Help with replacing driver's side Cat on '99 ML430
 

Hello, I am in the process of replacing driver's side catalytic converter on my '99ML430. I took all the bolts out and the cat (the pipe section from exhaust manifold to the muffler) is loose, but short of disassamblying the frame, I cannot see how to get it out. Any help would be greatly appreciated, because a wife without a vehicle is a wife I wish did not have :rolleyes: And, she's a keeper, so please help if you can. Thanks!

Go to ML forum. Then go to advanced search, type in my in my screen name where it says user name and for keyword use "converter". That should take you to a few threads I did when I removed mine.

Edited:
That cracked converter business happened so much they did a recall on it. Take vehicle to dealer they should fix it for free. Mine had the problem before the recall, so I just fixed it.

Ron, thanks. I used the search function before, but for some reason did not come across your thread. Unfortunately, all the pictures have expired and I just don't know exactly what a torsion bar is. Is it the round black bar that runs logitudinally along the vehicle, engine to just before muffler? Where do I measure the lift? I don't have an air hammer and my truck is on a couple of jack stands on the drivers side. All the bolts are off the cat and it is haging loose... Have I bitten off more then I can chew?

Oh, and my truck has almost 108K mi and even though my VIN range is in the general cat replacement campaign bulletin, I did not get a PERSONAL letter, so MB will not, CATEGORICALLY, replace my cat - even though they already had replaced the passenger side cat a while back because it split down the seam due to poor workmanship. Can you tell I'm a little bitter? :(

Yes, apparently the photos only stay up for so long. As for the air hammer, I would not have been able to get it off without one, but I'm definatley not very strong.

Measure the lift thru a hole in the bottom of the torsion bar near the rear, sorry but it's been a while since I did mine and I forget exactly where. I used a venier caliper to get the depth.

I think one of my treads has the whole process outlined.

Technically the job is not hard it's just a pain. I'll look to see if I have any of the photos anywhere.

Cat
 

Hey vr430; Misery loves company. I too have a ML with a cracked driver's cat. Even though VIN is in range, dealer and MBUSA refuse to even consider replacing it. I wish I knew what the date codes on the cat need to be in order for MB to honestly believe this is not worthy of replacement like all the others who got letters.

Finally decided I need to replace it only to find none in stock at dealer and they have had one on backorder for another customer supposedly since December. No wonder everyone didn't get a letter. Could this be MB's way of controlling and managing the "free" replacements?

Anyone know of a shop in the Hartford CT area who would do the weld if I pull the cat assembly out of the car? Thanks.

Any shop that does tig welding can fix it. I recommend tig over mig because you get much better penetration with tig.

Ron, did you have to take off 3 bolts that hold the coupler - hexagonal piece of pipe to the control arm (?)?

I'm still not able to visualize how the rod comes off. I climbed under the truck yesterday and cannot see where to pound. Thanks for your help.

recall
 

hey there is a recall for the catilyst converter if you didnt know. Labor and everything is covered. Just take it in to your nearest Mercedes Dealership and they will take care of you. I had the same problem.

I don't think so. It's been a couple of years since I did this job. Unfortunatley the photos I posted in the thread about the repair are not there anymore, and I can not find them on any of my backup discs.

Post a photo of the part you have a question about and I then I can probably explain. The control arm pipe removed to the rear of vehicle. I used an air hammer to dislodge it and it came right out.

Ron, thanks. I'm not at home right now and can't snap pictures - will do when I get home. What's worse - the crack on the cat is now visible, and ML now sounds like something from a Monster Truck show, especially upon startup. And it's the poor workmanship on the weld - no doubt about it - I can peel off the weld with my finger to expose the seam!

Have you ever come across the WIS R&R procedure for either the cat or the torsion bar? I'm wondering what MB says about the whole rigamarole. I know what I see - cannot remove cat pipe without dislodging the torsion bar, - but this is ridiculous! MB engineers must have been on crack the day they designed this!

Thudux - please read mine and YuCrew's comments - this is NOT a true recall.

No.

Below is link to my adventure with this project over 2 years ago.
http://www.peachparts.com/shopforum/ml-gl-g-wagen-r-class-unimog-sprinter/92964-r-r-catalytic-converter.html?highlight=converter

Unfortunatly photo are gone and I don't have them. I've emailed moderator and asked it they can be restored.

