Identifying bad caps & rotors

[gerryvz]

Here's an example of a set of caps and rotors that I replaced about five years back. You can see the corrosion and carbon tracking in the caps, erosion of the cap contact surfaces,, and material eaten away from the contact surface of the rotors.

This should serve as a reference guide. Symptoms of this would include severe missing and rough running, particularly when the engine is warm.

Cheers
Gerry

 

[Aki]

Any pics from new parts?
How much metal is new rotors and caps?

My rotors and caps are 4 years old. About 30tkm and caps are clean inside like new, but metal is gone. Rotors are worn too.

 

[gerryvz]

Your caps look OK -- did you clean the inside of them or did they come off like that? Look great!

The rotors look like they could use replacement, however. I think it's advisable to replace caps and rotors together; however, looks to me like you have many more kms available for yours.

Cheers,
Gerry

 

[Aki]

Yes, I clean them little.
Cheap set on ebay:

 

[Aki]

Here some pics from new parts :arrow:

 

[highway41]

This is getting real old; the E has started that same old skipping/missing again and I replaced the rotors/caps only a year ago. Around town mileage is not kind to these parts.
Is there anything I can do to make caps and rotors last longer? Like a way to keep the condensation out?
Thanks. Bill

 

[gerryvz]

Only think I can think of is just to run them. Man, I look at the photos of mine from Oregon, and the new ones....I am absolutely surprised that my car ran as good as it did!

Have you confirmed by taking a peek that the caps and rotors are indeed the problem again so soon? I think even mine in the Northwest went for about two years between changings. No issues here in Texas so far (it's been about 14 months) but I haven't removed them to check. I do have to say that overall, the car seems to prefer the climate here to that in Oregon though -- even the hot summer days. Now that it's cooled down to the mid/high 70s to low 80s with normal levels of humidity, it's really running nicely.

Cheers,
Gerry

 

[gsxr]

If they are not ancient, and are not pitted, simply clean them up (carefully) with a wire brush and a rag to wipe out any residue. These are not precision items... if the contacts aren't burned or fried, all they need is cleaning.

 

[gerryvz]

Well, wiping down is fine if things aren't too worn from use. However, the caps can get carbon trails in them, which perhaps can be cleaned.

But if the rotor contact surface, or the contact surfaces inside the caps are pitted or eaten away to a significant degree ... it's time to replace them.

Cheers,
Gerry

 

[Aki]

Did anyone know rotor caps seal part numbers? I was replacing my rotors and caps when I found out that seals are worn.

 

[gsxr]

The orange seal ring is p/n 020-997-05-48, list price a bit under $4 USD each.

 

[Aki]

Thanks!

 

[500ESpain]

Yes, I clean them little.
Cheap set on ebay:

Aki, are those Bosch parts you show the ones you get with that cheap set you mention??

What do you think about these:

http://cgi.ebay.com/ebaymotors/MERCEDES ... ccessories


http://cgi.ebay.com/ebaymotors/Mercedes ... ccessories

 

[Aki]

No, I bought here in Finland my local MB dealer.

 

[gerryvz]

These parts can be sourced on the aftermarket for much cheaper than from dealer sources.

Distributor caps:
119 158 01 02
119 158 02 02
119 158 03 02
$69.00 from a source like AutohausAZ.com
$76.23 from a source like buymbparts.biz (BIMBY)
$96.60 for factory MB part from parts.com
List for factory MB part MUCH higher - ~$140

Rotors:
119 158 03 31
119 158 01 31
119 158 02 31
$27.63 from a source like AutohausAZ.com
$30.53 from a source like buymbparts.biz (BIMBY)
$52.33 for factory MB part from parts.com
List for factory MB part MUCH higher - ~$76.00

Remember that TWO caps and rotors are required for the E500E application.

Cheers,
Gerry

 

[500ESpain]

Thanks for the info, Aki & Gerry!

 

[highway41]

Still missing when cold so I've ordered new caps and rotors. Gonna trust to luck that my shade tree skills are sufficient.

 

[gerryvz]

It's a pretty easy job to do, even under the shade of your local friendly cypress tree....

Cheers,
Gerry

 

[highway41]

Guess Rotors and caps are going to be part of regular maintenance.
Replaced them and the miss at idle and on acceleration when cold is gone. The old caps and rotors did not look bad; no visable tracing on the plastic and the contacts were lightly corroded. Having it run well again reminds me of why I've sat in the same seat for 16 years. Bill

 

[gerryvz]

I've done them twice in 7 years and 45,000 miles I've had my car. Seems that cap/rotors and front brake rotors are a regular maintenance item on our beasties ...

Cheers,
Gerry

 

[2phast]

Another common problem is the passenger side needing replacement before the drivers side. Seen this on E420's, E500's and 500SL's. While doing my timing chain I checked my caps/rotors and sure enough, the passenger side needed replacement.

 

[gerryvz]

Sort of like how M117 engines seem to like to eat passenger-side cams and rocker arms .... well-documented.

Cheers,
Gerry

 

[cossie]

Just replaced my distributor caps and rotors over the weekend. For the rotor I purchased part# 119 128 02 31 but I didn't bother to check the rotor bracket part# since I used the old one.

Anyway, I came across various on-line sellers who gave out warnings such as...


Warning!!!: This distributor rotor #119 128 03 31 requires the new bracket # 119 158 06 40; Rotor will break or catch FIRE if used w/ old bracket # 119 158 04 40


What is the difference between both brackets? Mine bolted up easily... just want to make sure I have the right rotor/bracket combination... I don't want my car to catch fire (in case this is true).

 

[Juho]

What is the difference between both brackets?

These pics show the differences.


Juho

 

[cossie]

Looks very similar except that the other one has a flat surface... so how can these cause the rotor to break or cause fire as mentioned.

If my rotor is the Bosch 119 128 02 31 then which bracket should I use? the 06 40 or the 04 40?

 

[Paul64]

After reading this thread, I bit the bullet (yet again!) and ordered up a pair of electric shields and o-rings this afternoon - €80+tax-10% over here for the shields.
I've had a bit of hesitation, intermittently, for few years now and although my caps / rotors are changed every year, I never thought to change out the covers.

Thanks to the forum of knowledge, yet again!

Paul

 

[Paul64]

I changed out the old rotor shields last night and was going to start up for a test drive but, I'd left the car too long with the alarm activated and the battery is now on charge... bummer!

Anyway, both the undersides of the electrical shields that were on the car had had been sprayed with an aerosol wax product prior to installation - a bit like Waxoyl for example.
Prior to me starting the maintenance when I got it, the car was serviced by Mercedes main dealers.
Is this a 'trick of the trade' we should know about to extend their life?
There were three carbon tracks about a quarter inch long on one of the shields that had formed on the surface of the wax which I wiped clean and although there is some fading of the shiny surface finish of the insulator, both old items look like they can be kept for emergency use again the garage....
Over here in France, the cost per item was €86+20% tax - getting a tad expensive methinks! New dizzy cap seals were €2.67 each.

Looking forward to super-smooth idling again at the weekend.....

Paul

 

[Paul64]

Like silk....... no more hesitation, first time in ages I have a super smooth idle now.

Paul

 

[pesuazo]

In you opinion, which solved the problem?

The seal or the isolator around the rotor?

I am still having a misfire/rough idle after new wires, distributor cap, rotors and sparkplugs.

 

[Paul64]

The isolator for sure - there was indeed the tracking marking on the back of the item.
They are €80 each here but probably a bit cheaper in the UK at the moment with the exchange rate.

Regards

Paul

 

[pesuazo]

That is the one around the rotor, correct?

Need to remove the rotor and bracket?

Thanks

 

[gsxr]

That is correct.

 

[bing]

in the UK they are £78each plus 20%tax from MB. part#MA119 158 01 88 not cheap
and they come with the rubber seal ring

 

[pesuazo]

Just went to the dealer. 119 for the isolator and 4.50 for the seal.
I noticed my car did not have the seals. Just ordered those (9.00) to see if issue goes away, if not, then I will dish out the other US 240 for the 2 isolators

Thanks for your responses and help

Update:

Just got a quote from Peachparts.com; 89.00 each with free shipping (guess whom I will be ordering from if needed?)

 

[gerryvz]

$81.65 each + shipping at parts.com. I would think it would be about the same or slightly bertter than peachparts price, particularly for two of them.

Cheers,
Gerry

 

[Jim]

An LH diagnosis using a Picoscope...

http://www.picoauto.com/tutorials/merce ... ws=a110301

 

[pesuazo]

I though I would give everyone an update. After checking and re-checking, found my mistake.

Had ignition wires swapped on cylinders 5 and 8. No need for the isolators (never got around to buy them). Lesson learned, check and re-check before throwing parts at a "problem".

Glad to report the engine is so smooth you would not know is running unless you hear it and see the belt, pulleys and fan moving. No engine shaking or movement whatsoever.

Power curve is back and pulls like a freight train all the way to red line. Now I remember why I fell in love and bought this E420 and sold my super reliable (and also loved) 300E.

Thanks to all the members.

 

[S500E]

I may also be in need for new caps & rotors. Looked at EPC and above, but have questions and want to check part#'s again:

Distributor caps:
119 158 01 02 (OEM Bosch) - current number?
119 158 02 02 & 119 158 03 02 - old numbers?

Rotors:
119 158 03 31 - current number? what does it mean when EPC says, "Optional with: 119 158 02 31"
119 158 01 31 - old number?
119 158 02 31 - also current number? EPC says, "Optional with: 119 158 03 31"
(what is the difference between 119 158 03 31 & 119 158 02 31)

Bracket:
119 158 06 40 - current number
119 158 04 40 - old number, EPC says "TO BE USED UP ONLY WITH 119 158 01 31 DISTRIBUTOR"

Seal ring:
020 997 05 48

So, you need 2 of each:
119 158 01 02
119 158 03 31
119 158 06 40 (must have these new brackets for 119 158 03 31?)

Thank you.

