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PCCB's seems to drag...


pb12

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I checked mine this morning after seeing your post. I have a small amount of drag. I would say less than half of what yours seems to be. Not sure if this is normal for PCCB's. I would check your pad wear if you haven't already. If there is still more than 50% pad left you may have sticking caliper pistons. This happens on cars that sit long periods of time. If you are good at doing your own maintenance you could pull your calipers off of the disc's and run them out all the way. Then compress them back in all the way. You may be able to feel if they are sticking and it may free them back up by moving them through their full travel.

Hope I helped and if you find the problem or if this is normal please let me know.

Jermmy

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Jermmy --

thanks very much for your reply! I just purchased the car from a gentleman who owned the car for 18 months and drove it less than 2500 miles in that time, so I think it fits your explanation. I have no problem pulling them off and running them in and out. Im thinking compressed air. Do you have a better idea of how to do it without popping the pistons all the way out?

thanks again

michael

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Hi Michael

I saw your post on Rennlist after I responded. Sounds like you have been going round and round with this problem. I'm not sure the best and proper way to travel the pistons. I did it on my bike with a block of wood that was thinner than my rotor. Basically you put the caliper in a vise with soft jaws to hold it in place. Then with the pads in place put the block of wood in and compress with air as you mentioned or with a hydraulic pump like I did. I used the pump so I could keep them lubed with the brake fluid. Once you have them compressed, bleed the pressure and use the wood to push the pistons back in. Sounds like you're pretty hand so you may find a way that works better for you.

As for the brake dust you mentioned in your other post. I think the PCCB's put off more dust than steel. I was disappointed because I was told they didn't put off much dust. The dust is gray and doesn't show up as much but I have black wheels so you see it right away.

Your statement about the GT3 being a different animal is very correct. I've had several Porsches and it is different in almost every way. I've had mine for about 2 years now and I still learn new things about it all the time. I think I know more about it than my dealer now. They never see them and it takes a specialist to trouble shoot them.

Good luck and if it doesn't work with the first one I wouldn't try another. I would rebuild it. Stick with the first one until the problem is resolved. If that doesn't solve the problem then it may be a master cylinder problem. But I believe the GT3 may have a front and rear master cylinder. I not sure though so you need to research that.

Keep me posted

Jermmy

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Jermmy

Thanks again for the input. I was kind of dissapointed by the seeming lack of DIY folks onthe Rennlist GT3 board. Brake systems are not the most complex things out there, and I have no problem pulling the caliper off and messing with it. I wont have a chance to do it before this weekend though as i'm out of town for the next several days. I just need to figure out the best way to do this without pushing the pistons out too far.

I really hope you're right with your idea. Just the rebuild kits for each caliper is over $225(!). $225 for 6 little seals and 6 rubber cups?! C'mon....

RE: brake dust, thanks for your input, yours is the first real world input ive seen. Glad to hear its "normal"! ;)

Michael

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Hi Phillip

Wish I could say the same. Maybe it's just because I have gloss black wheels or maybe it's because I drive this car harder than my old 997. Either way, after only 100 miles my wheels are covered in a light colored powered. I agree that it is easier to wipe off. If I had silver wheels I don't think I would notice as much. I think Michael is talking about dust in the amount you would see from a track day, which is abnormal for everyday driving.

Jermmy

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Hi Phillip

Wish I could say the same. Maybe it's just because I have gloss black wheels or maybe it's because I drive this car harder than my old 997. Either way, after only 100 miles my wheels are covered in a light colored powered. I agree that it is easier to wipe off. If I had silver wheels I don't think I would notice as much. I think Michael is talking about dust in the amount you would see from a track day, which is abnormal for everyday driving.

Jermmy

At least you have a silver car and black wheels. I have BLACK car and silver wheels lol.. So everytime you wipe the brake dust off your wheels know that at the very same time I am probably wiping off my entire car (again)...Arrghh..

:cheers:

Edited by phillipj
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Well, this just turned into a bigger project than it needed to. I was moving each piston in and out, making sure they all moved smoothly, and i made the huge mistake of taking the last piston all the way out....very stupid. In my effort to get it back into the caliper, i tore the **** dust boot.

So, i have new dust boots on the way, but i have no idea how to get the old ones out. They seem to be pressed into the caliper, but i really doubt they are.

Anyone have a shop manual they could look at and tell me how to R&R the dust boots on PCCB calipers?

Thanks

Michael

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These things are really pretty simple as it turns out. the dustboots will pop off with a little persuasion from a very small screwdrive worked around the perimiter. too bad I tore the boot, as assembly is cake once you stop being a knuckle dragging idiot! :)

michael

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Hi Michael, sorry to hear about the problem. I don't have a shop manual but hear is a link to Porsches part break down pdf.

http://www.porsche.com/all/media/pdf/originalparts/usa/GT3-2_USA_KATALOG.pdf

You can also do a web search on the topic. I'm sure they are no different than any other Brembo caliper.

