Case through bolts o rings

[mb911]

So this has been covered many times but wanted a fresh opinion.. I just put the case together and found a few of the blue o-rings squeezed out. I used dow corning 111 on them prior to torque.. So what would be suggested at this point? Will viton really work that much better?

[faapgar]

Change to the red O-rings from Porsche.Fred

[smokintr6]

No personal experience with the blue ones, and my 964 thru bolts are a little different style.... but, I went with the green ones, and installed using a modified sharpie marker cap. No hassle, and no leaks so far.

[mb911]

I suppose I should order some.. Gotta find a part number..

[MBruns]

I have seen that alot when the edge of the through bolt hole is not chamfered enough or at all, I use a counter sink tool to break the edge and that gives the "O"ring room to work, I prefer the viton rings with most any lube, anything but sealant. The mag cases seem to shuffle at the washers that usually needs to be spotfaced when the cases are apart, I have seen the later cases that have one half chamfered and the other side not.
Mike Bruns

[mb911]

So would suggest replacement of all of them?

[MBruns]

If its squeezing material out yes, the rings are basicly packing but they seal main galley oil pressure and an awful lot of work beyond where you are now
Mike Bruns

[mb911]

Best source for quality replacements.

[MBruns]

Our host should have viton or a local hydraulic shop can match them up
Mike Bruns

[mb911]

Originally Posted by MBruns

Our host should have viton or a local hydraulic shop can match them up
Mike Bruns

Thanks.. Do you happen to know the correct sizing?

[gtc]

I used 8x2mm viton o-rings from McMaster Carr.
https://www.mcmaster.com/#9263K169

[Henry Schmidt]

Green Viton from Wrightwood Racing are the best we've found.

[bpu699]

Originally Posted by mb911

So this has been covered many times but wanted a fresh opinion.. I just put the case together and found a few of the blue o-rings squeezed out. I used dow corning 111 on them prior to torque.. So what would be suggested at this point? Will viton really work that much better?

Howdy Neighbor... (Live in Caledonia, see you are in Burlington)...

Looks like lots of folks chamfer the case to accept the rings. Home depot sells a 3/4 chamfer by Ryobi for $8. I put it in a very low speed drill, and applied very little pressure to "barely" chamfer it. Then sanded the edges with 1000grit sand paper to smooth the edges.

Waynes Book recommended this (chamfering)...

I do wonder why porsche only did it on one side. There had to be a great reason. Only think I can think of, is that on one side the o-ring seats against the THREAD, not a flush bolt surface. Perhaps they were worried that chamfering would take away needed compression against the thread? Applying gasket material at the thread end seems to make sense, but I know most folks just use o-ring lubricant.


Bo

[gtc]

The real question is.... Silicone or Krytox?

[Henry Schmidt]

Originally Posted by bpu699

Howdy Neighbor... (Live in Caledonia, see you are in Burlington)...

Looks like lots of folks chamfer the case to accept the rings. Home depot sells a 3/4 chamfer by Ryobi for $8. I put it in a very low speed drill, and applied very little pressure to "barely" chamfer it. Then sanded the edges with 1000grit sand paper to smooth the edges.

Waynes Book recommended this (chamfering)...

I do wonder why porsche only did it on one side. There had to be a great reason. Only think I can think of, is that on one side the o-ring seats against the THREAD, not a flush bolt surface. Perhaps they were worried that chamfering would take away needed compression against the thread? Applying gasket material at the thread end seems to make sense, but I know most folks just use o-ring lubricant.


Bo

I've seen this particular case and the sealing surface is in tact and not in need of chamfering. Some mag case definitely need work.

[BartdeBruijn]

Hi Ben,

Quite some time ago I ran into the same issue/problem....
After all maybe it is not strange at all that they do squeeze out(a bit)

cheers,
Bart

[mb911]

I was able to order the correct seals all is good now. Thank you everyone.