Thanks, Ron. I've gone through that post with a fine tooth comb over the last couple of days, but pictures are worth a thousand words... Hey, I'm bigger "waffler" then you, what can I say :o

Okay - I took the adjustment bolt out. Nothing else seems to wanna come out. I cannot see where there is much room for the bar to slide backward. See picture.

I then released the bracket holding the coupler (gold colored). Do I pound on the coupler? What supposed to come off from where? See picture.

I cannot see where I can pound on the hexagonal piece. Things are just not self-evident to me - sorry.

Thanks for the help.

Do not pound on the coupler.

When I clicked on your photo it appeared on my computer in very poor quality.

Take another photo showing the area further toward the rear by about 1 or 2 feet from where you took the first photo. Take that photo looking towards the front from the rear.

I was trying to comply with the 65KB limit. I'll make next picture bigger. please note I already put the bracket back on.

Also, any hints on how to put the adjustment bolt back in? I took it all the way out.

Thanks Ron for the help!

At the very front of the bar is that hex shaped piece, I thought they were black painted. Under that hex piece is the end of the bar, there is a gap inside and then the front is the control arm, all under that hex. You can drive that hex piece back just by tapping on it with a punch and hammer, just on the edge of the hex piece. It'll side back, one the front of the hex piece is off the control arm the torsion bar is free. The original MB pics showed the hex piece with 2 set-bolts to hold it all in place, guess they decided the hex piece ain't going anywhere with all that force twisting it! Once the pressure is off, by backing out the adjusting bolt, it's safe to mess with then.
Gilly

Gilly, thanks for chiming in!

Do I tap at the front (where it goes into the coupler) or the free end of the hex piece? Do I tap from all different angles towards the back to make it loose? Is that the idea? To put it back in - do I tap it towards the coupler?

Oh, and would you give me a clue how to put the adjustment bolt back in. Thanks! Between You and Ron I KNOW I can do this!

Spray some PB Blaster or something like that where 16a and 16e go together. You might be able to pull 16a out. I could not and used an air hammer. I postioned bit with chisel end where arrow is and it popped right out.

So, looking at the diagram, I should be able to pound/pull 16b piece out and that will give me room to pound the bar out of the hexagonal sleeve - right?

Or, do I pound on the sleave and make it go out of the coupling and over the bar itself?

Sorry for the million questions.

Hey! Got 16b out! What would happen if I pound on 16d toward the back?

Also, looking at the adjustment bolt setup, I'm getting worried!

Once the loading is removed from torsion bar 16b will drop right out, then 16a is just hanging there. You do not pound on the hex sleeve, you pull on the bar if you can or pound on it (the sides of it) with a chisel. Pound it toward the rear of vehicle.

Possibly screw up something, that is not where the force needs to be applied.

When I pull on the bar, the hex sleeve moves and not the bar inside. Oh well, I'll go pound on the bar some...

Cat
 

Hey guys. I've been following your exchange with great interest since I'm about to tackle this soon. Isn't the torsion bar 16a? The sleeve 16e? Can't figure out how 16b factors into this adventure. Is the bolt you're worried about 16f of 16c?

Thanks for taking the time to document your adventure.

Welcome to the show!
Yes and Yes
If you do not remove 16b, there appears to be no room for torsion bar to move back. It can only go down and back one 16b is out of the way.
Yep, that'd be the one.
Thank Ron and Gilly - without 'em, I'd be having a cocktail right now :)

Back to task - only the sleeve is moving (back and forth), not the bar IN the sleeve, when I pul on it from the back. I tried chiseling at the arrowhead, but again, the sleeve is moving, not the bar itself. Ron, did you actually pull the bar out of the sleeve?

Believe it or not 16I is the biggest hassle of the whole job, trying to get that stupid rubber boot over the top of the hole. I always pounded the collar/hex piece back towards the rear, it can just stay on the round part of the bar until you're ready to put it together,. For adjustment you measure through the hole in the bottom bracket with the "tip" end of a vernier caliper to the bottom of the paddle of the torsion bar, this sets the height. If you didn't do this, just set it the same as the other side, you're supposed to measure and record the depth before unscrewing the adjustment screw. Putting the bolt in I guess I can't describe, doesn't present any great challenge; righty tighty lefty loosey help?
I never had to remove the "paddle" end of the torsion bar which I think is being discussed. Once the adjustment bolt is out the bottom bracket can be removed and all kind of falls apart then (except that front collar piece holding the front of the bar on).
Gilly

No not by hand, but when I hit it with air hammer it came out easily.

Hello again!

