Nathan Lewis

I tried flushing my own brake lines on my 996 Turbo. The brakes worked, but felt mushy, so I was hoping I could improve it. After finishing the job, I now have no brake pedal feel, it goes all the way to ground with no braking at first. I suppose it acts like I have air in the line, because when I pump the brakes for a while it will build up some pressure and work. But the pressure drops off in less then a minute to nothing. Also, it seems like I can pump the brakes while the engine is off, but when I start the engine I immediately lose all the built up pressure.

I used a motive power bleeder, with 10-15 psi on each line, (I read one source where it said you should use about 30 psi for a PSM car) and I bled in the order of RR, RL, FR, FL, which I saw from some source online was incorrect. It said I should have done the FR last instead of FL.

Two other oddities: (1) I got quite a bit of air bubbles coming from the FL (the last one I did), but continued to bleed for some time after the bubbling stopped; and (2) when I pushed the car out of the garage to start working on it (because my wife took my keys that morning), I had no brakes then either. I thought this was odd, but thought it might be normal. (Its probably the first time I ever rolled the car in neutral with the engine off) I chalked this up to the engine being turned off, but I don't know could something have happened maybe to the master cylinder while the car was just sitting there? That would be a very odd coincidence.

did I do the flush procedure wrong? What should I do to fix it? Im afraid to even try driving to the mechanic.

Fishey

So, the procedure is pretty strait forward but a few things I would do before giving up. (I should note that I do not put any fluid in my motive bleeder)

Please note inside and outside bleeders for all calipers.

First, remove motive bleeder and fill the reservoir to the top.
Second,install motive, Add pressure to 15psi
Third, Bleed RR and LR outside bleeder (Do not go below MIN level)
Fourth, remove motive bleeder and fill the reservoir to the top
Fifth, install motive, Add Pressure to 15psi
Sixth, bleed the RF and LF outside bleeders (Do not go below MIN level)
Seven, remove motive bleeder and flill reservoir to the top
eight, install motive, add 15psi of pressure
Nine, Do RR/LF/RF/LF Inside Bleeders only need a few seconds to clear the small amount of volume left in the caliper (Do not go below MIN level)
Ten, remove motive bleeder and put brake fluid to correct level

You simply cannot fail if you do this.

Nathan Lewis

Oh, I forgot to mention that I changed the front rotors and pads. But I would think the rears would stop me even if I messed up the front brakes mechanically.

Nathan Lewis

Thanks for that procedure. I've never seen that before. Does anyone know if it was normal that the pedal went to the floor when I first rolled the car out in neutral? The manual seems to indicate that I should have had some brake power then, even though the power brakes were not running.

"02996ttx50

not that this'll help as i think you have air in the lines..

but anytime you swap a rotor you have to pump the brakes ( duh ) before attempting to use them!

rmc1148

Sounds like a bad seal on a caliper piston but you should see fluid and if not master cylinder.

highlander

YES. Because you changed the pads, you pushed the pistons all the way back into the caliper. It takes a few pumps of the pedal to get everything seated.

I did exactly the same thing on my Boxster. Almost ran through the garage wall pulling back in.

Good Luck!

Third-Reef

You pushed air into your system by letting the resivour get low. Probably why you got all those bubbles. Now you need to re bleed the whole system. My humble opinion.

z06801

^
This and check for a leaking bleeder

Nathan Lewis

Just to clarify, I rolled it out in neutral and the brake pedal went to the floor BEFORE we even started working on it. I am wondering if the 996 turbo does that normally (then it is probably just air in the line), or if by some coincidence there was a problem before we started (then it might be something else).

rmc1148

Read my post after bleeding is done properly you should have a full firm pedal. Get someone to pump the brakes and do it the old fashioned way and watch for air. Probably what I mentioned earlier but without being there its a guess.

911 Rod

So you are saying it had no pressure before you even took the wheels off?

How was it the last time you drove it?

Nathan Lewis

Right, when I pushed it out of the garage to start working on it, in neutral, with the engine off, I jumped in to stop it and hit the brakes and they went to floor. I had to stop with the e-brake. The only thing I did prior to pushing out out of the garage was open the brake fluid reservoir to look at it. I've been driving it with a mushy pedal for 6 months or so (since I bought it), but it stopped it fine until that morning.

Warehouse33.net

Have you checked for leaks around the master?

-Jason

Nathan Lewis

Yes, I checked thoroughly all around it and it is dry as a bone. I tried to check the calipers without removing the wheels and didnt see or feel anything wet.