Brake Bleeding with PSM

I am about to refinish my calipers as a previous owner had elected to paint them while fitted to the car. Ugh. I will also do new seals and braided steel lines at the same time. However, reading the repair manual (I have the excellent Bentley manual), it calls for the use of a Porsche Scan Tool when bleeding the brake system on cars fitted with PSM (my car has PSM). From what I am reading, the scan tool activates the PSM booster pump and it pumps fluid to the calipers to enable the bleeding process. I'm certain others have bled their PSM brake systems. Did you use a Scan Tool to activate the booster pump, or can you simply use the brake pedal or pressure bleeder (I have one) to effect the bleeding process? Pelican Parts sells a Schwaben Scan Tool, but reading the reviews, it seems to be a 'hit and miss' tool as many complain of its inability to even reset maintenance reminder lights and the tool is not returnable except under warranty. Hard to imagine that a simple task like bleeding brakes has become such a complicated affair these days..... Thanks in advance for your thoughts. Bob

Just bleed it normally and don't worry about the small amount of fluid in the ABS/PSM circuit unless you have replaced these units and they are dry inside. AFAIK the Scwaben tool cannot activate the ABS/PSM pumps. Durametric Pro can't either, not on the 996.2, even though it is supposed to. I went round and round with Durametric on this, in the end they basically blew me off b/c they are not willing to admit that the function does not work. Supposedly it used to be able to but then it lost the ability with a software update, it does not appear they have any interest in fixing the problem.

Thanks, Nick. I suspected as much.. Bob

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2nd all this. Durametric has a button to activate the ABS pump for bleeding purposes, but it doesn't do anything. I've had all my calipers off to replace them, just did a normal bleed afterward. You can remove the calipers while barely losing any fluid if you're careful and have a couple spare parts on hand. If you have a spare bleeder screw, then just break the connection between the caliper's little mini hard line and the flex line (disconnect items 5/6 from item 7 below), and then screw a spare bleeder screw into item 7. Your hydraulic system is now sealed up and you can take your time prepping the new caliper to go on. So in your case, if you had 4 spare bleeder screws, or just quickly whip one out of each caliper as you remove them, you could seal up your whole system for days while you go refinish the calipers, and then reassemble it. The system will only be open for a few seconds at each corner while you unscrew each caliper and then plug the hose with a bleeder screw, so you'll only lose a few drops of fluid; not nearly enough to evacuate the ABS, reservoir, or anything else. Do a normal bleed after your refinishing to fully bleed each caliper, and you're all set!

Does anyone know of a cheap source for bleeder screws?

Not so cheap...but available https://www.pelicanparts.com/catalog..._pg2.htm#item4 Maybe check around a bit more

I found them for cheap at RockAuto. I just had to find the size first. M10-1.0 I'm not sure if they are the regular M10-1.0 or the shorter M10-1.0S, but for $1.38 each, I can get 5 of each. Why do they sell them in quantity of 5?

Great info, thanks guys... Need to bleed my brake calipers again next spring/summer as well with PSM and wasn't sure how to deal w/ this system. Cheers,

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Some people advocate for activating ABS via rough driving to "stir" any air bubbles out of the ABS system, and then bleed. I have done so and couldn't honestly feel any difference. It's pretty easy to activate ABS if you brake hard in the rain, especially if you can find some painted lines and clamp the brakes while your tires are on the paint. Do that several times prior to bleeding your brakes and I think you should have full confidence that you've gotten any air out of the system. No special tools required.

I broke the brake line from the hose to the caliper on my 2004, so I lost all the fluid. It took about a week to get the new line in and installed. In the meantime, I replaced the hoses with braided steel, so there was certainly ample time for fluid to drain. I got everything reinstalled, bled the system with a Motive Power Bleeder, and it all worked out just fine. I'm still bedding-in the pads and rotors (EBC Yellow Stuff and Sebro), so I haven't pushed them all that much, but the pedal feels fine. I was ready to order a Durametric in case I needed to drain the PSM circuit, but it ended up being a non-issue.

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haha. who knows but when you get them and you figure out which size let us know.

I have found, if you can slightly press the gas pedal and hold it down (i use a jack stand) it seals up the line from the top (like holding a finger over a straw) and much less fluid comes out, and then i put a brake bleed nipple cap on the end of the exposed hard line when removing calipers or changing brake lines.

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I think you mean the brake pedal.

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Same experience here, Bought the tool/cable, Did what I wanted as far as ABS,PSM reset, but when I went into Targa section, nothing worked as expected, called the tech support, They wanted me to send log files, (I do this everyday in normal job supporting multiple systems ) their app wouldn't connect to their server or pull from my application, I kept asking just tell me what file(s) your looking for and I'll send it via email, unwilling to do that, It was like it was some trade secret. I thought about sending it back but it's cheaper than visit to dealer. They kept blaming it on my network connection, 3 different WiFi connections, and wired Ethernet, which is funny as the same network connection allowed me to download the app. I finally gave up dealing with uncooperative software vendor and moved on hoping I never need it for the Targa Top The product does do basics well, but if you have something that a option on the chassis (Targa, Cab, PSM Brake activation ) or out of ordinary, your screwed. 3 out of 5 stars for Durametric, I wish they sold through Amazon, Love to see responses there. Rant over, Mike

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Sam here, I kept sending them LOG files which they requested. They said they would "work on it and get back to me". I followed up a couple times over several months and they said "still working on it" which clearly they weren't. I agree Durametric is great for basic stuff but this was one of the main reasons I bought one, so I could fully bleed the system including ABS/PSM. Too bad.

