Hello, I drive 1991 190e 2.6. (127000 miles) I love this car because it gets good gas mileage and it's built to last, but I have a few questions on a few things that concern me.
1) I was wondering how long do regular brake pads last on an average?
2) I can feel my engine running sitting in my car. It is a mild vibration. Is it time for new motor mounts?
3) What are the symptoms of my flex disc going out?

Thank you for response.

1) I was wondering how long do regular brake pads last on an average?
There are so many variable to give a good answer to the phrase "average." How do the brakes feel to you when stopping and do you notice if your stopping distances are getting longer? The brake sensors built into the pads will give you a dash light indication when the pads are getting thin. I would have your brakes checked annually, since it's good to check the rotors and the brake hose too.

2) I can feel my engine running sitting in my car. It is a mild vibration. Is it time for new motor mounts?
If they're not been changed already, they would be suspect.

3) What are the symptoms of my flex disc going out?
Remember there are two flex discs, so have them both looked at too on an annual basis. Flex disc wear will cause the prop shaft to wobble, causing vibration and possibly some contact by the shaft to the chassis. You'll hear it.

In my experience MB specifies a pretty soft friction material in their stock pads so if you're using OE or OEM pads they may only last 20k miles or less if you use them hard.

I went to Metalmasters a long time ago to reduce dusting. Metalmasters have a good deal harder friction material so they last me 30-35k miles, even though I use them pretty hard. The downside is that they are more prone to sqealing and the pedal effort is a little higher.

Some people don't like Metalmasters for those reasons but the squealing can usually be solved by liberal application of well stirred Permatex anti-squeal compund to the backs of the pads. I do it a day or two before installation to allow the compound to "dry".

HTH,

MikeR
'93 190E 2.6 Sportline

Upon the advice of a MBCA member about ten years ago I installed a set of Repco Delux (not Metalmaster) pads. The expectation was for less dust, less squeal, long life, and low rotor wear. The downside is that more pedal effort is required, and I knew that going in.

I installed them at 15K miles and based on wear measurements I've made since then, I expect to begin thinking about replacing them at about 90K miles. I'm currently at 74K.

A bit of idle roughness - an uneven random vibration of variable frequency - appears to be the nature of the 103 engine. I think it's more noticeable on manual transmissions idling in neutral, than an automatic idling in Drive. Modern engines idle at stoichiometric A/F ratio rather than about ten to 20 percent rich as in pre-emission engines, and the leaner idle mixture causes some idle roughness. If you rev the engine up to 1500 to 2000 the roughness goes away. The idle roughness is probably the interaction of low idle speed, valve overlap, and the relatively lean (for idle) mixture. On my car the idle roughness is not present when the car is running open loop during warmup - probably because the mixture is richer, but once warmed up it's there, sometimes worse than other times.

The flex disc that typically deteriorates is at the front, and it will make the driveline feel rubbery. I can recognize it on my manual transmission 2.6 when releasing the clutch and shifting gears, but am not sure how it would manifest on an automatic. For sure you can see if the front flex disc is detereiorated by visually inspecting it for cracks in the rubber. The front flex disc is specifically designed to have flex in torsion to absorb driveline shock. The rear disk is much stiffer and is much less likely to be deteriorated.

I replaced my front flex disk at 60K miles after finding it cracked during my 15K maintenance inspection (I use the MBZ maintenance checklist that the dealer should give you if you have it done there), and it was probably shot before the 50K mile warranty was expired, but I didn't recognize the symptoms until after I replaced it and the "rubber band" feeling in the driveline went away. I expect it will need to be replaced again after 50 to 60K miles. It's designed to flex and the flexing cracks the rubber. Unfortunately it has to be considered as a normal maintenance replacement item, and if you can get 60K miles out of one, you're probably doing okay.

Duke

I can respond to your second question.

I have a '92 300e with 2.6 engie that had an annoying vibration at idle, especially at a stoplight with the car idling in drive. The engine ran smooth except for the vibration so I suspected the motor mount was the culprit. I put on a new motor mount from Fastlane and the car feels like new now...virtually no vibration.

I read that sometimes a failed motor mount will ooze fluid. Mine didn't. The only evidence was that one motor mount (the bad one) was a little more compressed. You can compare by feeling the rubber spacer on the bottom side of the mount.

Hope this helps.

the idling roughness can be due to 2 things - worn engine mounts and the known M103 idle misfiring problem.

when my 190e2.6 engine is hot (e.g., in summer after starting the engine hot), aside from the idling misfire problem, i even have the misfiring when i rev it, until around 2000 rpm, when it goes away. The best indicator of this is the ecomomy gage showing engine load, with the computer trying to maintain idle speed.

this symptom is very intermittent, but only happens when the engine is hot.

my car has a 5speed manual transmission, and I experience the driveline windup (rubber-banding) not only when carelessly letting the clutch out abruptly, but also when I am on the gas (i.e., driveline is under load) and the rear wheels go over a bump measuring around 2-3inches high by 6inches wide in cross-section. I have always wondered why this happens. So on roads I am familiar with, that have such types of bumps, I let go of the gas when the rears go over the bump (i.e., unload the driveline).
This does not happen in a car with an automatic because of the absorptive action of the torque converter.