RallyJon

I have a set of motorsound mufflers coming this week. I peeked under the rear bumper yesterday and every screw and nut I can see is very corroded, and the hex screws holding the tips on and muffler to the cat looked partially rounded out. So, rather than get stuck in my driveway after cutting out a rusted bolt, I want to have new hardware on hand.

Everything looks to be standard sizes, so I was going to use McMaster instead of paying $10 a bolt from the dealer or getting FedEx from CA.

Anyone done this? Any of the nuts and bolts that are unusual and Porsche specific? I'm assuming the locknuts are the distorting type. Stainless steel is best?

Thanks! -Jon

Flying Finn

I've used regular stainless steel metric bolts & nuts when I changed the exhaust etc. with no problems.

RallyJon

Looks like it needs the following:

Tips and cat:
M8 x 65 - 4
M8 x 17 x 3 washer - 8
M8 locking nut - 4

Straps:
AM8 x 50 - 2
VF M8 locking nut - 2

Heat shields:
M6 x 14 - 4
M6 nut lock - 4

So what are "AM8" and "VF M8"?

Also, the how-to on pcarworkshop.com says that Porsche switched from hex head screws to cheese head screws at some point. Any reason for one vs the other?

TheOtherEric

Jon, I'm almost surprised you're asking such a basic question! Of course you can throw out the porsche bolts and replace them with non-porsche. I picked up some replacements at Home Depot; I even bought US sizes. Probably 3/8" bolts x 2.5" long. If you want stainless, you'll probably need to use a smaller outfit like www.boltdepot.com since McMaster usually just sells that stuff by the box. Considering the frequency at which I change exhaust stuff, I just used antiseize instead of bothering with stainless.

RallyJon

Thanks for the link--boltdepot looks like a good source.

I know it's basic--certainly anything would work for the donut connectors--but when I see strange descriptions in the parts manual for parts I haven't seen with my own eyes, like for the strap hardware, I figure it's better to ask.

TheOtherEric

Yeah, IIRC, the strap nut is a little captive dohicky that you wont' be able to find outside of porsche. I thought it was integral to the strap but I'd have to confirm that tonight (I just removed mine for obvious reasons...).

RS man

The muffler strap's nut is integral to the strap. The bolt can be replaced with any metric hardware. I used stainless bolts to replace the factory ones.

Harry

Garth S

The 'special' designation for the muffler strap bolts may acknowledge the allan head bolts used, vs std. hex. The former spins more easily in the crotch of the strap ....

RallyJon

Ahh--here's where I got confused: my straps look neither like the parts diagram (which shows the bolt coming in from the top into some sort of square captive nut), nor like the photo on pcarworkshop here: http://www.pcarworkshop.com/index.ph...ng_the_Muffler

Mine:

NP993

Make sure to add to your list a tube of hi-temp anti-seize paste. I like the Wurth copper stuff.

Garth S

Yep ... that's the allan bolt. The 'nut' shown is integral with the half-moon bushing wrapped in the stainless band - so do everything possible to avoid destroying the nut .... and run a tap through it before reassembly. I had one that was seized: to avoid twisting the strap into the body of the muffler, clamp the ends of the " with "half moons" with vise grips. ( trick works on all those narrow band hose clamps under the engine as well when the screw is reluctant to start)

RallyJon

Thanks for the tip. Are my straps upside down?

993inNC

yes or if nothing else the bolt is. but if it works, whats the problem?

RallyJon

Well, I always thought that reusing a locking nut decreases its holding power. And installing bolts head down is a great way to lose a bolt.

But I won't worry about it. If it's really borked, I'll drill it out and use a new locking nut on top.

Garth S

If so, then they are upside down on my car - and were on the parts car too: if in doubt that this is correct, think of how much fun one would have cranking an allan socket from above inside the fender well BTW, the 4-5 folds in the strap work as a constant tension spring on the bolt - can't see them backing out through vibration/heat cycles.