I haven't had problems with 16i yet (knock on wood) - it stayed put. I did find that it is easier to thread the bolt onto that moving target of a nut if the nut is tilted all the way towards the center of the truck. And to make sure the threads are clean of the old anti-seize compound.

As for the other end - I am getting mixed signals from Gilly and Ron. It appears to me Gilly is saying that the sleeve is supposed to come out of the coupling and slide over the torsion bar, and it appears to me, Ron is saying that torsion bar is supposed to come out of the sleeve. Which one is it? so I can target the right piece of metal. As I mentioned earlier, when I move the torsion bar around, the sleeve moves along with it - I can even pull it out an eighth of an inch out of the coupling.

And last but not least. Should I mark the sleeve and bar and coupling to make sure they all line up the same way again for the reassembly, or can they only go back in one way?

Thanks all for the extended help - ain't no way I'd be able to do this all by my lonesome!

WOW!! THAT SUCKS...I DUNNO Y THEY WOULDN'T DO THAT. I HAD NO PROBLEM RPLACING MINE. YOU SHOULD GO BACK AND NAG ABOUT IT BC I JUST RECIEVED ANOTHER LETTER FOR THE SAME RECALL AND I CALLED UP THERE AND TOLD THEM I ALREADY HAD THIS WORK DONE!

Thudux,

First, no need to shout. Second - I DID NOT get a personal letter, therefore I and all the rest of the people who didn't are screwed - regardless whether our VIN numebrs are on the tech bulletin.

I'm glad YOU got YOUR cat replaced, but just becasue YOU lucked out, does NOT mean that YOUR generalization that MBUSA will do it for everyone is correct.

I read the old thread where Gilly walked me thru this situation. From reading it I would say that the sleeve comes off with the torsion bar. Unfortunately, without the picture I don't know for sure and I don't remember. If that was the case then I put the chisel of the air hammer on the large hex sleeve and had at it. I did come right off.

I'd go with what Gilly said, I've only done the job once and I'm not a professional mechanic.

Thanks, Ron. Gilly, would you please reconfirm that I should be concentrating (pounding) strictly on the hex piece. I'll get back to it tomorrow. My SO needs the truck tonight - she doesn't drive stick...

Here is something else I found from a friend whose relative is a tech at a local MB dealer. They release the adjustment end of the torsion bar, and then one person hangs on the bar (literally!), while the other extricates the exhaust through an opening. Tech said they do that 'cause it is too much of a hassle to pull the bar out. He also said on a V8, front driveshaft may have to be dropped as well. Urgh! I hope it is only because they do not bother to take the torsion bar completely out.

I'll be sure to take plenty of pictures for posterity when I take the bar off. I also plan on writing up a DIY in all the excrutiating detail.

Thanks to all again for the help.

Yes, on the edge of the hex piece. I don't think that bar has any clearance to slide back but I could be wrong. I know I've never taken the "lever" piece at the rear of the bar off the bar itself, that stays on the bar. I do take back what I said about hammering the hex shaped tube piece all the way back until it's on the round part of the bar, you actually just hammer it back until it's back far enough to come off the hex profile piece on the rear of the control arm (just back far enough to remove the bar in other words). It shouldn't prove all that difficult to remove. When the bar is installed in the truck it's the torsional pressure that keeps the hex-tube-connector thing from going anywhere. It needs a hammer and chisel sure, and an air hammer works great, but a hammer and chisel will move it without much trouble. It MIGHT be possible to slide the bar itself back out of the hex tube, I won't argue without the truck right in front of me, look and make your own judgement, but I've always pounded the tube backwards to free it from the control arm.
Gilly

It's all over. Let the crying begin...

I'll write up a DIY later (sorry, could not take pictures), but here is what transpired last night and this morning:

Jacked up the truck. Took out the adjustment bolt and bottom plate. Fussed a little (okay, a lot) with the bar itself and then focused on the hexagonal sleeve.

Wacked the rear end of it a couple of times with a hammer and a chisel (yes, you will seriously mar the sleeve, but who cares?) and the sleeve started to slide out of the coupling and towards the rear. Yes - THE SLEEVE SLIDES OVER THE TORSION BAR. A couple more wacks and sleeve slid out of the coupling enough to expose its front edge. A couple more wacks (boy, that's a lot of wacking off - sorry, could not resist, it was a loooong night) with the chisel ON the front edge and sleeve slid all the way out and the bar came crushing down.

Think of this setup as a chinese finger puzzle - hexagonal ends of the lower control arm and the torsion bar are the fingers, and the sleeve is the puzzle itself. Once you release the tension, the puzzle slides fully over the torsion bar end and viola - it's off.

