Hello,

I have a failed wheel speed sensor on the front right. Replacing the sensor is simple enough but I think that after 10 years the tone ring should be replaced too. Does anyone have the relevant diagrams/instructions on the tone ring replacement? I have searched the internet but can't seem to find the relevant information. I just bought the AllData subscription but doesn't seem to contain any information whatsoever.

2013 C300 4Matic

 

I have a diagram for my 2010 c300 4matic. it doesnt show the impulse ring for some reason. The diagram for the rear does show the impulse ring and part# though.






It shows it on the rear. Odd.

 

Thank you, I appreciate this.

 

The only thing I can think of is that the front pulse ring is part of the entire front axle assembly.

 

OH god, I hope not. Will find out soon!

 

Front axle assemblies are not that expensive. And not hard to replace. But, if you don't have the knowledge, skills, and tools to do it, take it to a shop.

 

Im thinking the impulse ring is part of the shaft seal. When I search for the front impulse ring for a w204 they look like shaft seals.



When I look at the diagram for the w204 rear wheel drive hub it looks like its showing that shaft seal as #40. Unfortunately it doesnt tell me the name of the part because it is not relevant to my car.

 

Thank you, this is very helpful! When I searched (on google) the part number for the "tone ring" found on rockauto it seemed to be for the rear axle shaft. So this combined with your info would also lead me to believe that there is not a separate ring for the front axles.

I think I will just replace the speed sensor and hope that solves the problem.

 

@TimC300 Your last illustration showing #40 is for a RWD C-Class, not the 4matic. My C350 is RWD and the part number for #40 is the one given by SWAG for the replacement, 204 330 00 60.



From FCP Euro.

 

Notice the Febi part number matches the last five digits of the SWAG part number. I wonder if SWAG makes the part for Febi.

 

Yes, thats the front hub for the rear wheel drive. I worded it confusingly.

 

Heres the link to the website I go on for all the parts diagrams:

https://truckmall.ru/epc.aspx?mid=10519




It should bring you to this page. This is for my 2010 C300 4matic sport. If you want to find the diagrams for your specific model , doesnt have to be a W204 can be any Mercedes, just type in a part number that you know goes to your car in the box that says "NUMBER (article)", then click on that part, scroll down and you should see all the models it fits, then click on your model and it should bring you to a page like I posted above. It will be listed by Model and then submodel. Mines a W204 and submodel 081.

Example, i typed in the part# for an exhaust clamp that I know goes to my car in that search box. Then this screen popped up:



Click on the Mercedes Part. Then this screen popped up:



Click on the link under the "Description" row. Then it took me here, which lists a ton of models it goes to. Click you model.

 

Thank you very much, Tim! This is very helpful.

 

The ring can be seen on this cv axle image from rock auto (left side).

 

Interesting. i was looking through listings on ebay at used axles and none seemed to have those included, leads me to believe they arent really stuck on there or else they would just leave them on. Fairly simple to replace if needed, but a pain to get out. When i replaced my front struts the axle just pulled right out from the inside, not sure theres enough room to fully remove it with just the strut removed or the control arms would need to be disconnected also.

Just found this diagram on an ebay listing, shows the "tone ring". Listing is just for the "CV axle" no tone ring

 

The ring looks like the one by SWAG, et al. Here's what you now need to consider. Replacing the ring is going to require some disassembly of the suspension since the steering knuckle needs to be moved far enough to allow removal of the axle. I haven't done it on a Mercedes, but did on my Audi TT a couple of times. You will need some special tools, like a ball-joint separator or pickle fork, and a wheel nut wrench. Of course you will need a jack AND jack stands. An alignment may not be necessary, but it may.

When I had to replace the wheel speed sensor on my C350, I never gave a thought to replacing the tone ring. It was not damaged and there was no need. If I were you, I'd install the wheel speed sensor and see if that fixes your problem first. If not, the only thing you need to repeat is removing the wheel. There's no real time saved by trying to do both things at the same time. It's not the same as replacing an internal water pump when you do a timing belt change on a VW/Audi.

 

Agreed, I have most of the tools but I'd rather not get involved in a lengthy repair if it is not needed. Perhaps the tone ring is bad and perhaps it will last another 50,000 kms. I will replace the sensor and report back.

 

For the price, I would replace the entire axle rather than getting a tone ring we think will fit.

 

The tone ring on this axle does not look like it would come off easily even though it shows as separate. NOTE: On second look, these pics may just be representative.

 

Yes, totally worth just replacing the axles - even though mine look like new.

 

Amazon part failed. Ordered two BREMI sensors from RockAuto - codes/problem went away. So I guess I got lucky and didn't need to mess with the tone/impulse ring replacement.

 

Some things ain’t worth going cheap.

 

It was actually not the price but the time it took to get the part - but a lesson learned about no-name brand parts.