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Starter problem 1977 300d

I just bought the car 2 days ago , and now it will not start … no noise whatsoever , so I take the starter out ( hint … top bolt first ) , I take it to have it checked , Auto Parts store … guy bypasses selonoid… and shows me that it works , I didn’t actually see it engage , but it did sound like it worked . So I put it back into car , planning to bypass the selonnoid for now . … I turn the key on and try bypassing , I hear the starter spin but it does not get to the flywheel …

Testing the current , before removing starter, I noticed that a negative charge was on the selenoid, I didn’t think that was right , turnibg the key made no difference on the current flow that I see at the starter .

Take this starter to a heavy duty rebuild shop they should be able to set you right-Kevin

I agree , except it’s Sunday and I must move the car , so it’s cheap auto parts store I think , Thanks Kevin .

I suppose I might should keep the core though , being actually a Mercedes Starter

Finding a starter on Sunday for a 35 year old Benz diesel?? Not going to happen…

How to test your starter: Remove it. Using jumper cables, clamp the negative cable to the starter. Clamp the positive cable to the post on the solenoid where the positive battery cable was connected. Use a small jumper wire to momentarily connect the positive post to the small solenoid connection point. Have someone hold the starter firmly when you do this as it will jump as (hopefully) engages…

Thankyou Caddyman,

I took the starter out again and took it to the car parts place , this time they checked it as you stated , and it worked fine , me bypassing the selenoid made it so that the starter was only spinning and not engaging , why though is there a negative charge to the small screw area , which I ran a bypass wire to, to tap a positive charge on it , and it is starting up fine now .

Now the glow plug light isn’t coming on except when I giggle the key , and it wont start ( yesterday ) , today the glow plug light working and it starts up fine .

THis car has been sitting for a while and I know there is going to be some bugs to work out of it . Had the lights on yesterday , then pulled the light switch to the out position , right head light went out , put on the brights , both lights work ; play with the light swith again and back to only 1 headlight . : ) . . . this is going to be fun n n n .

Transmission slipping a bit , so I am thinking about taking to the Mercedes Dealer here in St Pete , for adjustment .

The reputation that surrounds these old Benz diesels far exceeds reality…They do not last forever and keeping them running can be very expensive…I’m sure you can find a 300D forum where the true believers gather and share knowledge and trade parts amongst themselves…Taking it to a dealer is asking for a sexual assault on your wallet…

I know someone that could help you find that starter as he pretty much exclusively works on Benzes. PM me if you want his contact info.

Here are some starters.,carcode,1193677,parttype,4152

Your story illustrates the reason for a pre-purchase inspection, especially on a 35 year old MB. Whatever you paid for the car should be considered a down payment – the cost of monthly alimony will exceed the cost of the wedding.

Your questions are best answered here:

My head is spinning. Allow me to try to summarize:

When you turned the key, nothing happened, no click, no nothing.
You removed the starter assembly and the shop bypassed the starter solenoid and tested the motor. It spun.
You reinstalled the assembly, bypassing the solenoid, and the motor spun by would not engage the flywheel.

That, to me, proves definitively that the starter solenoid, the very part that the shop bypassed when testing the motor, is bad.

The solenoid does two things:

  1. it slides the starter gear out to engage it with the flywheel ring gear
  2. it connects the 12VDC to the start motor (through contacts that it closes).

What you’ve been doing to test the starter assembly is bypassing the very part that’s bad. And by bypassing the solenoid assembly on the vehicle, you’ve prevented the starter gear from engaging with the flywheel ring gear.

You need a new solenoid assembly…and new starter assembly if it’s one of those that integrates both.

At this age all kinds of things need a look - glow plugs, injectors (they wear out), and, espcially, valve adjustment. You’ll want to get some kind of repair manual, too.

Never fear ,do a little looking,theres a good bit of info about Mercedes diesels on the net.One thing Europe did good was the Diesel engine,European Diesels are second to none-Kevin