240D starter sometimes won't engage - PeachParts Mercedes-Benz Forum

ak_pdx · #1 03-02-2015, 02:47 PM

Hello all, I've been away for a while...

This is a 1977 240D (manual conv) that I've been dealing with for the last 5-6 yrs.
Last year first the alternator failed (replaced w/used one from my "spare" engine), and shortly after the starter failed. Also replaced with a used one (also from the engine I used previously, but that was sitting outside for 1-2 years)

The starter on the first try just spinned fast, on the 2nd started the car. This would happen very frequently, 2-3 or more free spins before engaging, sometimes even started spinning after a few secs of cranking!

Replaced starter with an 'unknown' used one; same behavior.

Decided it's a bad solenoid, bought a German-made new one ($59), installed in the starter from the prev engine. Still spins often, more in cold weather.

Tried to observe voltage at the + cable at the solenoid, no obvious drop when starter goes from cranking to spinning.

Could I have bought a faulty solenoid?

Thanks!

Maxbumpo · #2 03-02-2015, 02:55 PM

Really sounds like the bendix gear / lever part is not working.

ak_pdx · #3 03-02-2015, 03:26 PM

Quote:

Originally Posted by Maxbumpo

Really sounds like the bendix gear / lever part is not working.

Thanks.

The new solenoid came with a plunger/spring that had to be snapped onto the lever that operates the bendix. The lever moved easily and slid the gear back and front when I had it disassembled... Also, this is two diff starters and three solenoids.

What puzzles me the most is that it would back off during cranking.

-AK

Maxbumpo · #4 03-02-2015, 03:35 PM

I think you need to visually inspect the ring gear then, to see if that is worn or has teeth missing.

Also check to make sure you've got the starter fully seated / square. That engine doesn't call for shims to properly space the starter vs. the ring gear, does it? Check the factory service manual.

Not sure on an OM616, on the OM60x engines there is a nice inspection port on the very bottom of the bell housing, facing toward front of the car. It is also where the crank shaft locking plate is screwed down (engages the teeth of the ring gear).

ak_pdx · #5 03-02-2015, 05:39 PM

I thought about the ring gear. (And yes, there's access cover thru which one would unbolt the torque converter from the flywheel on an automatic)

But I think if teeth were worn/missing, how could it work on the subsequent try?

What I couldn't tell is whether there is anything in the solenoid that would only allow the starter to rotate when the bendix is fully extended. (I worked recently on a Ford starter -- there one could see the arm that forces the bendix out makes a contact to start rotation)

-AK