Brake caliper refinish has begun, thanks to the great advice on bleeding. A previous owner painted the calipers red and applied a Porsche decal. To say it was a shoddy job is paying him a very high compliment. Likely was one of those Autozone spray-bomb paint your caliper deals, and masking things off was seemingly not a high priority. There's overspray on many of the alloy suspension members that I'm removing. I also noted some surface rust on the exterior of the front strut, so some sanding and Scotchbrite work followed by a clean-up with Eastwood's 'Pre Cleaner' set it up for a refinish using Eastwood's excellent semi-gloss 'Underhood Black' finish. To remove not only the red paint but the black Brembo powdercoat finish, I used Eastwood's 'Down to the Metal' stripper. The stuff is magic. Apply it with a brush (as it is a gel) and let it work. Do not let it dry too long, and I hand wire brushed the paint off the calipers. They'll need some detail wire brushing with a Dremel, but 95% of the powdercoat came off. Neutralize the stripper with water and then when done, do a clean-up with 'Pre Cleaner'. I'll be refinishing the calipers with Eastwood's '2K' red spray. The 2K is a catalyzed spray can where you activate a catalyst inside the can by punching a plunger on the can bottom. I'll apply high-temp vinyl Porsche decals and then finish with Eastwood's 2K clear. I'll continue ot post pictures on my progress. But if you're wondering what a Brembo looks like under the various color finishes, it is a dark grey alloy.

I didn�t activate the abs pumps and bled just fine after having a caliper removed for an extended period. I�ve since tracked the car and had zero issues with pedal feel. If you don�t have one, buy a Motive power bleeder and a little catch bottle with the straw that goes to the bottom. These are some of the best investments I�ve made in my garage and make bleeding brake systems a breeze. Not to mention you save a ton of time and frustration by getting it right the first time.

I do have a Motive Power Bleeder, and the cap that fits our 996 reservoirs. Agree that it is an indispensable tool in the garage!

Very interresting thread. Im about to do the same work as OP next spring so this is really usefull. Thanks for the infos!

Here's a few photos. The first is the work done by a previous owner. Second is Eastwood's 'Down to the Metal' stripper, and the last is of a caliper after stripping. I still need to do some detail wire brushing with a Dremel, but as you can see, the stripper removed 98% of the paint and powder coating.

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Calipers were sprayed today with Eastwood's 2K Urethane Gloss Red paint. I did 3 coats and will let it set-up before installing the decals and then shooting with 2K Gloss. I'm really pleased with the finish thus far. Those are the old dust seals in place. Once finished and hardened, I'll remove the pistons, seals and dust seals with new pieces.

They look terrific. Nice progress. I need to refinish mine sometime. Prior track use cooked the clearcoat and the seals (I have upgraded replacement seals waiting to go in). I think I�ll follow in your footsteps. Subscribed!

And here is a finished front caliper after the application of high-temp vinyl lettering and 2 coats of Eastwood's 2K Clear. They look every bit as good as a powder coated piece for a fraction of the cost.

Yowzah, yowzah, you. Dang. How do you remove the pistons without damaging the work you've done?

Looking good. Where did you order your decals?

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First, I've removed the old dust seals by first scribing around them with an Xacto knife, and then lightly driving a pick into the outer perimeter of the seal and they pop right out. I'll use compressed air tomorrow with a block of wood in the middle of the caliper to pop them out. You want to control the pistons so they all come out equally. I'll clean-up the pistons of the overspray, place new seals and dust seals, lubricate the pistons and reinstall. Here's a photo of all 4 calipers finished and another with the dust seal removed.

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I sourced them overseas from www.acromann.com . They are high temp vinyl and come in various sizes. I elected to use a slightly larger decal. Bob

I have begun a new thread devoted solely to the refinishing process.....

Great job, very impressive.

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Knowing what you know right now, do you think covering the pistons would have been a good idea? I plan to rebuilt and re-finish my calipers the same way but I will probably re-use the same pistons so the internal bore size is important if I want to use pad dampers. Do you plan to use pad dampers? I also want to know what you will be using for pistons clean-up? Eastwood paint stripper? Thanks

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Not really. The paint on the pistons is confined to the surface that contacts the dampner. Easy enough to remove. I left the dust seals and pistons in place as removing them would have made masking those openings difficult if not impossible and likely would have introduced the possiblity of paint to the piston bores. Not a good thing. I do plan to reuse the pistons as the only wear point would be the O-ring inside the bore and the dust seal hardening over time/use and I know the pad dampners will mate with them. I'll post some photos of the rebuild today.... BTW, there was a fair amount of adhesive between the pad dampners and the pad backing plate, which is why I had to pry the pads out of the calipers. Generally pads pull straight out once the pistons are retracted. I've removed the adhesive and do not plan on putting any back in place. Actually, I have no idea how one would put adhesive on those surfaces and then insert the pads unless you secure the pads in the calipers first and then offer the caliper to the rotor; hard to imagine removing the calipers each time you change pads.... Bob

Perfect thanks! Im following your Caliper refinishing thread, very good job. I think the pads dampers have to be inserted in the piston first, you remove the adhesive backing and insert the pads after. That's in theory... in pratice I guess I will be a total pain in the *** with new pads and rotors but I will give it a try. Thanks for sharing all the info Hugo