 

[bing]

following are the correct part numbers:

MB # 119-158-01-02, Bosch # 03367 - M119 distributor caps

MB # 119-158-03-31, Bosch # 04271 - M119 rotors
For models with updated bracket 1191580640 (Bosch 1230328037). It cannot be used with previous bracket 1191580440. 2 per car.


As advised by avid owners, while you are at it you may as well change the insulators , part 1191580188 which should come with the seal rubber rings. Quite pricy for a bit of plastic, think they're about $78. Otherwise you can just get seal ring from MB for about $4!

Check out AutohausAZ.com ,all the above ignition parts are on sale. Quite a saving compared to MB stealers.

Hope that helps!

Cheers
Bing

 

[S500E]

Thanks Bing,

Since autohausAZ caps & rotors are by BOSCH, are these identical to those MB factory parts (parts.com)? Any quality difference between autohausAZ Bosch parts vs MB factory parts? I would like to stay with MB parts in most cases, but these seem to be the same OEM brand at less $ at autohausAZ. Thanks.

 

[S500E]

How do these look? Definitely some buildup and wear.

 

[gerryvz]

Since autohausAZ caps & rotors are by BOSCH, are these identical to those MB factory parts (parts.com)? Any quality difference between autohausAZ Bosch parts vs MB factory parts?

Caps and rotors are an EXCELLENT example of when to definitely use AutohausAZ.com for parts. These Bosch branded parts are indeed exactly the same as the MB factory parts.

HOWEVER, don't automatically assume that AutohausAZ.com is cheaper with all parts than parts.com is. Just recently I ordered two brake rotors for my C126 560SEC coupe. The factory rotors for this car from MB were significantly cheaper than the rotors available (quality aftermarket) from AutohausAZ.com. So go figure.

I would not hesitate to order the Bosch caps and rotors from AutohausAZ and one would be crazy not to, in terms of saving money over the MB boxed parts which are functionally identical.

How do these look? Definitely some buildup and wear.

They look to me to be in actually quite good shape. I'd carefully clean out the carbon and tracking on the inside of the caps and then take a small piece of sandpaper or a nail file (I raid my wife's cosmetics drawer in the bathroom for such purposes) to file down the metal contact surfaces on the cap and rotor a bit to expose new metal. A good 10 minutes and everything will come out looking (and functioning) like new.

Cheers,
Gerry

 

[bing]

S500E, My caps looked identical yours before I recently replaced them. I did this because I was getting a misfire and I coud'nt see from old invoices/service records that they were ever changed by the previous owner. So as to eliminate other possible cause I ordered from Autohaus complete set, caps/rotors/insulators (leads and plugs were changed on the last service) and now the car runs smooth. However, if your car is not running bad and no misfire I would go down Gerry's route - clean them for now!

Bing

 

[S500E]

Thanks gerry and bing for your input. I'll go with autohausAZ parts for these in the future. At least $60+ savings per each side vs MB factory parts. Mine were cleaned by a local MB mechanic less than 3 years ago. Not sure how old these parts are though. No major issues at this time. I just noticed rough idle once about few weeks ago (engine was warm), but it is not doing it anymore. I'll try cleaning them for now and see it anything funny comes back.

 

[J-Sauce]

Any chance I can pull the brackets off a 94-94 parts car and just replace my early style with them? Sounds much easier than paying ~$60 each for them. (avoiding the crap URO $22/ea parts, although I doubt they could really screw something like that up I still refuse to give them my business)

 

[gsxr]

Justin, are you sure your car has the old style brackets? I'm not sure if these were used on USA cars... I suspect they switched over prior to the 1992 model year, but I'm not sure. Check your part numbers, if you haven't already. And no, I wouldn't use URO junk. Get them from a parts car if you need 'em.

 

[JordiC]

Gents, are the insulators supposed to spin freely and loosely when the distributor caps are removed? I noticed this the last time I removed the caps and wasn't sure if this was by design or if something wasn't tightened.

 

[vexed]

Gents, are the insulators supposed to spin freely and loosely when the distributor caps are removed? I noticed this the last time I removed the caps and wasn't sure if this was by design or if something wasn't tightened.

As I recall yes they do spin. The raised edge of the insulator fits into the channel on the cap and that is what prevents them from moving.

 

[mb280sel1985]

Hi, how to go about replacing the rotor bracket/adapter? Is it just the one screw, or is there more to it? Heard something about timing the cams..

Reason: I need to clean the bracket, and also the orange insulator cup.

This orange seal ring - what kind of locktite should be used together with the seal ring?

I have a combination of:

Insulator: 1230500240
Bracket: 1191580640
Rotor: 1234332422 (autohausaz)
Cap: 1235522430 (autohausaz)
Will get seal ring from MB: 020-997-05-48

What would be a good reason to replace the insulator and bracket?

The caps are allways moisty after 5-10 mins of driving. How to stop this..?

 

[mb280sel1985]

So I detached the rotor bracket and wow what a mess behind the insulation cup, and a mix of water and oil sitting on the surface of the cup!

Is this normal? Am I missing an orange seal ring here?

Please share your thoughts..