Part numbers for exhaust system bolts

[gsxr]

The bolts of the exhaust system are usually seized up after 15-20 years, and even if you can remove them without breakage, they will likely be in poor condition. Fortunately, new bolts are easy to obtain at your local MB dealership (or, local metric hardware supply) and they are not expensive. See list and photo below. The bolts to the exhaust manifold are the only ones which can generally be re-used; apply anti-seize to the threads before re-installing. The rest are usually rusted out, even in dry southern/western climates:

Prices shown are MBNA list price as of Nov-2014:

000-990-32-50 - Nuts for exhaust system bolts, copper clad (M12 x 1.25) - $3.70
129-990-04-10 - 500E exhaust bolts, front pipe to exhaust manifold - $3.50
000931-008244 - 500E exhaust bolts, crossover pipe to main pipe (M8 x 1.25 x 45mm) - $2.00
304017-008053 - 500E exhaust bolts, cats to resonator (M8 x 1.25 x 60mm) - $2.50
304017-008028 - 500E exhaust bolts, cats to resonator (M8 x 1.25 x 50mm) - $2.40
304017-008018 - 500E exhaust bolts at muffler (M8 x 1.25 x 35mm) - $2.40
000-990-25-52 - 500E exhaust manifold copper nut, pressed in (not shown in photo) - $8.50​

Exhaust system gaskets/seals - also not shown in photo:

202-492-02-81 - 500E exhaust system seal ring, crossover pipe to main pipe - $9.50
202-492-02-81 - 500E exhaust system seal ring, main pipe to resonator - $9.50
126-997-00-41 - 500E exhaust system seal ring, main pipe to resonator (flat graphite ring) - $6.75
129-492-01-80 - 500E exhaust system gasket at muffler - $10.50​

The copper-clad nuts are available via aftermarket sources (i.e., AutohausAZ, BuyMBParts, etc) for approx $0.40/each, a substantial savings over the dealer pricing.

 

[gerryvz]

It's generally a good idea when needed, to just replace all bolts and hardware having to do with the exhaust system, particularly if it's more than 5 years old. Just gets too rusted out and hard to deal with to be worth it. Also, many times when you buy kits (such as clamps, etc.) the appropriate hardware will come with the kit.

When I did my 560SEC top-end rebuild, same thing -- you can re-use the four bottom exhaust manifold studs that screw into the heads (the tops of the manifolds are held on by bolts). However, all copper-clad nuts that go onto exhaust manifold studs or bolts (or exhaust clamps, etc.) SHOULD MUST be replaced - they are a one-time-use-only item. Pays to buy a few extras and agree it's an item that is safe to buy on the aftermarket.

Cheers,
Gerry

 

[jano]

One of the most annoying things is not having the right hardware on hand, so either you have to plan in advance for the minutia (irritating!), or stop what you are doing and go searching. I wish there were like a "box" one could buy that would have a nice mix of the most common bolts, screws, washers, etc. for our cars, so we wouldn't have to dig for part numbers and order just a few then have the parts.com ship the four bolts I just ordered in this giant fed ex box (the dealers aren't always stocked). I had been doing some non-car related DIY projects, and picked up a few variety boxes of bolts, screws, washers, etc, spent maybe $30, and couldn't be happier as I've got everything on hand.

 

[gsxr]

I keep an insane amount of miscellaneous hardware on the shelf, built up over many years. I've got one plastic organizer (similar to this) with rubber O-ring seals, another with copper/aluminum crush washers, one for M6 bolts, one for M8, one for sheet metal screws & clips, several for electrical pin bushings & housings, several for misc hardware... you get the idea. Think I have like 15 total, plus several small boxes of other stuff. Problem is, to buy an assortment all at once would cost several hundred dollars. Not really worth it for one car, maybe two, definitely for 3+ (of the same/similar chassis). I need to try and find a good deal on some used Vidmars, lol...

 

[gerryvz]

Also pays to save and (where possible) re-use hardware from things you take off your car. If you wrench Benzes long enough, you can build up a good collection of hardware just doing that.

 

[Zuffenhausen]

what are the required bolts and hardware for this pipe?

 

[500AMM]

.
Here is some screenshots from the EPC on all exhaust parts from the cyl.head to the exhaust tip.

 

[sheward]

Can anyone tell me if the seal ring 202 492 02 81 (crossover pipe to main pipe) is the same seal ring as used between the exhaust manifold and crossover pipe please? The flanges on the crossover pipe look very similar but not exactly the same.

drew

 

[gsxr]

Drew, there is no seal at the exhaust manifold... the manifolds attach directly to the downpipes.

Having messed with this stuff several times after the post back in 2012, here's another tip: For the slip-fit pipes at the catalyst exist, with the graphite ring seal... the new seal should slide into the recess on the resonator with minimal effort, and zero distortion of the seal. If not, use a round wire brush on a drill to clean out the recess. ALSO, use the wire brush to clean out the inside of the resonator pipe. When it's all clean, coat the inside with anti-seize, Repeat the process on the catalyst side, except on the outside of the pipe.

With the catalyst + resonator laying on the floor, the pieces should slide together with zero resistance - check before installing the new graphite seal, if it's "all good", then pop the seal in place and double-check that it's still a smooth fit with the graphite seal. If so, you're ready to install on the car. The anti-seize should help if you ever need to take it apart again; this particular joint is often welded together by rust after 10-20 years.

Don't over-torque the bolts, they need to be snug, but not crazy tight. If installing a complete exhaust system, get all the bolts barely snug, but still allowing movement. After getting the ENTIRE system in place, wiggle it around and make sure all pieces are aligned/seated/etc, THEN tighten the bolts. Remember to make sure the exhaust tips are level at the bumper.

 

[sheward]

Ahhh, I now recall seeing pictures of the manifolds with the cast radius shape. I'll be mounting the Leistung system from the cats back so my biggest worry should be getting things apart. I can't recall if I'll be dealing with the graphite seal after the cats and into the resonator replacement piece. Thank you for the tips!

drew