Tomorrow morning I hope to get up early and go to work to repace the flex coupling which joins the two parts of the exhaust manifold together. I bought the coupling, inner pipe, and the exhaust manifold gasket. I've heard it mentioned to replace the nuts and studs but 4 nuts would have cost me $54 at the dealer! And this is 20% less than the list price! So, I didn't buy those nuts. I saw they have automotive studs at the hardware store and I could get nuts there but would I want stainless nuts or what? Are the studs anything special? I only plan to remove the front portion so there is less of a chance of breaking something.

I forgot to buy a cross-over gasket. Could I re-use the one that's on there now? I just removed the cross-ver 2 weeks ago so I could get to more of the fuel line clips and I replaced the gasket then? (that's a gasket I usually have an extra on hand since so much work requires removing the cross-over).

Anyone have any other advice for me? I guess if the car were down it would be ok as I was planning in taking the car up there Monday and taking all the wheel off to have the rims/tires seperated tehn blasted. I was expecting the car to be down about a week or so. (bummer).

Thanks
David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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I haven't replaced the front pipe on an MB but I have on other cars (I used to work at Midas...hey, I didn't say I was proud of it ), and those studs and nuts can be a pain. Spray them liberally with PB Blaster or equivalent a few times, preferably beginning the day before you try to remove them. In extreme cases I've had to heat them with an acetylene (sp?) torch to get them to break. If you have access to an impact gun that will help. Hit it with short bursts of about half a second or a second each, and this will minimize the chances of snapping one of those studs. If you do break one, I'd look for one from a donor car before trusting studs from the hardware store. Good luck!

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1982 300D, black w/ palomino leather, 203K
2001 E320, champagne, 105K (Mom's)
1999 Dodge Dakota, squeaky & battered, 142K

I don't know what kind of nuts Mercedes uses but other German cars I have seen used steel nuts with a stainless insert Helicoil style, or brass nuts. Stainless steel nuts would be ideal, brass would be good, ordianry steel nuts will do just as well except they will rust. Use some anti sieze when you put the nuts back on and if they are common steel, don't plan on taking them back off without a torch once they have been on there a few months.

Wire brush the crud and rust off the stud and heat the nut red with a welding torch if you want it to come off easy. This was standard practice when I worked in a muffler shop. Or cut the nut off with a torch if you have a steady enough hand and are experienced with a torch. In the case of nuts and bolts I just cut them out and put in new ones.

Penetrating oil won't do any good until you break the nut loose. Then give it a shot of ordinary oil and it will come off easier.

I used to keep a plastic spray bottle of water handy to douse fires while doing this.

Good luck. Exhaust work is one of the things I would rather pay someone to do because it's such nasty work.

David,

Two members recently did this job. The odds seem to be pretty good that you will break one of the studs off in the head.

Plan a lot of time and a lot of patience. If one of them breaks in the head, you have a real serious problem.

Check out some recent threads on it. One of the fellows managed to get the stud out using a fairly sophisticated setup.

Here are the threads:

arrrgh.

SDL exhaust manifold gasket help

Broke a exhaust stud