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1995 S-420
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Discussion Starter #1 (Edited)
Hi all. My 95 S 420's starter was bad so I recently got it replaced. along with the good news that I have a brand new starter, the mechanic also gave me the big bad news. The flywheel ring gears are worn and need to be replaced. Its kind of holding right now. The car starts ok but some times specially on a cold start, i can hear the gears slipping.Its going to give soon I guess. Does anyone know if the entire flywheel needs replacement or the gear ring alone can be replaced also in a situation like this?

I've been searching around on the net looking for a used one, but it seems like there are none available for 95 S420. I don't even know if flywheels from any other year or model will even work for my car or not.

I will appreciate if anyone can provide any information about this or know where to get a used one. Stealer prices are totaly out of reach for me.
I really hope that my dream of enjoying a W140 doesn't end before even starting. any help will be highly appreciated.
 

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W140 Mercedes 500 SE, 1992, European, 410.000 km
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wait wait wait. this is strange. how many miles on odometer?

hard to believe that ring gear is bad so you hear how it slips. if i were you i would check it personally. 15 minutes job. put the car on stands securely, remove plastic cover under the engine and let somebody else rotate the crankshaft into clockwise direction (when you stand in front of the car and look towards its rear end). otherwise you can damage timing chain and tensioner. or find another opinion.

You can observe teeth on ring gear if you have an assistant who will turn the engine. if not, you can turn it on your own but it will take you more time. One turn for ca 10 degrees ... one crouch under the car ... ca 30 times. mark with a pen every position on a ring gear after each turn to be sure you checked every portion on it. namely, there is an opening through which you can reach the ring gear and observe ca 10 degrees of its circumference. I hope i was clear.

I can believe that one tooth or so is missing but not that it is slipping. be careful, when mechanics see these cars, their eyes blink green in your part of the world :).
 

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1989 W124 260E Saloon. M103 lump.
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Gear teath do wear on one side as the starter motor as it hits the starter ring and engages . I would inspect it first .The new gear on the starter will marry up after a few starts . If auto you will need a torque converter . But if its a manual shift the starter gear is removed by drilling hole on the end of the teeth and chisel it till it brakes open..Re fit is by getting starter gear hot and line it up with flywheel then slip it on the flywheel with tongs or grips to seat it. What ever type of box it is means gearbox will need removing to do the job .This is how the fitted gear rings some time ago .I have done them then .The idear now might have changed, and nut and bolts could be used,
 

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1995 S-420
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Discussion Starter #4
Thank you samosali and TrevorHadlington for the replies. My car has 219000 K's around 136000 miles roughly and its an auto transmission. TrevorHadlington, are you saying that i'll need a torque converter in order to replace the flywheel? OOO my. I am screwed big time arent I?

I am taking the car to another mechanic today and will provide some updates. And most likely a lot of questions.
 

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W140 Mercedes 500 SE, 1992, European, 410.000 km
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i do not see why you should need a new torque converter.
without a doubt if the ring gear is damaged then you must remove transmission, that is clear. i did not do it so i do not know for sure but i guess you do not need to remove it completely, maybe just remove all bolts and then put it aside (and down of course on the floor ...).
but i doubt your ring gear is damaged, common, after 219.000 km? my car had 270.000 km when i bought it and ring gear is like new today.
tell the mechanic to show you the ring gear.

and please do not panic :). i think your starter is bad or something else is wrong, maybe one small stupid thing and you have impression that it is end of the world.
 

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Discussion Starter #6 (Edited)
Thanks for the encouraging words samosali. Well I just came back from the mechanic. I went to him to get the 02 sensor and camshaft sensor replaced. The car is in limp mode with the ASR light on. Replacing those 2 parts have improved the performance. Still is LH mode though which most likely is due to bad ETA. anyways while the car was on hoist, we tried to check the condition of the flywheel. It was almost not visible at all. The only place where we could see it were 2 small holes size of nickle or a quarter in the cover underneath it. The mechanic put a little paint stroke on the wheel as a marker and started moving the wheel with a screw driver. He completed the full cycle and we didn't see any wear on it. although it was barely visible through those small holes but no significant wear or damage was seen.

Now, there could be 2 different things here. 1 either the mechanic who put the starter in is a crook and lied to me about the wheel and put in a rebuilt or bad starter and charged me for a new Bosch one, or 2 the wheel does have some damage but we couldn't see it properly because of small openings. The mechanic said it doesn't look like the wheel is bad and that it looks like something else, but he didnt seemed to be sure either. I am really confused. Honestly I am loosing confidence in these mechanics. If nothing else works I am thinking of having the starting problem checked out by the MB stealer in hopes they will provide some honest info to get to the source of the problem. What do u guys think?
 

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W140 Mercedes 500 SE, 1992, European, 410.000 km
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i am not a super expert for these cars. i assume the opening where you can see the flywheel is relatively big. It is so on my M119 engine. I do not know in which details your engine is different from your engine. why didn't you take any picture?

i am not surprised that ring gear is ok. Look, this is not KIA, there is no logic to expect that ring gear will be bad. it must last 2 million kilometers if you ask me.

the real question is what is "starting problem". I am under impression that your description is simply not good enough.

