300E 103 timing cover re-seal. New cap?
 

I'll be doing the timing cover re-seal on my '88 300E 103 engine 45K miles this weekend. Would this be a good time (45K) to replace the cap and rotor? $75 seems a bit steep. Also, wires: Beru or Bosch? Thanks.

Brad in MA

Not necessarily. It's an easy job later. Replacement would depend upon its condition.

Well, mileage-wise, it seems the 103 distributor,cap, rotor, and wires will go at least 100k and still look and perform great. The wires are copper strand, and cap and rotor have huge spark areas and are super-beefy. But if they are 20 years old, that might be an argument for replacement, especially the wires.
That being said, I recently replaced the original wires on my '91, at 180k miles, just because I thought I oughta, and hoped it might fix a little warm-start stumble.
The old Berus (I think) looked and checked out just fine. But they were pretty stiff and hard to pull loose from the plugs. I used Bosch replacements, they seem equal or better in quality than the originals.

DG

I was doing some work on my 260e the other day...and decided to pull the distributor cap, since I had a spare from a donor car.... the donor car cap was bright orange... the one on the car was faded as was the rotor.

The faded distributor cap looked ok, but as i removed it, the plastic was so brittle it broke in a couple of places.

I am in the process of ordering a rotor. I have a feeling these parts were pretty darn old. Car is running perfectly, but I am the type that likes to replace suspect looking parts before there is a problem.

I order 50-60 dollars of 124 parts each month... of course we have three cars.... but it helps keep me in front of the maintenance game.

However, like the other poster said.... easy job...so not necessary.

The other reason i order and replace parts is that when you don't need them, you have them as spares and can do the work leisurely. I would to be caught in a position of having to pay retail for a part. Consequently, I usually have a box of spares which has come in handy on several occasions...
...ovp, fan clutch and voltage regulator come to mind.

So did I and now I am sitting on a pile of spare parts after my 300CE w124 is wrecked :o. Gotta go thru the hassle of reselling them.

For my next car I won't be buying parts in advance but only when they are needed.

I would replace them. They're already off and 20+ years old. If the car sees lots of city driving/idling then I certainly would. The price is minimal all things considered.

Also, since you'll have the valve cover off, check the breather hoses from the cover to the intake. These are almost always brittle.

I'd think about some valve stem seals too due to age. They're less than $10 and should take 3-4 hours to do.

I guess I was hoping a new cap, rotor and wires would smooth out the idle a bit. Wishful thinking I guess...

Could be MANY reasons why you have that issue.

Ya, I know. I'm thinking injectors. Idle isn't that bad, just feel it could be a bit smoother.

Motor mounts the issue? I did injectors in mine, but I also had 250k on them...

i have owned 5 mb's.. only once had an injector issue...

btw, it was a couple of days before Christmas many years ago, and the tech just popped one out of a junker and put in a new one , gratis.

that was on the 280se.