Bleeding brakes on PSM car w/ Durametric tool

I've done several searches and can't find much of a definitive answer to this issue, so I'm starting a new thread... Does anyone have any advice or instructions on how to properly bleed the brakes using the Durametric tool on a 996 with PSM? My '99 C4 had the master cylinder replaced and now has a soft brake pedal no matter what process we use to bleed the brakes. My independent mechanic uses a power motive bleeder and the Durametric tool, but even after updating the software, it doesn't seem to properly activate the PSM module to remove all the air from the system. I can't help but think we're missing or forgetting something basic here, or there'd be a dozen threads with the same complaint. Anyone know what to do here? TIA!

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I don't know. I've tried to do mine for the sake of completeness as well, even though I don't have a soft pedal. Durametric seems to do nothing. I hear a relay click somewhere when I activate it, but no actual action from the ABS pump or anything. So as far as I can tell that part of the software is worthless. I've read other threads where people have had the same result, contacted Durametric, and gotten nowhere.

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Yep, that's my experience, too. I guess it just amazes me that there's seemingly no way to properly bleed the brakes on these cars without going to the dealer or a shop with the full PST2 system. I've spent the last month watching people chuckle at this question like I'm just inexperienced, but nobody has been able to provide an answer. ...and I know the Durametric people are useless and just point the finger at someone else.

The only actionable advice some people have had seems to be that if you activate the ABS during driving, you'll free up some air that's in there, which can then be purged by pedal or pressure bleeding again. An easy way to do this is to brake hard on painted crosswalks or other painted lines when it's raining. Super-slippery and guaranteed to trigger ABS action.

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Ha, tried that. My neighbors already thought I was nuts before they witnessed me repeatedly launching my Porsche on my snow covered driveway and then slamming on the brakes. Maybe it made a 5% difference after re-bleeding? But that's probably just my wishful thinking.

Yea, but I want to know - how hard was it to install an ABS system on that 356 lowrider?

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^^ I'd like to know about the paint job? Who did it, & how much did it cost? Also, did it take a long time?

$20 worth of speed bleeders makes the 996 just as easy as any other car with $20 worth of speed bleeders. To those of you who are curious: thus far I have not been contacted by any of the mainstream protestant German churches about this blasphemous practice...which is nice. Further, my hands have not burst into flames, and no more portals to hell than anticipated have appeared. I even own one of those pump-em-up bleeder things - but honestly...speed bleeders.

What size are the speed bleeders you use?

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+1

Hey Jake - I'll state the obvious - there are two bleeders per caliper, correct? You're not forgetting the inboard one? Other than that, I have no input. Please update if you resolve the problem. I need to bleed my brakes soon too. Also looking for more aggressive pads. I think my 944s stop better...

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They're good for what they are, but they won't do anything to activate and bleed the ABS/PSM module after replacing the master cylinder and introducing air into the system. Nope, we're going in the right order and doing both bleeders. The pedal stays pretty spongy no matter how many times we do it. I should clarify that my question isn't really about doing a normal brake bleed--that's basically the same as on any other car. The problem is that on PSM cars, the normal bleeding procedure is not able to remove air introduced into the ABS module after replacing the master cylinder. The 'official' Porsche PST2 system handles this by allowing you to activate the module during the bleeding process, but there doesn't appear to be a way to do it manually. The Durametric tool claims to be able to do it, but it sounds like everyone is having the same experience using it as I am--the function appears to be there, but it doesn't actually do anything. Does this make any sense? I know how to get the air out of the brake lines, but I don't know how to get the air out of the PSM module. Other people have posted about the same problem, but I've never seen a solution.

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Oh, I should also clarify that you shouldn't ever run into this problem during a standard bleed job, only if you lose the 'prime' in the ABS/PSM module by running the system dry.

The Durametric tool does NOT have the ability to run the ABS pump or PSM pump on the 996. I went round and round with Durametric on this and other members here have done the same. They won't admit it but it cannot. Apparently it used to be able to but a few years ago after one of their software updates it lost this ability and they have not fixed the problem (and from what I can tell have no interest in fixing it). Currently when you try to activate it you just hear a "click" and nothing happens.

