Luis A.

Hi guys; in reading and trying to summarize the current state of communal knowledge about the best technique to avoid leaks, I came across two conflicting posts from Greg from 2103 and 2018. Maybe the preferred technique has changed...?


In 2013 he says (bolding mine):
I, personally, got tired of leaks in this area. Every single one that I have to redo, happens on "my own time"...so I was forced to come up with a method that worked each and every time, flawlessly.

If you can "dream it up", I tried it. Silicone gasket with and without sealant. Paper gaskets, with and without sealant. Different sealants, different gaskets.

I use the red silicone factory seal, a factory "paper" gasket (same part number as used in the rear), and use a thin layer of Porsche factory Drei Bond on both sides of that gasket.

Never have had one leak with that combination....been doing it this way for about 6-7 years now.
__________________
greg brown



On 7/27/18 he says (bolding mine):
Quote:
Originally Posted by merchauser
Reinstalled water bridge and added the paper gaskets to the O rings as recommended in a Porsche bulletin.
No leaks before, but now I have a seeping (minor leak) at the center O ring. It seems that the thick paper gaskets
have added some height to the water bridge and the center O ring is not seating all the way down. with WB installed,
I can see a very fine line of the black center O ring; don't think that was visible before.
anyone else had this issue after adding the thick paper gaskets???

The surface where the big O-ring sits has to have been "eaten" up with corrosion....probably on both sides of the original O-ring (like 90% of the ones I see), if you cleaned this surface. If you didn't clean this surface very well, there will be raised corrosion "patches". Raising the assembly puts the new big O-ring right into the pitted aluminum surface or on the raised corrosion patches.

Leave out the paper gaskets and apply a very thin layer of Drei Bond to the two aluminum mating surfaces. Use something very slippery on the big O-ring (I use HSS.)

__________________
greg brown


So no paper gasket has proven to be reliable for averting leaks on that area? Or is it mostly a function of existing corrosion at the new big O-ring sealing area when the bridge is raised by adding the paper gaskets?

Thanks in advance for any and all knowledge -- Luis

Koenig-Specials 928

I know you're gauging for a response from Greg .
In the meantime I have the quote above in hard copy in my maintenance binder (not the 2018 one).
5 years ago when I performed my intake refresh I did what he suggested and no leaks. 4 months ago during my summer 2018 refresh I repeated the above instructions.
It works for me.

Luis A.

merchauser

I can only attest to my own situation; when I replaced my water bridge and added the gaskets, as thin as they may be,
the assembly was raised up enough that the center O ring would not fully seat.
the second time around, I removed the gaskets and used dreibond. Its been about 6 months and zero leaks for me.
if you search other threads, it seems like its 50/50 with some having issues with gaskets and some not... good luck!

Wisconsin Joe

Greg himself recently said something to the effect of:

(paraphrasing) I keep finding better ways of doing stuff. My technique keeps evolving.

So, if it were me, I'd use the newer technique.

Found it:
https://rennlist.com/forums/928-foru...fle-today.html

Posts 14 & 16.

928NOOBIE

The timing for this could not have been any better. I literally received my water bridge stuff from Roger this morning and as I was going through it had the exact questions..

I'ts finally above 60 here in KC so the dog and I are going for a nice long walk hopefully 3 or or more miles..I hope neither of us keels over!

Seriously this is great thanks everyone...

928NOOBIE

I think that's for the oil filler neck, yes and not the water bridge? My plan for the water bridge is to use drei bond without paper gaskets...I have the red O-rings from Roger and will be using drei bond without paper gaskets for the water bridge...sounds like no leaks and remove risk of the big O ring not seating....anyone disagree?

For the oil filler neck yes I'm going with the method in post 14 and 16 for the link shared...and thank you for sharing..feels like a number of us are doing this all at the same time which I think is the best way...we all can have this conversation and record our results and it makes it better for the next group of folks ...

Wisconsin Joe

Yes, it was specific to the oil filler neck.

But the concept that he refines and evolves his techniques applies to everything, I would think.

merchauser

^^^^^completely agree with you, joe. and the FACT is that Porsche issued a bulletin that you should add those paper gaskets.
you can't argue with those 2 bits of logic. makes good sense. it just didn't work for me. could there be a tolerance difference
between different years? clearly, some folks have added the gaskets and had leaks, and others have not.


getting long in the tooth, I did not accurately recount my story, in post #4; let me amend:
when I began this project, there were NO leaks at my WB. I had an issue with the oil filler and so the WB had to come off. on my first reinstallation,
I DID NOT know about the Porsche bulletin to add the paper gaskets, and so I did not. no leak. unfortunately, I made a mistake with the oil filler,
and had to remove the WB again. on that second installation, I installed the gaskets and while the oil filler issue was remedied, the WB now leaked.
joke was on me, but at the time, I wasn't laughing. lol so for my third, and final WB removal, I used the proper O rings with the dreibond. no leaks.

what is the better method? who knows. I only wish everyone gets a leak free set up, whichever way is chosen.

Michael Benno

Here is the TSB on where to use the paper gasket. As the TSB notes this applies to specific motors in the 1989 model year.

merchauser

^^^^^^^^^^^^^^^^^^I never read that as an individual model year (1989) bulletin, but clearly, that is what is written.
I read it as model year 1989 and up: wrong! great observation.

Captain_Slow

I recommend following Greg's suggestion to apply some Drei Bond. I used only the paper and red ring gaskets and I have a slow weep on the right side (left if standing in front of the car looking at the engine). It's literally a few milliliters of weeping after the engine cools, so not a big deal - but it bothers me after doing all the top end work. If/when I install a donor intake (after powder coating - long story) I'll redo the water bridge seals using Greg's method. On a positive note - the oil filler neck is bone dry.

Koenig-Specials 928

+1 on Drei Bond on the paper gaskets

Bigfoot928