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Resolution in post 9 (problem has been corrected).
Hi Guys,
Figured I'd cross post this from the 997 GT3 forum since the 997 C2S/C4S rear brake calipers are similar enough. TDLR of it is can someone go out to their car and pull one of the rear bleeder caps (not an issue on the front) completely off where it's actually in your hand and let me know if there's any moisture on the circular seat that goes around the base of the bleeder?
Assuming it's brake fluid there shouldn't be any liquid there, no. Two possibilities I can think of
-It could just be left over from the last bleed. When you're done bleeding the brakes and tighten the bleeder down there's still usually some fluid in the hollow upper portion of the bleed screw, and it can seep out over time
-Bleeder may not be fully tight. Assuming it's the same 10mmx1 thread as the 987/997 the spec is 6-9 ft-lb.
Assuming it's brake fluid there shouldn't be any liquid there, no. Two possibilities I can think of
-It could just be left over from the last bleed. When you're done bleeding the brakes and tighten the bleeder down there's still usually some fluid in the hollow upper portion of the bleed screw, and it can seep out over time
-Bleeder may not be fully tight. Assuming it's the same 10mmx1 thread as the 987/997 the spec is 6-9 ft-lb.
Thanks! Yes I removed any fluid from the upper hollow portion using a paper towel that I formed into that shape and got the remaining bit out. This came from the base of the bleeder. Going to have it re-torqued to be sure it’s good. If it still leaks I’ll have the bleeder or caliper replaced.
To update, retorqued to 9lb ft today. Cleaned area well. Appears fluid is not coming from between the bleeder and caliper but instead on the red threads shown below. I guess it’s possible that even after intense cleaning and compressed air that fluid remains in that cavity, but I’d be surprised. I’ll likely see if my dealer can get me in to pressure test everything. I’ve also never seen a leak from that area and have no clue what purpose those threads provide.
I see it in my 07 C2S. I cleaned it real well after the brake fluid flush, torqued to spec. Still there is very very slight seepage, enough to look like it’s wet. The funky thing is it does not puddle or anything. I even replaced all eight bleeder screws, same thing. It seems the aluminum caliper does not provide an absolute seal. I also see this same issue with my 2018 P4ST after I flushed the brake fluid, really annoying.
I see it in my 07 C2S. I cleaned it real well after the brake fluid flush, torqued to spec. Still there is very very slight seepage, enough to look like it’s wet. The funky thing is it does not puddle or anything. I even replaced all eight bleeder screws, same thing. It seems the aluminum caliper does not provide an absolute seal. I also see this same issue with my 2018 P4ST after I flushed the brake fluid, really annoying.
Never had any issue like this in steel calipers.
This is the exact info I was looking for. Thank you! So it does sound as if this could be "normal" even though any sort of brake fluid leak I wouldn't consider normal.
If anyone else is able to get outside to their car in the coming days to take a look that would be great. I'll likely make an appointment with the dealer. Normally I use independent shops but I could see this being a case where they have to keep replacing calipers until they find one that doesn't leak. A dealer making warranty claims will likely be easier than an independent shop doing so.
This is the exact info I was looking for. Thank you! So it does sound as if this could be "normal" even though any sort of brake fluid leak I wouldn't consider normal.
If anyone else is able to get outside to their car in the coming days to take a look that would be great. I'll likely make an appointment with the dealer. Normally I use independent shops but I could see this being a case where they have to keep replacing calipers until they find one that doesn't leak. A dealer making warranty claims will likely be easier than an independent shop doing so.
Again - thank you!
Originally Posted by Bxstr
To update, retorqued to 9lb ft today. Cleaned area well. Appears fluid is not coming from between the bleeder and caliper but instead on the red threads shown below. I guess it’s possible that even after intense cleaning and compressed air that fluid remains in that cavity, but I’d be surprised. I’ll likely see if my dealer can get me in to pressure test everything. I’ve also never seen a leak from that area and have no clue what purpose those threads provide.
What you see there is just overspray. The caliper was painted with bleeder screw already on. See the bleeder screws that I took out. It is one piece, not sure why you think that only the top of the bleeder screw turns. The bleeder screw is made of steel, so I think that the harder and softer materials just don’t mate well. I doubt dealer will do anything. Save your energy and just enjoy the drive.
