vikingpilot

Hi,
I am going to change spark plugs, and coils. As part of the process I will remove the muffler, to get better and easier access.

My question is, can I buy just the Bolts and nuts for the left and right catalytic clamps. I believe I have to loosen both to get the muffler out.
My bolts and nuts is pretty corroded.

I see they sell the Catalytic clamps with bolts and nuts attached as a kit on Sunset Porsche.

Appreciate any input.

swingwing

Pictured is the clamp that connects left muffler to the center muffler. These bolts/nuts are corroded because of heat cycles and water exposure. I recommend you replace them. The clamps themselves were in good shape so I reused them (didn't have replacements anyway).


Fister sells the replacement bolts as a kit for $10. Also pictured here is the reversible ratchet wrench I used to get the 13mm nuts loose that hold the muffler bracket to the cat. If you take the rear bumper off you won't need this tool.

4Driver4

Seems like a lot of extra work to me. There really is quite a bit of room with mufflers in place...once you get used to it.

swingwing

"Wonder Wrench" employed on the 12 o'clock cat nut for L muffler support bracket. With rear bumper off you can use standard ratchet and socket. This nut and one at 8 o'clock are the only ones you'll need to take off to remove the mufflers. I put new copper exhaust nuts on at reassembly. The cat bolt at 4 o'clock snapped off when I went to replace that nut. I punched the stub out of the flange and fitted an M8 bolt and new copper nut.

swingwing

I wanted to change spark plugs at the same time the mufflers were out. I could not get the left upper heat shield off though, so I put the new mufflers back in and am saving plug change for another day.

dgjks6

Cut the bolts off and replace with Home Depot. Takes 15 min (second time, first time is a couple hours). Then let rust until next time

From a NEOhio 4 season driver.

swingwing

Easier said than done if you're talking about the 3 bolts on the cat flanges. They're press-fitted into the flange; even if you cut them you'll have to punch the stubs out of the flange. Couple of whacks with a good punch and hammer ejected the one that snapped on me. I subbed an M8 bolt from spares and new copper nut. If you want the Porsche parts:

900 075 365 02 (Screw, M8 x 30), qty 3 for each flange
900 910 003 03 (Hexagon nut, M8)

4Driver4

That's what I did. It took plenty of error to eject the studs. I was worried about bending the flange. I have a giant box of Audi bolts and nuts where I found the replacements.

vikingpilot

Thanks Gentlemen.....Appreciate the information.

platinum997

Why couldnt you reuse the original bolts and nuts?

jeebus31

Remove the mufflers for an easier R&R on the sparkplugs for a 997.1. It takes about 15 minutes to remove them. I used liberal amounts of PB blaster on the exhaust/cat bolts and they came off fine and went back on fine.

swingwing

platinum997

Understand..If your doing it go stainless.

McMaster is a good source.

https://www.mcmaster.com/#91287a154

dgjks6

My cat boots were corroded so cutting was the only choice. I had to use a punch to eject the studs. First one was scary. I replaced them with regular bolts and nuts. And I promised to loosen them every 6 months so it didn't happen again. Plan did not work. They are already so corroded they are going to need cut off next time. For some reason only the cat ones corroded that bad. The ones to the center muffler still look new.

swingwing

It's mostly the heat cycles in the cats. Add exposure to the road salt in winter months and presto, you're fighting accelerated corrosion. As platinum997 suggests you might try stainless bolts. I bought a pack of 25 copper plated exhaust nuts from Amazon for $11: