500E Distributor and rotor problem

[Thierry]

Moderator edit: The solution to the problem below was documented about a year after this thread was posted. Click here for details.

The problem is known. A car standing for some longer period. Start and drive...everything okay.

Turn off warm engine... 15 minutes later, moisture in the distributor.

a lot of things are spoken about this issue, but never a clear solution.

After some reading i'm going to replace Rotor, Dustcap and distributor from Beru.

I cleaned everything very carefully before attaching the new pieces.

I'll get back when i have the results after some driving time

on the pictures there is very visible the moisture in the piece....


22/1 The pieces arrived see Beru pictures. Looks good.

 

[Hakie]

Yep, same here.. (same climate) with my 400E daily driver. Especially this time of the year. I wipe the caps dry and clean the contacts. Than the problem is solved. Temporary, unless you drive the car regularly...
I have a complete set (distributor) on the shelf. Don‘t know of any solution, unfortunately.

 

[Twilling]

I would always recommend to use Bosch Parts. Big difference !

 

[195910]

I would always recommend to use Bosch Parts. Big difference !

Hi
Have you used the Bosch parts recently? as some reported bad results a few years ago.

 

[gerryvz]

I think Doduco is supposed to be the best brand, if you can find them.

 

[Twilling]

Hi
Have you used the Bosch parts recently? as some reported bad results a few years ago.

Yes, changed the parts in 2017 because of bad idle. Works perfect till now.

 

[northNH]

I had this problem exactly as described with my 420 when it came to me one year ago...

Caps (Bremi) and rotors (Beru) seemed fine; insulator (Bosch) “looked” OK as well.
Based on my distillation of all that has been discussed here, I replaced JUST the insulators, with new Bosch...

Sits most of the time with zero issues since; remainder of ignition system remains untouched.
I think there must be a lot of unnecessary money spent on caps and rotors to solve this mysterious leaking vs. exuding insulator problem.

 

[195910]

I am not sure the caps are serviceable after they are contaminated. Their readings must be checked to confirm.

 

[gsxr]

I think Doduco is supposed to be the best brand, if you can find them.

Doduco is the OE mfr for the rotors. Beru rotors are were reboxed OE/Doduco, pics are on my website. IMO, yes, these are the best rotors available. (Update - as of late 2020, Beru rotors are now reboxed Facet, details here... buy Bosch instead.)

The black insulators are made by Doduco but are NLA. Bosch (orange color) is the only available option for insulators.

Caps are available from Bosch, Beru, and Bremi. I had a defective Bosch cap out of the box which soured me on Bosch caps. Bremi was never OEM for any M119 ignition parts, which also gives me pause. I've used Beru rotors without any problems - yet. IIRC, Doduco made caps in the early 90's and Klink said they were awful, went NLA, and have probably all been replaced. I've never actually seen a Doduco M119 cap.

 

[2phast]

I am not sure the caps are serviceable after they are contaminated. Their readings must be checked to confirm.

Yes, be very careful cleaning them. I used a brass brush to remove the corrosion, figuring that brass on brass wouldn't do any damage. Well, it did. A fir the car ran fine, but after it warmed up, the plastic caps must of expanded and created a situation where the car wouldn't run till it cooled down.

I had the same issues mentioned and replacement of the insulators did fix the issue for me.

FWIW. Mercedes Bosch caps/rotors are not the same as the Generic Bosch cap/rotors. I did try the generics but had all sorts of issues, replaced them with OE Bosch which were fine till I took the brass brush to them, then went with Beru.

 

[195910]

Yes, be very careful cleaning them. I used a brass brush to remove the corrosion, figuring that brass on brass wouldn't do any damage. Well, it did. A fir the car ran fine, but after it warmed up, the plastic caps must of expanded and created a situation where the car wouldn't run till it cooled down.

I had the same issues mentioned and replacement of the insulators did fix the issue for me.

FWIW. Mercedes Bosch caps/rotors are not the same as the Generic Bosch cap/rotors. I did try the generics but had all sorts of issues, replaced them with OE Bosch which were fine till I took the brass brush to them, then went with Beru.

Thanks for the update, I sense this being the case in the Beru distributor caps I have fitted in 2018. I had to clean them several times due to the previous contamination issue, But now one pin has a higher resistance only when warm which is strange.

 

[2phast]

Thanks for the update, I sense this being the case in the Beru distributor caps I have fitted in 2018. I had to clean them several times due to the previous contamination issue, But now one pin has a higher resistance only when warm which is strange.

Not really. For them to function correctly, they have a gap range, minimum to maximum, if you exceed the maximum gap range, they fail to function correctly and your car will stall. So if you remove material from the contacts but gap is within range, your car will start and run fine but once the caps get hot, the plastic expands, increasing the gap past its maximum range, then the car stalls. If you let the car sit and the caps cool down, the plastic shrinks and the gap it again within its range, the car will start.

This is the best explanation I can come up with, given no one else at the time had run into this problem, or at least no one else reported a similar issue due to cleaning of the contacts with a wire brush.

 

[gsxr]

In other threads, Klink has recommended *not* cleaning the brass contacts inside the cap. IIRC he mentioned that the voltages involved (>20kV) will blow right past any green corrosion you may see. The bigger issue is liquid inside, or on the rear surface of the insulators.

 

[2phast]

In other threads, Klink has recommended *not* cleaning the brass contacts inside the cap. IIRC he mentioned that the voltages involved (>20kV) will blow right past any green corrosion you may see. The bigger issue is liquid inside, or on the rear surface of the insulators.

Not quite the same though, "not recommending cleaning due to voltage going past the corrosion" isn't the same as saying "don't clean them, you run the risk of removing material and increasing contact gap and when the caps heat up and the plastic expands, your car will stall and leave you stranded"

 

[195910]

Gentlemen I think this is similar to the spark plug gaping issue. Yes the +20KV will go through, but If the gap is wider or the terminal has carbon buildup there will be more resistance and higher voltage requirement, which will effect the combustion characteristics.

 

[Berglund]

Hi
Someone have the Bosch part number at the distributor and rotors to the M119?
Best regards Niklas

 

[195910]

Hi
Someone have the Bosch part number at the distributor and rotors to the M119?
Best regards Niklas

BOSCH: 1 235 522 430

Try to buy the latest production date you can find

 

[Berglund]

This parts was not very “cheep”
For new rotors and distributor,
will cost about 865USD in the local MB dealer here in Gothenburg
Better price somewhere else?

 

[195910]

This parts was not very “cheep”
For new rotors and distributor,
will cost about 865USD in the local MB dealer here in Gothenburg
Better price somewhere else?

How much in Euro? do you need OE or Bosch?

 

[Berglund]

It will be around 765Euro
Bosch is what I like to get

 

[gsxr]

Beru rotors are reboxed OE Doduco. Buy those if you can find them.

Photos here: Index of /images/M119/EZL/caps+rotors

Last I heard, OE/Genuine caps from the dealer are visually identical to aftermarket Bosch. So there may not be any advantage to paying extra for the same Bosch part. I personally prefer Beru caps, after I had a Bosch cap defective new out of the box...

 

[195910]

It will be around 765Euro
Bosch is what I like to get

Bosch caps around 70-72 euros each, distributors are ~35 euros for bosch or beru.

 

[Berglund]

Do you think Bosch is produced by Beru?

 

[195910]

Do you think Bosch is produced by Beru?

No it was a typing error. For the rotors its Bosch or Beru (Deduco)

 

[Berglund]

Okay,
When I read about this parts, distributor and rotor, it seams that Bosch is the most recommended parts

 

[gsxr]

There is a LOT of debate on which brand is best. Seems different people have had problems with each brand, and recommend anything else except what failed for them personally. I already mentioned which I prefer.

I can tell you that the insulators are *only* available from Bosch, so you have no choice there. And, Bremi was never an OEM for any M119 ignition components. Factory M119 distributor ignition components were a mix of Bosch, Beru, and Docuco.

 

[195910]

There is a LOT of debate on which brand is best. Seems different people have had problems with each brand, and recommend anything else except what failed for them personally. I already mentioned which I prefer.

I can tell you that the insulators are *only* available from Bosch, so you have no choice there. And, Bremi was never an OEM for any M119 ignition components. Factory M119 distributor ignition components were a mix of Bosch, Beru, and Docuco.

I will be reporting my last findings on this probably this weekend, We all agree on the Bosch insulators, no bremi, beru wires (or OE). as well as Beru/DD rotors being the OE ones. But I am debating the Caps which have a different design for all 3 manufacturers. Bosch being the OE but not sure if its exactly the same as an M-B Boxed part.

 

[Klink]

In other threads, Klink has recommended *not* cleaning the brass contacts inside the cap. IIRC he mentioned that the voltages involved (>20kV) will blow right past any green corrosion you may see. The bigger issue is liquid inside, or on the rear surface of the insulators.

I’ll stand by that. DON’T scrape, sand, whatever to clean the metallic bits. It is absolutely unnecessary. It accomplishes nothing.

 

[nocfn]

HE'S alive HE'S ALIVE!!

 

[gsxr]

... I am debating the Caps which have a different design for all 3 manufacturers. Bosch being the OE but not sure if its exactly the same as an M-B Boxed part.

Allegedly, years ago the OE caps were slightly different, possibly coated with a high-voltage clearcoat of some sort (discussed previously on the forum). But I thought there more recent reports that the OE caps no longer were coated, and appeared essentially identical to the aftermarket Bosch caps. Of course, the one thing different will be the OE caps have the Star logo and MB part number, while the aftermarket ones have this space blank.

BTW, I think the full wire set is NLA from MB now? Pretty sure you can only get bulk wire and fittings from the dealer, to make them yourself... and only with the orange plastic Bosch plug boots. Nicest wire set I know of still available is discussed in this thread.

 

[195910]

Allegedly, years ago the OE caps were slightly different, possibly coated with a high-voltage clearcoat of some sort (discussed previously on the forum). But I thought there more recent reports that the OE caps no longer were coated, and appeared essentially identical to the aftermarket Bosch caps. Of course, the one thing different will be the OE caps have the Star logo and MB part number, while the aftermarket ones have this space blank.

BTW, I think the full wire set is NLA from MB now? Pretty sure you can only get bulk wire and fittings from the dealer, to make them yourself... and only with the orange plastic Bosch plug boots. Nicest wire set I know of still available is discussed in this thread.

Last OE set I have seen did not have clear coat. Late 201x production but can't remember when.

Yes the complete wiring set are NLA, but all the components are still available. I had a set made by the dealership last year.

I am evalueating whither caps that have been contaminated/sanded/cleaned with chemicals multiple times have deteriorated performance. And if one design (Bosch vs Beru) is more robust in that sense.

 

[gsxr]

It appears the Beru caps may have the clear coat, if so, I'd consider that a plus over the Bosch caps without it.

 

[195910]

It appears the Beru caps may have the clear coat, if so, I'd consider that a plus over the Bosch caps without it.

Yes the 2017 production Beru caps do have a smooth shiny "coated" surface unlike the matt plastic of the Bosch caps. But the molding quality is rather questionable. The plastic coating around of terminals is falling apart :\

 

[gsxr]

Yes the 2017 production Beru caps do have a smooth shiny "coated" surface unlike the matt plastic of the Bosch caps. But the molding quality is rather questionable. The plastic coating around of terminals is falling apart :\

If that's the only issue we can find, I can live with that!

 

[Berglund]

I find the Bosch distributor and rotors from a dealer on eBay in GB, around 220usd for the pair’s.
The bracket behind the rotors seams only be available in the MB dealer, will now order them, around 120usd for the pair
/Niklas

 

[gsxr]

You should not need the bracket behind the rotor, unless you have a very early build car, AND the bracets have never been replaced in the past. Check them before ordering! Otherwise you may end up with $120 of the same brackets already on the car.

 

[Berglund]

Okay
How do I now the different?
Is it any part number on the bracket?
Or, how could I now what kind I have?

 

[gsxr]

The bracket on the left is the updated type:

 

[Berglund]

Thanks for the pictures!
Getting out to the garage and check this up First thing tomorrow!

 

[Berglund]

Then may car already has the updated bracket for the rotors....

 

[195910]

Then may car already has the updated bracket for the rotors....

Those dust caps are a complete mess, it looks like mold is growing there

 

[Berglund]

Hi, some dirt it will be, the o-ring seal is old and hard, I have now clean it out, new seals will be ordered,
Do you think I must have new caps???

 

[195910]

Hi, some dirt it will be, the o-ring seal is old and hard, I have now clean it out, new seals will be ordered,
Do you think I must have new caps???

Too dirty IMO, but if you must use the old ones you need to clean, heat and re-clean them multiple times.

 

[TerryA]

I’ll stand by that. DON’T scrape, sand, whatever to clean the metallic bits. It is absolutely unnecessary. It accomplishes nothing.

Hi Klink,

Don’t stay away so long.

Your conversation, advice/input is missed and alway welcome!!

lol

 

[195910]

Hello Gentlemen,

I just bought 1 Bosch distributor Cap of a 10/2018 production for testing. @Berglund please post pictures of the distributor cap you bought for comparison. As this one I received look a little strange

 

[Berglund]

Hi,
I will take pictures when they have arrived.
Probably in the end of this week, I hope.
From where did your caps arrive?
Bought it from a local dealer or on web shop?
Regards
Berglund

 

[gsxr]

See post #21 above for my photos of Bosch & Beru caps.

 

[195910]

Hi,
I will take pictures when they have arrived.
Probably in the end of this week, I hope.
From where did your caps arrive?
Bought it from a local dealer or on web shop?
Regards
Berglund

Bought from major online vendor, pm me if you need details

 

[195910]

See post #21 above for my photos of Bosch & Beru caps.

Hi dave,

I just did, the 2011 Bosch caps on your site look the same from the wires terminal, but the internal contact points are different.
The new ones have a machined (ridged surface) rather than a smooth shine one. You can also see the ridges on the plastic encasing.
Also, the central terminal is 1-2mm longer.
The surface is not coated nor smooth like the Beru, it has a matt plastic finish.

 

[Berglund]

Just get the price from the
MB-dealer on the caps behind the rotors......
Just around 200usd/each...
I can clean it out for a several time and save “a few dollars” $$$$$$$
/Berglund