Bxstr

Resolution in post 14. Problem has been corrected.

Hi everyone,
TLDR: can someone pull off one of their rear bleeder screw caps (completely off the bleeder where they’re holding it in their hand) and tell me if there is any moisture on it? The area I am interested in I highlighted in red below. It’s at the seat of the bleeder.

Details: Couple years back I noticed a small leak on my passenger rear bleeder. After removing and cleaning the bleeder and still having a leak, I decided to replace both rear calipers. Calipers have been bled 2-3x since then. Just got my car back from a brake flush and wanted to remove the bleed dust caps to clean any remaining fluid in the bleeder. When I did this I noticed some moisture around the area I circled, which sits at the seat of the bleeder. I cleaned it and the entire bleeder area, put it back on and then removed again and noticed again a slight amount of moisture. I’m unsure if this is just residual fluid from the flush that is caught on the bleeder area or if this is an actual leak. This is on both rear calipers. Neither front caliper has this issue and appears to be a slightly different design in how the bleeder meets the caliper. I’m guessing that if this is an issue on all 997 GT3’s, most people don’t notice it given that people aren’t typically pulling off the entire dust boot and that is the only way you can notice it. Both shops that work on my car are very experienced in Porsche and the one that did the flush this past time was the one that informed me on how many times these leak due to people over tightening, so I have completely confidence in their work.

Thanks!

ngng

a little fluid is totally normal, I suspect some from the flush was left over

Bxstr

Thanks! Would you expect fluid to still be there after absorbing fluid from the bleeder screw hole itself along with cleaning multiple times around the perimeter of the bleeder screw? If there is a leak, should I start with having my shop replace the bleeder screw ($20/set of 2) or should I just go all out right away with a new caliper ($700/caliper)? It's just shocking to me that this would happen again with experienced technicians working on my car, which is what makes me wonder if there is a larger issue here of these calipers just naturally leaking some amount of fluid, which also seems like it wouldn't be the case.

ngng

If you've already cleaned everything and still see some fluid my next suggestion would be to check the bleeder itself. It should be snugged down. No need to go to town on it. Give that a try next. Calipers don't generally need to be replaced, even when beat on, they can be rebuilt. But, that's not what's going on here.

Bxstr

Thanks! Bought a torque wrench today. There was maybe another 1/8 to 1/4 turn until it was at spec of 9lb ft (6-9 lb ft is the spec). Then cleaned the area extremely well and dried it.

I do have a new discovery, it doesn’t appear to be coming from between the bleeder and the base of the caliper. Instead it appears to be coming from the red threads, circled in green which has nothing to do with the brake bleeding process, I believe. Is it even possible to leak there? I washed both rear calipers extremely well and then blew dry with air. Only the passenger rear, which is the one where I suspected the leak, still is wet when I pull out the bleeder nipple cover base. You can see the wetness in my second pic.

ngng

hmm, that photo kind of confuses me. What are those threads part of, the bleeder?

Bxstr

it’s a piece that doesn’t actually move when bleeding. Only the silver bleeder nipple moves. Those threads are built into the caliper assembly itself. Front does not have that design. Only rear. Super strange. I ask myself if there’s some residual fluid that I just couldn’t flush out when cleaning everything or if there’s an actual leak there. I’m probably going to have my dealer or shop pressurize the system and see if we get any leakage. That seems like the best next step since everything is now torqued and it doesn’t appear to be coming from the bleeder.

RAudi Driver

Those threads circled in green are part of the bleeder valve. It has to be as the bleeder valve has to house a ball bearing and spring in that area.

Looks like someone painted the threaded part of the bleeder valve. That shouldn't affect the bleeder valve to caliper seal unless you're now screwing the red painted threads into the caliper. If say that your bleeder valve turns and the threads stay stationary? I see a problem right there. I can't tell the thread diameter size by the picture, but would it possible that someone threw a time sert in that caliper?

Bxstr

Thanks! Someone else pointed out to me that the threads are part of the bleeder. Not sure how I didn’t realize that, probably since they were painted. I never paid attention to the threads, but I am guessing they moved as there is no issue with bleeding the brakes or tightening or loosening the bleeder.

Caliper is brand new as of 2.5 years ago. I bought new from a Porsche dealer. I have pics of these right out of the box and they looked identical. Brakes have been bled 3x in that time, one of those being when it was installed. The two shops that work on my car are specialized in Porsche’s and track cars.

If you get a chance, I’d be curious if the base of yours is wet at all, it will show up on the base of nipple cap that wraps around the bleeder. I posted this in the 997 forum and another member mentioned he has this on both his 997 and Panamera. Likely due to steel bleeder and aluminum caliper. Also read about a 996 Turbo guy who had this happen and the dealer had to install three new calipers before they found one that didn’t leak.

RAudi Driver

I looked at my RS, cayenne turbo and my GT3RS and all of them are bone dry.

ngng

I'd call your shop and ask and keep an eye on it. Personally, a little sweat wouldn't bother me. But, I understanding wanting it to not have any liquid. What's it look like after a drive?

Bxstr

Thanks! Appreciate you checking it. Strange that this has not happened on front, only rear calipers for me, even with brand new ones. I'll keep everyone posted.

If I clean the base of the cap and put it back on, it's immediately wet again. Maybe with half of a drop of fluid. If I go for a drive, like I did yesterday morning and checked it again, there's maybe a drop or two. Since brake fluid is obviously a more greasy material, it spreads quite a bit and looks like more than it actually is and won't evaporate. I do have an appt with my local dealer this week. Their master tech has been there 15+ years and has seen plenty of 997 GT products come through the door so I have a feeling he'll have an idea of what to do. Hopefully they can clean the bleeder, re-bleed that caliper and I can get some miles on it and see if it comes back.

Thanks again everyone. Will keep this thread updated.

ngng

Please report back. I'm curious what it is. Hopefully something simple like a bad bleeder.

Bxstr

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.

Bleeder screws: 99735291900
Dust caps: 93035192701

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.

bweSteve

assuming the word "Resolution" at the beginning of your post means that new bleeder screws (w/ loctite) fixed the problem