Center exhaust flange bolt snapped off

[dphatch]

Can someone tell me how the bolts/studs on the muffler flange that attaches the center mufflers to the exhaust manifolds are attached ? Are they press in studs or just bolts ? Snapped one off and need to replace. If pressed in can they be replaced without removing the center exhaust from the car ? if so and tips and same would be appreciated.

[Loren]

These are on the cat pipes where they connect to the headers. (correct?)

900 075 365 02 M8 x 30 screw -- US MSRP $3.44 each

I suggest new gasket(s) and nut(s).

997 111 113 00 Gasket -- US MSRP $6.90 each

999 084 052 02 Nut -- US MSRP $4.52 each

[dphatch]

Correct. So they are screws and should be extractable from the cat side of the flange ? Any reason not to use upgraded SS blots and nuts ? Will a high quality antiseize hold up to the heat over time to be of any use ?

Edited November 12, 2013 by dphatch

[Loren]

Not sure about SS screws here - usually exhaust screws are alloy that can handle very high temperatures. SS is rated at <1000 degrees F whereas alloy bolts go over 1300 degrees or more.

I would for sure use the Porsche locking nuts though - you don't need the nuts walking off.

[dphatch]

Thanks, will stick to the Porsche parts as you suggest. Maybe one of the discount Posche parts guys can save me a buck or two on 'em. Never ceases to amaze me what Porsche charges for stuff as simple as nuts and bolts. As always your informed guidance is appreciated.

[dphatch]

As an update to my original post, finally decided to get under the car and inspect the flange bolts, or better put, studs and they are indeed what look to be pressed in studs. They are not hex head screws as I was hoping. see pics... I know what the PET shows but that must be for replacements. The originals are pressed in studs. So any suggestions for the DIY'er or do I take the cats off and have all the studs pressed out ? Anyone ever try drilling these out ? don't have access to a torch so that's not an option.

Edited November 12, 2013 by dphatch

[Loren]

Usually you can take a hammer (ball peen not a sledge) and tap these out.

The when installing tightening the nuts will pull the new ones into place.

[dphatch]

By "tapping " you mean mild pounding or the "hammers of hell" type pounding . Will soaking with PBLaster assist in the removal process ? Any reason the be concerned that the vibrations from the "tapping" will have any negative impact on the O2 sensors given their close proximity?

Sorry for all the questions put my brain works best when it isn't questioning what my hands are doing .

[Loren]

Sure a solvent should help loosen - and will burn off later.

They are just little spline shafted bolts.

[Dubbin']

When I was changing out my cats to go with a 200-cell X-pipe I knew some of those studs were going to snap. They just look flimsy. I should of soaked them with some PB prior to trying to remove them but I figured that I did not really need them either way. I ended up snapping 3 out of the 6 flange bolts.... I would of probably drilled it out and came through from the other end if I was in your shoes.... I would go ahead and PB blast the 2 other nuts, remove them and the whole cat section to be able to work on it from a work bench.

Good luck.

Mark

[RichS1963]

I recently had this issue. Bolts/nuts corroded and fell off leading to exhaust blowing. Exhaust system needed to be removed (bolts gas cut off) gaskets and clamps replaced.

Parts are £130.00 plus around 3 hours labour.

Had both sides done for peace of mind.

[pmfakelly]

I have the exact same problem.I stripped the rear bumper off and was going to try and get the left Cat out and on the bench but no joy.The other side is as bad with corrosion so both need to be removed and studs pressed out.

 

Did you replace with porsche parts or SS nut and bolts. 

 

I didnt expext a splined stud as the Diagram discribes it as a 30mm M8 Screw

 

thanks

 

pk

[Loren]

Whenever I work on exhaust bolts I expect them to break on removal.

Simply buy replacements ahead of time and save the stress - that's my advice.