Also if anyone know the procedure it's Loren.

Jermmy

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Jermmy --

I ordered all new boots and o-rings, I figured why the heck not, they're not that expensive, might as well, "while im in there".

Wont be able to work on it for a week though, as parts wont arrive before thursday, and im out of town untile late friday night, and then leaving sunday, so not even sure ill get to work on it next weekend grrrrr My job is getting in the way of my main objective! :)

Thanks for the parts schematic as well, I could sit here and look at that for the rest of the night! I really wish someone around here had the workshop manual....

Michael

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  • 3 weeks later...

Hey guys, finally back around. I decided that I didnt think it was the master cylinder, because cracking the bleader screws on the caliper didnt release any built up pressure.

I decided Id rebuild one of the calipers to see if it improved the situation at all. Though the jury is still out as to whether there is actually a problem, I figured, what the hell, seems like a fun project.

The first issue was to figure out how to source the parts that were needed. The dust boots are easy, the dealer can order them no problem, and the part numbers are on the parts "fiche". Three different part numbers, for three different sized boots. Note each part number has two boots in the bag. My dealer ordered twice as many as I needed because they thought it was one boot per order. The stickier, (excuse the pun) issue is finding the inner seals. It seems there is no normal part number for them. I asked the dealer to call Porsche Motorsport, and see if they could help out. Turns out they do indeed have a rebuild kit that is made up of the inner seal and the six individual pistons. By the way, there is some confusion on the piston sizes for these calipers, (2007MY PCCB). For the record, they are 28, 30 and 32mm. The kit does not include the dustboots though, so make sure your dealer orders those separately.

IMG1193-10-X2.jpg

IMG1195-12-X2.jpg

Ignore those part numbers on the Brembo instruction sheet, those wont help you.

The inner seals are color coded:

IMG1194-11-X3.jpg

The only mildly tricky part to removing the caliper is removing the brake line from it. Do yourself a favor, and buy a 10mm Flare Nut Wrench. The nut on the end of the brake line is made of brass to be sacrificial, so you don't ruin the caliper if you cross-thread it when re-attaching it. It is very easy to round off the nut using a conventional open ended wrench, so don't. Conveniently, the spring holds the brake line quite nicely! Make sure you put some sort of cap on the ed of the line, or it will weep the whole time.

IMG1133-6-X2.jpg

With the caliper off the car I used quick release bar clamps to hold five of the six pistons in place

IMG1196-13-X2.jpg

Then gently using compressed air, and a piece of 2x2 to make sure the piston doesn't pop out too far, I eased the piston out. The 2x2 is the perfect size, as its big enough to approximate the width of the rotor, and missing pad, but small enough to move around easily. Plus, that is wood, its soft enough not to mar anything.

Once the piston is out, use a (very) small flat head screwdriver to gently pry the boot out of the caliper

IMG1197-14-X2.jpg

Next, with a small curved pick, remove the inner seal. It will come out easily, as it just lays in its grove.

IMG1198-15-XL.jpg

Now, note which seal you've removed, there are three sizes, as noted above, and they are color coded. (Old on top, new on the bottom)

IMG1200-17-X2.jpg

Now comes the fun, getting the new seal back into the caliper. First, thoroughly soak the new inner seal in brake fluid, and then work it back into the inner grove. Its not too bad on the 32mm piston, but the 28mm piston is a pain in the neck to work it back into the grove, and make sure its seated flush. There isnt a ton of room to work with, and of course I was wearing rubber gloves, (because brake fluid is just the most nasty fluid in the car), so it takes a little doing. Its not to tough, just be patient, and it will pop into place.

Next, grab the appropriate new piston, and lubricate thoroughly with brake fluid, then gently, but firmly press into the caliper by hand. Be aware that the inner seal you just put into place may be sitting slightly proud of the inner surface, and so the first time you try and press the piston in, it may wedge against the seal. Just pull the piston back out, and feel around inside making sure the seal is as flush as you can get it, then try again with the piston. You will feel a reasonable amount of resistance, but not an excessive amount, and eventually the piston will slide in.

Working by moving the clamps around, so you are always working on one piston at a time, it took about an hour to do the whole caliper.

Re-mount the caliper with fresh new caliper bolts, torque to 63ft/lbs, bleed the system, and enjoy your fresh new caliper.

For this project, it made a meaningful difference in the drag I was experiencing. Though it is still there, as on all cars it seems, it is not as much as it once was.

Hope this is useful for somebody. Let me know if I missed anything, or if anyone has a question.

Michael

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Nice write up Michael. Glad you are making progress. I think you are right about all of the PCCB's having some drag. Mine have about half the drag of what you show in your video. So if you are there now I think you have it fixed. Mine are 2 years old now and it is recommended to flush the brake fluid so that's what I will be doing soon too try to avoid the problem you are having.

Good luck with the rest of the project and keep us posted.

Jermmy

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