Over the past two weeks my starter engages a split second later than usual about once every 10 or 15 starts. The battery seems to have plenty of juice and the car always starts on the first bump when there isn't this delay. Is there anything I can check so I don't end up in a no start situation before heading off to work? Thanks

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'81 300SD

it'll just keep getting worse. doubt it will just up and die on you. i have experience with three diesel starters going bad. it'll start giving you just a click maybe once every twenty starts. then every ten, then every five. then it'll do it every time, but it'll eventually turn. then it'll eventually turn if you bang on the housing with a hammer. then it'll be completely dead.

you may have some other problem. ground strap corroded or loose? corrosion at the battery? corroded or loose negative cable?

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1981 NA 300D 310k miles

Thanks for the reply. I checked the ground cable and terminal, and everything is tight and clean. I have an extra starter in the garage, but don't want to install it just to find out that there is an issue with the ignition switch.

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'81 300SD

when my starter went out its turning power diminished gradually, but i never saw a late reaction. perhaps the solenoid is at fault and not the motor.

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'77 240D, 504H, OM617.952, etc.

I was thinking of replacing the solenoid on my starter with the one currently on my spare. Is there enough room in a W126 to replace the solenoid with the starter still on the engine?

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'81 300SD

You might could, but I would not want to try it.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Sometimes just loosening the solenoid mounting bolts half a turn cures one that is slow to operate, yes its still has a fault but this helps.
I have had a starter that had rusted up internally and would turn slow.

This is the classic BOSCH solenoid failure .

When it stops fully, you can often make it start by using an unbent paper clip in the terminal box on the inner fender but the smart money is to take the starter off (yes, I know, I do it on hot engines, no complaining) and take it apart, clean and lubricate it , add new brushes (maybe, eyeball them) and install a brandy new BOSCH or (again, -maybe-) Echlin brand solenoid and forget about it for another twenty years .

I have had short lived success with any other brands so beware .

No need to put out big $ for a rebuilt starter unless it doesn't crank with authority, then it's still a maybe, take it to bits and look at it .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

VWNate is right, of course. You CAN redo a starter yourself. When I started wrenching we did all of ours in-house at the Buick dealer. If we redid one and it didn't work it meant it had a bad armature (rare) and we'd get a replacement (we didn't have a growler to check them nor a lathe to turn the brush area). These were the days when there weren't parts stores on every street corner and there were few rebuilders in the business and none in our area.

All that said, we have a good rebuild shop here in Wilmington and they stand behind their work so I have them do my stuff these days. They did the starter and the alternator (both Bosch) on Mutt and everything works groovily. I've decided that I only have so many hours in my day and I need to decide where to spend them. If they do my electrical bits I can do other stuff, like build a race truck.

Dan

Well ;

I've been wrenching since the 1960's so I approach the job perhaps a little differently .

I also got sick and tired of others doing shoddy works so I now tend to try and push the DIY'er to at least trying do fix it them selves....

YOU will usually do a better repair job because YOU CARE .

The BOSCH starter solenoid thing is well known to any older German vehicle Mechanic .

It's a simple thing to add a little cube relay in the circuit between the battery and starter solenoid, this is called adding a " hard start solenoid " and will often allow a few more years out of a dying starter .

It works gangbusters on anything 6 volts .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

Before pulling the starter as the suspect, you want to make sure it is not an electrical issue in the circuit between the ignition switch/neutral safety switch/ starter solenoid. If the key switch does not give you a normal start but jumping the terminal block does, then the circuit mentioned above is suspect.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

A slow solenoid will quickly kill the electrical contacts, as the contacts will only survive if smacked together quickly.

In many cases it is a simple matter of opening it and cleaning all of the old thick grease that is making it move slowly when it's cold.

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Gone to the dark side

- Jeff

That usually works very well on the older typ of Delco Remy solenoids but not so much on the BOSCH ones, I am not sure why this is so .

If you take a solenoid apart, be sure to POLISH the internal contacts ~ never, EVER use sandpaper etc. on electrical contacts .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better

A Bosch starter solenoid like the ones on 617.xxx engines cannot be taken apart to "polish" the contacts. The solenoid is crimped together and not easily taken apart without ruining it.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Last night and this morning I realized that there is only a delay when the engine is warm. I jumped the wires at the terminal in the engine bay and got a click, but no crank. I have a spare starter that worked well on my old engine. I think I'll just swap that one in. Do I need to remove the steering damper or anything else to make room for the starter to drop down? Do I need the long swivel socket extension that is needed for the W123 chassis?

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'81 300SD