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Yes - I understood the idea of getting the Durametric to cycle the ABS module to get the air out. Just checking to be sure the obvious was not being missed. What about bench bleeding the master cylinder, you did this already? Have you tried doing the bleeding with the engine running? Not sure it would make a difference, but I think I had to do this on some of my DSMs. Or at least it seemed to help... Understood. Good information.

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Thanks--yes, this is exactly what I'm talking about. I see lots of posts about it but never a final solution. Our experience with asking Durametric is the same as everyone else's. I guess it's just amazing to me if the only answer is to take the car to a dealer just to finish bleeding the brakes. Yep, we did this. Been doing it with the ignition on, engine off.

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Might be worth trying with the engine running. Not sure it is the answer, but shouldn't hurt.

UPDATE: So I took my 996 to the Porsche dealer in Madison, WI on Friday and they had difficulty connecting to the PSM/ABS module. They could not properly bleed the system because their system didn't seem to be communicating with the module properly. They seemed stumped but ultimately recommended that I replace it entirely. They were pretty vague and didn't seem all that interested in working on a 20-year-old car. I'm reluctant to just throw parts at this problem but it seems like my only option at this point. If the ABS and PSM systems are actually working but just not communicating correctly with the Porsche and Durametric computers, which part would I replace? Any ideas?

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Sorry to hear this. I would agree on the Durametric software, When I bought mine, I called tech support because the "Targa" module didn't work. They want log files from their software using their utility, which also didn't work, I went round and round and because I couldn't provide files they wouldn't engage any more and of course my 30 Return was gone. I asked what files they needed and I'd get them,,, Couldn't answer that ? because their utility did it for them and they didn't know. Which I replied it didn't work anyway and you don't know what files you need ? I looked after using software multiple and there were no changes in Laptop files in last 10 minutes, which should have shown something. Worst money I've ever spent on the 996. I also would like to bleed my PSM car, but unless I'm missing something not possible w Durametric. Anybody want to start a suit against them for false /misleading ad?

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My independent mechanic went through the same crap with Durametric before I resorted to trying the dealer. I honestly never considered that the dealer wouldn't be able to accomplish this. As long as you haven't drained the system for something like a master cylinder replacement, you're fine to bleed them the old-fashioned way.

I would hold off before just replacing the ABS/PSM hydraulic unit if it was my car. Every time you start the car and drive over 3-4 mph the system runs through a self-test program and cycles the solenoid valves and the pump motor. If there's a problem it will throw a code and light up the ABS and/or PSM fault indicators on the dash. It may in fact turn out to be bad but it's odd that the dealer didn't find a fault code and the dash fail lights aren't coming on if that's the root cause. Are you sure the hydraulic lines for the front and rear brake circuit connections at the master cylinder were reconnected and retightened correctly? What about all the caliper bleed valves? Either of those could be drawing air into the system and you might not notice a tiny amount of brake fluid. Even though you bench bled the mc, did your mechanic do a good old fashioned stand on the pedal bleed? After checking the above, I would substitute in a known good master cylinder, re-bleed and see if that fixes it before I dropped good money on a new hydraulic unit.

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Yeah, I thought that was weird, too. Other than the pedal being pretty soft, the car functions 100% normally with no lights on the dash. PSM and ABS work fine. I will double check but have to believe they're tight because I'd notice the loss of fluid. Brakes have been bled the old fashioned way half a dozen times or more. The dealer said they ran $200 of brake fluid through in their attempts to diagnose. Gotcha, that would probably be a cheaper place to start. Thanks for the input.

Np, happy to help. FWIW, I chased a soft pedal problem before including swapping the hydraulic unit and the master cylinder in the heat of the moment between races, continuing to bleed the system like crazy over the weekend as the problem persisted. It turns out I had missed a rear wheel bearing starting to go which was causing just enough wobble to cause the rear pads to knock back and displace the fluid in the wrong direction. A good way to check for leaks at the mc connection is to tear a few strips of shop towels off, wrap them around the connections and hold them on with a zip tie or small binder clip. It may be a tiny bit of fluid weeping out you might ordinarily miss with a visual inspection but air can get into the smallest of spaces.

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Noted, but wouldn't the pedal feel start out normal and continue to get softer as fluid is lost? The pedal feel doesn't change at any point of the process.

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Yes, if you were losing significant amounts of fluid it would keep getting softer. Over time the fluid level in the reservoir would keep dropping too of course.