cgfen

I changed the front pads on 997.2 2S this morning and decided to flush the fluid also since it had been in the lines since 2009.

Flush seemed to go fine, using motive power bleeder as pressure source and doing RR / LR / RF / LF calipers.

I used about 1 1/2 quarts of fluid.

I've done this successfully dozens of times on "older" cars.

BUT

Pedal is now very soft, as in it takes an extra 1" to 1 1/2" of travel before brakes actuate.

A couple of friends tell me that likely cause = need to have a Pcar "tester" attached so as to cycle ABS pump and then bleed out of RF caliper.

Anybody know if this tracks with your experience?
If so, any alternatives to going to indy shop that has the magic tester?


thanks

Craig

Fred R. C4S

I've used the motive power bleeder on several Porsches and never had a problem with a soft pedal. You have somehow gotten air into you system. All I can say is bleed and try again. I've never had to pulse the ABS unit.
Have you used the Motive before successfully or is this your first time?

USMC_DS1

Just bleed mine last week with the Motive. Do you have a bleed catch bottle? Check the tube that attaches to it for a split. GL.

Marine Blue

Do the newer calipers have inner and outer nipples or just the outer? On my old 928 I realized that both inner and outer nipples needed bleeding to get all the air out and a firm pedal. Anyone know?

mdrums

I use the Motive device to flush and or bleed on my 2012...never an issue. Sounds like you messed up and got air in the lines. Go do a through bleed again started with the passenger rear outside zero fittings 1st then to the drivers rear, passenger front and finish with drivers front. Use a whole bottle.

cgfen

Thanks for the tip

"I've done this successfully dozens of times on "older" cars."

thanks.
i suppose it's possible i screwed something up, but I also did a complete "reflush" as you suggest when i initally noticed the additional pedal travel.
no joy on reflush unfortunately.

cheers

Craig

997_rich

Also using the motive bleeder with great results. Not much different between my 05 911 and my 86 BMW e30.

If you've got a lot of air in the system, I've had good luck using a good old foot bleed. Usually, the foot method is best when you have a brand new system you've installed.

66mustang

My Indy who used to work at a dealership says they never pulse the ABS when bleeding. He used to motive on my car a month ago for a flush.

USMC_DS1

Do you have a durametric tool... that will allow you to pulse the ABS if you suspect air in the ABS. FWIW, I've yet to pulse my ABS even though I have a DM tool and have done 4 brake flushes over the past 2.5 yes.

stubenhocker

I dont think Durametric works for 997.2 models...

kosmo

do the brake work and feel proper after the 1inch of softness?

Is it possible that there was air in the System originally and that the flush pushed it out giving you the "soft" sensation?

vexed

Question for those who use the Motive--what pressure do you pump it to for bleeding the brakes on a 997.2? Thanks

PJorgen

I'm a bit conservative, don't want to blow up the system so I pump to only about 15psi. Have heard you can go as high as 25 but I won't do that.

15 works fine, maybe takes a little longer but I figure you should not rush brake work.

slicky rick

There must be some kinda of spec for this. For mercedes benz it 2bar which is about 25psi. Might be a standard? But of course words from our tech guys will be more credible.

997_rich

I use about 20. I usually have to pump it up a few times through the process so it drops as I flush. The real danger is not that you're going to run the system but that you're pop the reservoir off the master cylinder which would be a mess. the reservoir never sees pressure in normal use.