Replacing Starter Motor

[Mike K]

I finally got around to replacing my starter motor today, the starts have been getting lazier and lazier despite having installed a new more powerful battery. There was previously a discussion in this thread: http://www.sl113.org/forums/index.php?topic=21743.0

This is something I've been putting off doing for a while, having ordered and received a remanufactured mint condition Bosch starter motor several months ago from here: http://www.oscaro.com/demarreur-bosch-0-986-010-850-75222-2-p  
Out of interest: €198- compared to +€400- from SLS.

I followed the instructions provided by "Kampala" (Oz) in the previous thread, and the job was far more straightforward than I expected.
Disconnect the battery.
There are 2 bolts to loosen, the top bolt from inside the transmission tunnel inside the car and the other from under the car.
I first lifted the carpet, opened up the panel on the passenger side of the transmission tunnel and inserted a ratchet & extensions with a 10mm hex drive, its tip covered with Prestik which is a gum-type adhesive, so as not to drop the top securing bolt into the abyss.....

I then jacked the front of the car up and placed jack stands underneath; working on my back under the car, removal of the starter motor took less than 15 minutes.
What did shock me was the poor condition of the wires, including the + battery cable to/from the battery to the starter motor. I replaced the + battery cable as well as the 3 wires which run to the bridge on the side of the sump pan.

In fact the rewiring took a couple of hours to do, including cutting and fitting new wires, ring connectors, insulation and fitting the new + battery cable, feeding it around the sump pan & through the grommets to the starter motor- all very straightforward.

As the new replacement starter motor is about 2/3 of the weight and size of the older model, it's far easier to work with and there's more space to position the new wires around and away from the exhaust manifolds.

My suggestion to anyone undertaking this job is to:
1. if replacing the wires, firstly fit and secure the wires to the starter motor prior to installation on the car- so much easier than trying to do this from under the car. Make sure that you position the wires so that they will be clear of the exhaust manifolds.
2. position and bolt the starter motor into place starting with the bottom bolt from under the car and then tighten the top bolt from inside the car.
3. then finally connect the wires to the bridge at the sump pan

The difference in cranking power is astounding, it's a totally different car!

Best,

Mike

[ja17]

Good tips, advice and photos Mike!  Thanks.

[Scottcorvette]

I would like to use on of these reduction gear starters on my 230SL, is there a Bosch part number for that model?

[Naj ✝︎]

I would like to use on of these reduction gear starters on my 230SL, is there a Bosch part number for that model?

BTW, its not a reduction gear starter, just a normal straight drive, but more powerful.

Bosch # 0 986 010 850

naj

[Mike K]

FWIW, this evening I was going through a couple of Kent Bergsma's videos on Youtube, mainly relating to fuel injector cleaning. By chance, I came across the video relating to starter motor replacement: https://www.youtube.com/watch?v=OrXW4i88zhk

He's usually got some good advice & tips, (despite the irritating voice   ), but in this video he makes a mountain out of a molehill with the technique he uses in replacing the starter motor.
He would be well advised to take some advice from our experts on this forum   , (whose advice I followed when replacing the starter motor), which is that there's a far easier way to do this by going through the transmission tunnel & using about a 1 foot ratchet extension, rather than the +3 foot long ratchet extension arrangement that he uses from half way down the back of the car....

Best,

Mike

[troctime]

Hi there,

Just a small question.

Will the same (new smmall and more powerfull) Bosch starter work on my 230SL from 66 ?

Thank you all,

regards,

Olivier

[ja17]

Yes, it will work just fine. Seems that there may be a minor hardware problem, might have to add a nut to one of the mounting bolts,  can't remember for sure.

[swood1]

Is the 0 986 010 850 part number for the LHD car?  I think they are handed.

Regards

Steven

[Naj ✝︎]

Hi, Steven,

Yes, the nose cone on starters on RHD cars are different but I had no problems fitting a LHD starter on my RHD car with manual trans.

naj

[troctime]

Hi,

What did I do wrong ??

I ordered the BOSCH  0 986 010 850 ( delevered today from OSCARO )

I think I did receive ( see both pictures ) the big old one and not the small stronger one.
On the package it is printed remanufactured in germany 12v 1,5kw

My questions :

- Will this starter firt in my 230SL from 1966 (I think it was not the same ref for 230) ?

- Is the one I receive stronger than the old one (to have better start) ?

Thanks for your advises,

Regards,

Olivier

[450sl]

You picture looks like its a refurbished  starter motor. Some suppliers want the old one in exchange.

[troctime]

Yes it's a refurbish but I didn't send my old one (still on the car).

Do you think this starter firt in my 230SL from 1966 ?
And the refurbish I received will be stronger than the old one ?

Thanks,

Olivier

[Naj ✝︎]

Hi, Olivier,

The starter you have received is the early heavy type but it is the higher powered one (1.5KW instead of the early 0.8? KW.)

It should fit OK on your 230SL

naj

[ja17]

Yes, I agree with Naj.  Look for the 1.5 PS stamped on the case. Also the more powerful starter has three screws holding the solenoid in place instead of two as in your original. Most owners are opting for the new "reduction gear"  type starters. they are smaller and more powerful than the other two. They do sound different, if that matters to you.

[Tyler S]

Oliver, I replaced my starter with that exact same unit on my 250sl.  Made a world of difference. Look at the bottom mounting bolt hole on the new starter and see if it is threaded. If not you will need a longer bolt and a nut to mount the starter. I used an old head bolt to do this.