peavynation

Looked up a bunch of threads for my impending brake flush using a Motive bleeder.

Someone mentioned to cycle the ABS valves during the flush. I don't have a PST2 to activate the solenoids during the flush. Someone recommended flushing, then driving and stomping on the brakes to activate the ABS a few times, then doing a complete flush again.

I also read (on a 993 thread I think) that just starting the car will get activate these brake solenoids and allow a flow. Do the 996's work this way?

How important is this? I've not seen much info on this listed anywhere.

TIA!

AudiOn19s

REAL good question. I've never had brake feel issues on my 996 from doing flushes with my motive power bleeder the standard way.

However on my M3 I chased a soft pedal forever, rebuilt calipers, replaced lines, etc chasing what was ultimately air in the ABS system. Once I was able to use a dealer tool to cycle the ABS during the bleed process I finally got proper pedal feel back.

Andy

ivangene

so what do you need to cycle it? Durametric?

peavynation

I heard a PST2 since only the full monty Porsche computers can talk to the ABS and command actions.



Thanks for the feedback Andy, good to see the comparison between your bimmer and p-car.

Marc Gelefsky

I dont think Durametric will do that...

Just bought one, but it's in transit still.

DCP

On the M3, do you suspect that air got in the ABS system during your bleed sure that you shouldn't do a BMW bleed with a Motive?

adg44

I've never cycled the ABS pump on any of my cars when I've bled the brakes with a motive pressure bleeder.

On our E46 3-series, I have done this numerous times and the brake pedal is hard as a rock. I'd gather there is some air in the system in your case.

- Anthony

cardsrule

we learned this in class but i can't remember the year and model. i think its an early c4 but i will look it up in my notes later today.

DCP

That makes sense. I can't imagine how air would enter the ABS system just from bleeding that doesn't cycle the ABS valves. There must have been another problem with his car.

As for the OP, I must stress that I do not know, but I have always thought that the quantity in the ABS system is likely pretty small and since the brake fluids are compatible and I am changing fluid more frequently than is really needed, that it makes little practical difference to bleed without opening the ABS. On the same theory, I don't bother with the clutch line bleed either.

adg44

You should really bleed the clutch as well - it holds a decent about of fluid, and the clutch action is so much smoother if you regularly bleed the clutch. I do this on all of my cars when I bleed the brakes.

- Anthony

peavynation

Can I bleed the clutch using the same DOT4 brake fluid?

There is an article on renntech about bleeding the clutch and how doing it is slightly different than doing the brakes (must wait longer and slowly depress pedal, etc.).

ArneeA

The clutch and brake fluid use the same reservoir. So if you don't bleed the clutch fluid, you still have some old fluid in that line.

peavynation

I don't know how I missed this, but Loren on RennTech commented about this issue in his DIY for bleeding (which I read a couple times even! http://www.renntech.org/forums/index.php?showtopic=7064)

Someone asked why the Porsche does not have a bleed valve on the ABS valve manifold like this person's Lexus's, and Loren replied that Porsche uses a PST2. Then that person asked if that meant if they had to take the P-car to a dealer to get the ABS fully flushed out, and Loren replied:

"Most dealers do not both to bleed the ABS unless the system has been open (i.e. lines or components replaced).
I have a PST (and PIWIS) and and I usually do not bleed the ABS on my own car."

(I left Loren's typo in there, but it's obvious what he meant).

If it's good enough for Loren, it's certainly good enough for me!!

peavynation

Oh!! Thanks ArneeA!

My goal is to someday not be a P-car newbie.

adg44

Exactly.