P.S.: the opening enables observing ring gear exactly from below. it also enables access to it, so to block it when you work on crankcase for instance. i think you just pick up wrong openings.
 

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1995 S-420
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Discussion Starter #8
Thanks for your input samosali.
P.S.: the opening enables observing ring gear exactly from below. it also enables access to it, so to block it when you work on crankcase for instance. i think you just pick up wrong openings.
First of all, its not an opening. Its 2 holes directly underneath the gear ring which are not very big. U can hardly put a screw drive through them or ur finger. May be I am looking at the wrong opening, that was the only access underneath the gear ring. I am sorry I completely forgot to take pics. I should've. I'll try to take them tomorrow with my phone and post them.

You are right about my description not being clear enough. I think Iam going to have to make a small video of the starting process and post it online explaining what kind of sound its making.
 

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1995 S-420
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Discussion Starter #10
Thanks for the reply and the picture samosali. This area on my car looks nothing like this. I'll try taking some pictures this evening and post them when I get back home. May be its a European and the North American difference. Any one from North America who has any info about this want to chime in on this?
 

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93 SL500, 95 SL320, 96 S320, 98 S500, 2002 E320 4Matic Wagon & A little 91 5.0 FORD Mustang
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I believe in taking ownership of your car-Not saying you need to work on your car..

Buy some car ramps. Roll your car onto them. Buy your self a cheap $20 Chinese inspection camera from ebay. Nearly all those camera will take freeze frame pictures, and most of them LED illumination...

You are doing a "short colonoscopy" of maybe 10cm because you have the sub-frame cross member in the way across the access torque converter bolt hole. You may have the suspension stabilizing shock in the way too.

Tape the camera head to some kind stick/dowel/measuring ruler...

Step out of the box, and take ownership of your car...

Martin

This process may ask of you to remove the plastic cover(s) which you will need a 8mm socket with a ratchet...
 

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1995 S-420
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Discussion Starter #15 (Edited)
Thanks for all the input guys. MAVA makes total sense here. I think all the MB owners specially with an old MB should have this kinda of tools and gadgets. You never know when u need one. I am going to look online for an inspection camera and see what I can find.
 

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Because the are related
M119 should have similar opening to access torque converter bolts.
yeah, and that's (similarity) all what counts in this thread :)

Azatrum, Martin told what I wanted to tell you :). Ok, maybe you can do it in some other way instead with camera, but anyway, get yourself good stands (ramps) and go under the car :).
 

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1995 S-420
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Discussion Starter #17
Some pics of the ring gear

Ok guys. I just took some pics by jacking up the car and laying underneath. It was a tight space so pics are a little closeups. As you can see, those 2 holes are the only openings that I can see the gear ring through. I could not find any other opening. In the closeup pic the white area on the ring is actually paint put there by the mechanic as a marker. I have also made a video and am trying to upload on Youtube but seem to be having problems uploading. Its not letting me upload. Will update you guys when successfully done.
 

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Discussion Starter #18 (Edited)
While I am trying to figure out how to upload on youtube, I want to ad something. In the starting process, I sometimes hear a sound that is made when you try to turn the key while engine is running. The kind of a grind I would say. But only for a fraction of second. I just want to ask that is there a possibility that the problem could be ignition related? In one of the videos I made, i heard the same sound even before the key was turned, I think it must be at the 2nd level of the key turn position. Also, the ignition switch, if that what its called where the key goes in is loose. I mean with the key in the ignition, i can move it slightly up,down and side ways also. Can this also cause starting problems?
 

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ok, sorry i think the two holes are exactly the same as in my engine. i am an amateur and i do not work every day on this problems. never mind it is actually not important. your ring gear looks ok. no missing tooth?

in theory teeth can be too low. i will be working today on my car and i can measure the height of teeth for you. if this will be approximately same then you can close ring gear problem and concentrate in other things.

the sound you are talking about can be due to timing chain tensioner. for a short moment it can be without pressure and consequently timing chain is not stretched and you hear grinding sound. i was told it is totally normal for these cars. true, i had this sound in the past, not any more now. it is random it seems.

my ignition lock is also slightly "loose", no problems at all. In addition, the ignition key can cause no-start condition and not special sound effects.

So i guess if it is not tensioner, then it is something related to starter. but let's first check height of the teeth on a ring gear, use a proper measuring tool, i do not know its word in english :(. you can also do it in some another way with making pre-cut thin bars and compare the height of the teeth wit it. when you find a proper height you measure the bar and report it here.
 

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Discussion Starter #20
Thank you samosali for the information. I will try to measure the teeth height and report it. I will try looking up the name of the measuring tool. If I cant find it, i'll measure it some other way. So the grind sound could be the timing chain tensioner, Hummmm. Yes that grind is random and only for a fraction of a second. But beside that, there is ticking sound which I thought was the gears not catching and slipping. I should be able to upload the video today for everyone to see what I am talking about.
 
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