ye velcum.

1/4 to 1/2 travel of the brake pedal itself. NOT the number of inches.
The reason is that all these years you've been pressing the brake pedal - the brake master cylinder has also been getting a workout - - but only a fraction of the cylinder has been 'worked'. If you press the brake pedal all-the-way-down -then you will now have the internal piston, in the master-cylinder, operate all-the-way-down. NOW! this, for the master-cylinder is 'new' territory! This means you are asking the piston (and the rubber piston-head) to pass over the inside of the cylinder walls - where it has NEVER been before. Exposing it to this new 'rough' area can cause the 'seal' between the piston and the inner wall to weaken - and, yep, you guessed it, cause the premature failure of the master-cylinder coz now it's not able to do it's job - which is FORCE fluid one way (and not have it sneak back thru a weak wall gap, the other way.) Capiche !

Conventional wisdom has it that whilst you're flushing - you start the car and let the engine idle for a minute or so - then switch it off. This (seemingly) has the effect of turning on the ABS pump and thus also getting (new) fluid to flow from the resevoir thru' the ABS piping.

Gerry

jhummel68

I never put fluid in the bleeder. It may take longer to bleed, but there is less cleanup. I just top off the reservoir after each wheel. When I bled the clutch, I had to fill the brake reservoir a few times. The pick up for the clutch is close to the top and will start sucking air even though the reservoir is close to full. I'd say you can get about 50 - 60 cc before the air enters.
I'm sure it is faster putting fluid in the bleeder. It's just my way; I'm not saying it is better.

IXLR8

Although I've never had a problem yet, thanks for reminding me of that. You can get a "step" inside the bore.

Its sort of like the driver that never takes it over 2000 RPM for 200K miles and then a new owner starts to shift it at the 7500 RPM redline.

I'll do that.

IXLR8

I was just thinking about that option; using the bleeder as a pressure vessel only.

Thanks to all for the input and great tips!

Falcondrivr

I just drain the fluid back into the bleeder and store it there. Been in there for over a year and hasn't damaged it.

Renaud Bizet

Since we are on that topic.

What do you guys do with ABD if you don't have the "hammer"?
I am familiar with bleeding the brakes/clutch on my previous Boxster with the difference of the pressure accumulator but my car comes with ABD, does anybody have any trick to cycle the fluid through it?

Thanks.

IXLR8

+1.

I forgot I had that option.

guardsredcab

Wow! Thanks everyone for your advice, experiences, pictures and further questions... It's all helpful. Don't know for sure the build date on my '95, but I'm pretty sure I have the overflow line (it has the tubing shown on the drawing, which is absent from the pictures Gerry posted). As per the Motive instructions, I hooked up the bleeder and tried to pressure up to 10 psi to check for leaks in connections. Vigorous pumping yielded 2 psi which dissipated as soon as I quit pumping. So, I need to stop it somehow. Appreciate the idea of clamping the end (near the front left jack point). That would solve my concern about damaging the line up near the reservoir. But, the idea of using vise grip pliers could also work... would spread the clamping pressure across a wider space. I'm just looking to replace the fluid. I wasn't planning on doing anything to affect the ABS, master cylinder or clutch hydraulic systems. If I just run fluid through the brake lines (at the calipers) and get the bubbles out, do I need to worry about these other systems? Again, thanks for all your input. Greg