Since I do not have a lift, I could not extricate the cat out and had to drop the frame crossmember holding up the center differential. 6 bolts, no probs, except for the fact that diff slipped an inch when I took the first 2 bolts out and I had to scramble for a jack to hold it up in place. So beware, if you do not want to damage that very expensive looking piece of hardware, hold it up BEFORE attempting to take the frame crossmember off. With the crossmember out of the way, cat came right out.

With buttoned down exhaust back and secure and frame crossmember bolted on, I retired for the night expecting a major battle with the torsion bar in the morning...

Wrong! I lathered up hex parts of the bar, arm and the inside of the sleeve with lithium grease and they all came together like a champ. I used a block'o'wood to hammer the sleeve as far as it would go into the coupling and reassembled the back end of the torsion bar. Put the heat shield and the wheelwell shroud back on, dropped the truck, test drove it, cleaned and put away all the tools - all in about 1 hour!

Bottom line - if you know what to expect, have all the right tools, and do not have any problems with fit and finish of replacement parts, the entire cat replacement procedure should take no more then 2 hours. Less if you have access to a lift and air tools.

As for the old cat - I will take pictures of it and will post it all over the web, as well as send it to CEO of MBUSA and CEO of DCC, and every other possible VP of the DCC I can locate, as well as NHTSA. By the time I got the cat out, it was open like a tomato can. The weld came right off and the top separated from the body. There is no way this type of failure can be caused by anything OTHER then TRULLY CRAPPY workmanship of Mercedes' part supplier. Mercedes knows about it, acknowledges it by issuing a recall bulletin, and yet CATEGORICALLY refused to replace mine (and others) - that is just plain wrong! I'll post a picture of the cat on this thread later today.

Phew...

Pics of the Cat
 

as promissed...

You tell me - age or manufacturing defect?

Good job, Victor. It's pretty well known that a certain range of ML cats had bad welds. They're actually repairable by just re-tig-welding the bad joint from what I understand, so it may not have been necessary to buy a new one. I think I'm going to pay an indy shop to replace my cat if this happens to me given how much fun you had with it :-P

IM NOT SHOUTING DUDE U NEED TO CHILL OUT! NEXT TIME I WON'T GIVE MY INFO:cool:

When you do your entire posts in capital letters it is commonly referred to as "shouting". Lot's of people hate this. If you don't want to use the "shift" key to capitalize when appropriate, then just don't capitalize anything. I don't know if there is a name for doing that or not, maybe "mumbling"? Here's the difference, let me show you: THIS IS KNOWN AS SHOUTING. IT MAKES IT LOOK LIKE YOU ARE MAD OR UPSET, EVEN TOUGH I'M JUST TYPING ALONG LIKE BEFORE. But I'm not. See the difference? just leave the shift lock off and write like this instead, less angry people, there are enough already.
gilly

Besides, your info was not entirely correct... So it would have been better if you indeed kept it to yourself - or at least off this thread.

It's Vitaly, Ken - Vitaly :)

I do indeed plan on welding the cat back and holding it for a spare - but only after I write a nastygram to Dr. Z. Other then the failed weld, piping on the old cat looks pretty good.

And Ken, after all said and done - once you know exactly what to look out for, this job is not that hard. All you need is a jackstand for the truck, another for the center diff, an assortment of metric sockets and a chisel and a hammer. Really... Look out for the DIY - I'll write one (okay, copy and paste) for the list as well.

Gilly, should I write the DIY on this thread? What's the procedure? Thanks.

I'll link this to Bill Wood and he'll contact you either on or off list.
Gilly

...and here's the catalytic converter TSB from MBUSA which might help with your writeup, Vitaly. It was posted to Ken's list already a while back if I recall correctly. :)

http://www.whnet.com/4x4/pix/sc2005060014.pdf

Thanks Wolfgang. I searched Ken's site for references while gathering info, but did not see it then - pity, as it would have saved me serious time. Looking at the pdf, however, I do remember seeing it on the list and your site... I just never read the ENTIRE bulletin - live and learn :) Interesting that SCB recommends removing front springs and I did not have to do that.

Oops..sorry...old age :-)

BTW, I did link to Wolfgang's PDF on my Outpost site...it's under Known Problems, then ML320 Catalytic Converter. Looking forwarding to adding a copy of your DIY to my site...I suspect others will be asking about it when theirs inevitably cracks :-P