W211 E220 '04 Rear Speed ABS Sensor Intermittent Fault ?

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pmcgsmurf

MB Enthusiast
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Location
Stirling, Scotland
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E55 AMG W211, E250 Sport W212, (and some Imps)
Hi

Anyone done any of these faults found it to be more likely to be the ABS/Speed sensor or the Impulse Ring?

Can get the Impulse Ring cheap enough (£12 Genuine Mercedes) but the ABS Speed sensor is over £100 for a genuine one. :eek:

I'm assuming to get to the Impulse Ring it's a total strip down to get the rear brakes & carrier off then the driveshaft out?

See some non OEM ABS sensors for £24 so was thinking of getting one of these to try it first to see if this clears the intermittent fault.
 
Is the wiring ok? Sometimes the abs cable/loom can get rubbed through if its not properly secured.

Id have thought so,Remove caliper, Drop the rear suspension out of the way to gain flexability of the hub, You'll need a special Star Socket i think too as the Driveshaft nut is different to the norm.
 
We have done a few recently and its always been the ring. Yes its strip down of rear brakes etc to get driveshaft out.
 
Thanks folks. :thumb:

I'm thinking of sticking it on the ramp, stripping it down and doing the rings and brakes at the same time then re-assembling it with the same ABS sensors.

Easy enough to then do these if they need it afterwards.

I'll certainly strip it all down and have a good look see to see how things are.
 
Stripped the rear suspension down today and pulled out the axle shaft.

Man, with the wheel carrier on and the spring control arm still connected (everything else off) it's a real pain to pull the carrier far enough away to get the axle shaft out.
Got there in the end but a lot of pulling and pushing, even disconnected the bottom shock bolt.

Wondering if I should just bite the bullet on the other side and remove the carrier completely first?

Impulse ring, doesn't look very good at all.
Is the rubber part meant to be connected to the metal ring or is this a separate seal and part number?

 
Got some new impulse abs sensor rings.

It does indeed look like there is some sort of plastic coating on the the ring so I assume the ones off the car have just deteriorated away?

Good opportunity to clean all the rear brake pipes up and see how these look.
May consider just replacing the pipes to the rear flexi hoses but, maybe just join under the protection covers around the middle of the car.
 
Hello, anyone following? :D

Well that made for an interesting few hours this afternoon.
Thought I'd have nothing better to do than fit the new impulse ring and put the axle shaft etc. back together.

On checking the ABS sensor this was corroded solid into the wheel carrier, see below after drilling it out, sensor gone.




Before I knew it had the entire carrier off to get in to drill out the old sensor and clean everything up.



Since I had the carrier and back plate off decided to media clean these and paint the back plate after acid etching it.






Gonna mask up the bearing tomorrow and get this cleaned up a bit then can get this side back together almost (need a sensor).

One thing I did find, there seemed to be a seal between backing plate and the wheel carrier, can't see this on EPC, anyone know?
 
One thing I did find, there seemed to be a seal between backing plate and the wheel carrier, can't see this on EPC, anyone know?

If they are anything like the front ones, then these had a ring of sponge foam attached to them so not a separate item.
 
If they are anything like the front ones, then these had a ring of sponge foam attached to them so not a separate item.

You are correct. :thumb:

Had a look at some new backplates and they have the little piece of foam attached to them.

Will cut some foam up and use a little bit of gasket seal on it too.

Got a price for the ABS sensor from MB, £112 each. :eek:

Went and got some Cambiare ones locally for £25 each.
 
Been too busy with family to get on with the car.

Cleaned up the bearing and hub though.

Also cleaned brake pipes and they should be ok once I apply some sealant and wax onto them.

Made a foam gasket up to fit between the back plate and wheel carrier and gasket sealed this in and got the wheel carrier, back plate hub back together.

Hopefully get the time to get this back on early in the week.

Only thing then is I'll need to do exactly the same to the other side once this is done.
 
Hat off to you sir for doing this yourself and so thoroughly.:thumb:

Would it not be worth replacing the rear bearings especially as you're going to all this trouble?

You might also want to book it in for a wheel alignment once it's all back together.
 
Hat off to you sir for doing this yourself and so thoroughly.:thumb:

It makes a huge difference having a lift at work, we don't do cars by profession but 3 of us at work are into cars so have a lift in the loading bay round the back.

Would it not be worth replacing the rear bearings especially as you're going to all this trouble?

I thought about that but have checked it over and I'll go with the one that I took off for now.
It's not actually too big a job just to change the bearing if it does need it in the future and I only do a few k miles pa in this one.

You might also want to book it in for a wheel alignment once it's all back together.

Have that covered with one of the local companies that has a full laser alignment setup.
 
Hope folks don't mind the odd update, may be useful for others doing similar job.

Been a bit busy to get round to doing the car but managed a couple of hours on Friday.

Got the wheel carrier, back plate, shoes and disc all back on.

35761896336_6e1010fa49_z.jpg


34992599253_b651b539b1_z.jpg


35670815001_f54142d341_z.jpg


Had a problem with the disk rubbing off the brake back plate when first put back on.
Not sure if this has been bent a bit when coming off or if it's a result of cleaning it up and painting it.

A little bit off modding with a couple of tools cleared this up quick enough.

Took the time to also clean and treat the brake pipes and the wishbone etc. with a bit of rust convertor.
 
All back together, both sides done and no faults showing.

Took the time to clean, coat and wax the brake pipes, change the diif. oil, flush the power steering fluid and do a regular oil change and service on it at the same time.

Running very nicely now.

Pity we can't see the pics. now!
 
Well done, and thanks for posting your activities.
 
Hello, anyone following? :D

Well that made for an interesting few hours this afternoon.
Thought I'd have nothing better to do than fit the new impulse ring and put the axle shaft etc. back together.

On checking the ABS sensor this was corroded solid into the wheel carrier, see below after drilling it out, sensor gone.




Before I knew it had the entire carrier off to get in to drill out the old sensor and clean everything up.



Since I had the carrier and back plate off decided to media clean these and paint the back plate after acid etching it.






Gonna mask up the bearing tomorrow and get this cleaned up a bit then can get this side back together almost (need a sensor).

One thing I did find, there seemed to be a seal between backing plate and the wheel carrier, can't see this on EPC, anyone know?
I need to replace the differential output seal on an SLK R170 due to a leak. Can the rear axle be removed from the differential without taking off the backing plate. Some people are saying clips need to be removed from the inside and others say it can just be pulled away from differential.
 
I need to replace the differential output seal on an SLK R170 due to a leak. Can the rear axle be removed from the differential without taking off the backing plate. Some people are saying clips need to be removed from the inside and others say it can just be pulled away from differential.

No idea sorry.
 

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