What you see there is just overspray. The caliper was painted with bleeder screw already on. See the bleeder screws that I took out. It is one piece, not sure why you think that only the top of the bleeder screw turns. The bleeder screw is made of steel, so I think that the harder and softer materials just don’t mate well. I doubt dealer will do anything. Save your energy and just enjoy the drive.
Wow, cannot believe that I didn't realize this. Since I didn't watch those threads move when I torqued it, I just assumed that somehow the bleeder was separate from those threads below. I did make an appointment at the dealer so I will see what they say. My thinking is if brake fluid is getting out, that means water from washing can also get in which can't be good for the braking system. I will update the thread with what they say. Really appreciate your input and insight.
Resolution (problem has been corrected as I've driven the car 100+ miles without leaks and prior it was leaking even when the system was not under pressure): dealer installed four new bleeder screws (both outboard and inboard) with dust caps on both rear calipers along with Loctite 545 Thread Sealant.
If you're wondering why thread sealant compound is needed, that was a question I did not ask. The master tech did the work, who I've known for more than 10 years, has been working on Porsche's for 30+ years and is someone that I greatly trust. He also tracks his own sports car and has extensive experience on pretty much any Porsche. If he says to do something, I'm most likely going to listen to it. I went in letting them know that I replaced calipers in the past on this car and would be happy to do so again, even though it would be expensive. I also do not think that it is a feasible plan to just continue putting calipers on this car every couple of years or having to start swapping multiple sets of calipers onto this car.
Nope, they probably did use Loctite 545. It's a non-hardening thread sealant.
You really shouldn't ever have to use thread sealant on a bleed nipple as they don't seal by the threads. The way they seal is via the cone in the bottom, which seats into a metal base in the caliper. When you loosen the nipple, fluid can flow around the cone into that small hole below the threads, and then out the nipple.
So you shouldn't get seepage out the threads from a tight bleeder, but maybe that's just something inherent to these calipers, and were it me I'd probably keep an eye on it but not worry about it too much. It's entirely possible Porsche's torque spec on the bleeders is too low, but I'd be reluctant to experiment with that on my own given the risk of braking a bleeder or stripping a caliper
Nope, they probably did use Loctite 545. It's a non-hardening thread sealant.
You really shouldn't ever have to use thread sealant on a bleed nipple as they don't seal by the threads. The way they seal is via the cone in the bottom, which seats into a metal base in the caliper. When you loosen the nipple, fluid can flow around the cone into that small hole below the threads, and then out the nipple.
So you shouldn't get seepage out the threads from a tight bleeder, but maybe that's just something inherent to these calipers, and were it me I'd probably keep an eye on it but not worry about it too much. It's entirely possible Porsche's torque spec on the bleeders is too low, but I'd be reluctant to experiment with that on my own given the risk of braking a bleeder or stripping a caliper
Thanks for the info - yes, I agree that thread sealant shouldn't be necessary. However, since this is the second time this has happened, I'm assuming that there is a tolerance that is off in Porsche's manufacturing process to not allow the cone to actually seat properly at the bottom of the base in the caliper. The front calipers I've never had an issue with and the rears this is the second time this has occurred on calipers with 1000 miles on them (purchased brand new from Porsche). Regarding the type of Loctite, I am going to reach out to the tech to get info on what he actually used. I agree that 545 seems more likely, although both are listed as a thread sealer.
574 is an anaerobic flange sealant. It's designed for flat metal-to-metal surfaces with tight tolerances and would be completely the wrong product for this application. I'm sure they used the 545.
574 is an anaerobic flange sealant. It's designed for flat metal-to-metal surfaces with tight tolerances and would be completely the wrong product for this application. I'm sure they used the 545.
@MrMoose you are correct, the tech confirmed that 545 was used. They put the 574 part number on the invoice since Porsche didn’t have a 545 part number and he needed to charge it out to something. Like I said, it was noted in the description of work that 545 was used. Glad I checked.
04-15-2022, 04:21 PM
Bleeder Screw Cap
