R129 replacement catalytic converter.

[SLBrighton]

Hi everyone,

My 97 SL500 has had a rattly cat for a couple of years, more so when cold of course. I'm not even sure which one is rattling, as they are both close to each other.

Can anyone recommend a good replacement? I know the Mercedes parts are no longer available and too expensive if they were. SL Shop supplies replacements at around £316 a side, but they said that they of course don't match the original quality. Maybe this is the best option? I've seen that a few people recommend getting an exhaust shop to make up a piece or fit Magnaflow etc.

I'm based down in E Sussex, but happy to travel to get a good quality part fitted.

If anyone has any thoughts it would be great to hear.

Thanks

 

[DrNick]

I replaced with BM Catalysts. I just used the bog standard ones but I think you can get them made with different flow rates for extra free flowing if you ask them. I cant speak for quality (they weren't expensive) but they have done the job so far! (Both mine went within a few months so consider getting them both done)

Manufacturer of Catalysts, DPFs & Front Pipes

BM Catalysts is the largest independent manufacturer of high-quality aftermarket catalytic converters, DPFs and front pipes in Europe.

www.bmcatalysts.co.uk

 

[BTB 500]

Are you 100% sure it's the cat, and not a loose heatshield or something?

I had a 200 cell sports cats fitted by Longlife eight years ago ... cost was £475 and they've been fine so far!

 

[SLBrighton]

Are you 100% sure it's the cat, and not a loose heatshield or something?

I had a 200 cell sports cats fitted by Longlife eight years ago ... cost was £475 and they've been fine so far!

Hi, yes, I've been told it's the cat. I might pop to an exhaust specialist and see what they say. I've put up with a rattle for a couple of years so I may wait it out! I'll see who sells Longlife around Sussex/ Kent. Thanks

 

[SpikyMikey]

Longlife in Sussex I think is still Berwick Service Station near Hailsham. A good little garage actually and usually have at least one or two interesting vehicles in for work/restoration.

 

[SpikyMikey]

Here you go:
Stainless Steel Exhausts service in Berwick, Polegate from Berwick Service Station - 01323 870598

 

[SLBrighton]

Longlife in Sussex I think is still Berwick Service Station near Hailsham. A good little garage actually and usually have at least one or two interesting vehicles in for work/restoration.

Thanks for the info about the garage. I've just emailed them.

 

[SpikyMikey]

Thanks for the info about the garage. I've just emailed them.

I'm not sure how hot they are on email. If you don't get a response, I've got my S204 booked in with them on Friday of this week; I'm happy to ask the question for you when I'm there.

 

[SLBrighton]

I'm not sure how hot they are on email. If you don't get a response, I've got my S204 booked in with them on Friday of this week; I'm happy to ask the question for you when I'm there.

They just got back to me and say they have Longlife Sports Cats in stock. I may pop over to see them and let them take a look. Thanks for your help. I wonder how much knowledge they have about R129s for servicing too?

 

[SLBrighton]

Are you 100% sure it's the cat, and not a loose heatshield or something?

I had a 200 cell sports cats fitted by Longlife eight years ago ... cost was £475 and they've been fine so far!

I'll see what the local Longlife supplier can do. Is you car a '97 or '98? Mine's a '97 and I think it just has the two smaller cats that sit close to each other in the centre. Did you get both replaced at the same time?

 

[SpikyMikey]

They just got back to me and say they have Longlife Sports Cats in stock. I may pop over to see them and let them take a look. Thanks for your help. I wonder how much knowledge they have about R129s for servicing too?

No problem. They are not MB specialists by any means, but a proper 'old school' garage. I've used them for a number of years.

 

[BTB 500]

I'll see what the local Longlife supplier can do. Is you car a '97 or '98? Mine's a '97 and I think it just has the two smaller cats that sit close to each other in the centre. Did you get both replaced at the same time?

Mine's a '97, and yes it just had two smallish cats in front of the centre muffler (which I had removed - it was dropped in the '99 facelift anyway). For some reason the new cats were mounted towards the rear of the car ... don't know why but it all works OK and passes a main dealer MOT every year! I'd previously managed to find an R129 AMG back box in Germany and got Longlife to fit that.

 

[BRN9121]

Sorry to revive an old thread, but my 1999 R129 M113 had all it's cats gutted due to deterioration and rattling.
The secondary pair are not the problem. Those can usually be replaced with universal ones or even straight-piped if your country's MOT laws are not that strict.

However, my problem is the primary cats. Those are the ones that are immediately after the exhaust manifolds. I can't seem to find replacements. I need to replace them as my check engine light is on and the fumes are horrible.

 

[DrNick]

Got mine from BMI as per the second post in this thread (1999 M113). As I recall, it bolted to the manifold. Available on ebay (new!)

 

[jasmine]

had BM cats fitted to my 97 sl500. from my experience they are a very poor fit . touched the body in a few places and pushed the back box out of line . garage had three goes at fixing with no joy. money back and stainless system fitted

 

[ray_hennig]

It's probably too late in the day for a result but I did a Google search for a cat for my 300 and found one in Germany. This was some time in 2018. It was shipped to me in France and the total price was 500€. That against the MB list price of around 2300€ plus shipment.

That was very lucky but you might give it a try.

RayH

 

[BTB 500]

I got an AMG 'accessory' back box for my R129 from Germany for a fraction of the MB UK list price, but it's more difficult to do this sort of thing now post-Brexit.

I had aftermarket 200 cell 'sports' cats fitted to my R129 nine years ago and they've been absolutely fine, including a main dealer MOT every year. They were done by an exhaust specialist (Longlife) who also fitted the AMG back box and replaced the centre muffler (resonator) with a stainless steel pipe section. The overall change in exhaust note & volume was pretty mild - most of the silencing is done by the back box. It's still basically silent when cruising (no drone etc.). And looks completely stock apart from the period correct chromed AMG tailpipes.

 

[BRN9121]

Got mine from BMI as per the second post in this thread (1999 M113). As I recall, it bolted to the manifold. Available on ebay (new!)

Was it the complete pipe all the way and including the secondary cats? Like this image?
I contacted the seller to see if what they are selling is exactly what they're portraying in the picture.

 

[DrNick]

Yep. The whole thing. I've still got the original that came off in the garage. It fitted ok but did require a bit of adjusting, according to the fitter, but not too bad.
You can ask BM to install "sports" catalysts if you want - they can fit different cores, according to their web page. Give them a ring or email to see what your options are. Might cost a bit more but if you've got one of these cars you are probably not on much of a budget.
If you are worried about fit, as Jasmine reported above, then a custom SS is an option, but you'd need to talk to a local exhaust specialist.

 

[BRN9121]

Thanks
I am waiting for confirmation from them. I need the complete pipe. All 4 of my cats are empty now and I need to go back to as close to stock as possible. Not interested in performance really.