New Positive (+) Battery Cable

[Scottcorvette]

Looks like these guys have everything you need:

https://enginebarn.myshopify.com/collections/all

Might be better for your sanity to buy the loom you need from Authentic....

[Charles 230SL]

I think that cable harness is for an automatic transmission terminal block (I've got a 4-spd).
Scott, thanks for the link to Tom's Engine Barn - they do have everything and I'm putting together a list.

Anyone know off the top of their head what gauge the ignition wire is?  I'd estimate around 14 or 16 but I want to be sure. The loom needs to be large enough in diameter to accommodate it (ignition wire) and the 10 gauge alternator wire.
thanks!

[Tyler S]

Charles, See my repair for this issue in this post below. It would be advisable to change the alternator feed wire to 8ga

https://www.sl113.org/forums/index.php?topic=24660.msg178091#msg178091

[Charles 230SL]

Tyler, yes I saw your post(s) about using 8 gauge (vice 10 ga) wire and I agree that it's a good idea - I just can't find 5/16" & 1/4" eyelets for 8 gauge wire.  Note that I don't have the terminal block used on automatic transmissions so I'd need to run the 8 gauge between the 1/4" lug on the alternator and the 5/16" lug on the starter.  I know this is a ridiculous question, but where did you find those new eyelets for your starter and terminal block? would you happen to recall what gauge you used for the ignition wire going to the starter solenoid?

 

[Tyler S]

I believe I used somthing out of a kit i had. Similar to this. https://www.amazon.com/gp/aw/d/B079BGRQLD/ref=gp_aw_ybh_a_7?ie=UTF8&psc=1&refRID=QM7SVAQ4DV8Q70N0JG0J
Soldered and heat shrunk the connection. 5/16 is just about equal to 8mm

I believe I used 12 ga for the solenoid/ign wire.

[Charles 230SL]

After looking closer at the wiring diagram for an early 230SL, I see that the ignition/solenoid wire is labeled 2,5 vi (2,5mm² cable diameter, violet), which is about 13 AWG. I too will go with 12 gauge for the ignition/solenoid wire.

[Charles 230SL]

Rhode Island Wiring (www.riwire.com) had everything needed (braided wire, ring terminals, conduit, shrink tubing) to restore the section of the harness back to original. I placed an order today with them today

[Kevkeller]

Charles,
What are they charging for the harness?
Kevin

[Charles 230SL]

Kev, I ordered just what I needed to repair my existing harness between the alternator and starter (braided/lacquered primary wire, conduit, shrink tubing, ring terminals, butt splice connectors).

On their web-site (www.riwire.com) they have price listings for Mercedes harnesses - below is an excerpt:

1970-71 MERCEDES BENZ 280SL 113 Chassis
Note: All Connector Plugs and Connector Plug Terminals
Must be Reused from Original Harness
1a. Dash, Engine, and Headlight Harness [std.trans.] 1852.00 .-_-.
1b. Dash, Engine, and Headlight Harness[auto.trans.] 1852.00 .-_-.

Items 1a. and 1b.
015170 and subs.

2. Starter Harness 67.00 .-_-.

3. Transistorized Ignition Harness 89.00 .-_-.
4a. Emissions Control Harness [std.trans.] 446.00 .-_-.
4b. Emissions Control Harness [auto.trans.] 446.00 .-_-.
5. Emergency Flasher Adaptor Harness 125.00 .-_-.
6. Instrument Panel Harness 104.00 .-_-.
7. Body and Taillights Harness 477.00 .-_-.
Chassis# 015170 and subs.
8. Positive Battery Cable 57.00 .-_-.
9. Negative Battery Cable 18.00 .-_-.

[Kevkeller]

Thank you Charles.

[Charles 230SL]

So I received the wires, ring terminals, etc,, from Rhode Island Wiring (RIW) and I restored the section of harness between the alternator and starter.  It came out really nice - everything from RIW was top quality and believe me, it was nice soldering new copper wire on new terminals and then enclosing the wires in the new braided thermo tubing (conduit) they sent. 
I have a 1/4 (stud) B+ terminal on my alternator and while connecting the wire from the starter, I noticed that the ring terminal on the (other) 10GA wire that runs from the alternator into the harness (and thence on to the light switch) was in poor shape. So I snipped off the old ring terminal - and that's when the fun started... for the past couple hours I've been trying to solder a ring terminal on the old 10GA wire (while on my back underneath the car) and I keep getting a cold solder joint. The old wire appears to be covered with carbon and it simply won't permit solder to flow. I’ve cut the wire back several times hoping to find good 'clean' copper inside the insulation but regardless of how far I go back, the wire continues to appear like it's got a black carbon-like coating.  I don't like to use 'crimp connectors' for a harness but I'm beginning to think that a crimp connection may be my only option. 
Has anyone else spiced into the 10GA wire running from the alternator and had this much difficulty soldering? I'm beginning to think Mercedes used some sort of coated primary wire for this section of the harness...

 

[Pawel66]

And the usual ways of cleaning the wire surface before soldering do not work? I mean using the special soldering paste (or other form of cleaning agent you might have there in the US) you use to clean a bit oxidized copper wire? Or just the usual way of sanding off the oxidised or coated layer of the wires with sand paper does not work?

You have to see nice shiny bare copper before you solder it together. Same applies to connector - it also may be coated with something or oxidised.

In a new wire you may get away without using the sand paper if the wire is not coated, in the old one it is very unlikely - you would have to clean it.

Sometimes these wires are indeed coated with protective coat. Then you need to sand it off before soldering, just like the oxidized layer.

If not, then maybe this wire is quite badly corroded and it may need replacement - but let's see what others will say, I am not sure about this and it is a serious conclusion.

In more modern cars the wires can get almost completely oxidised as manufacturers use all kinds of alloys for wires not copper (cost?). Then you just need to replace the wire (e.g. BMW - I was badly surprised how can 7 years old harness look like).

[Charles 230SL]

And the usual ways of cleaning the wire surface before soldering do not work?

thanks Pawell, well, I've used acetone, lacquer thinner, and denatured alcohol to clean the wire, and I use a good quality flux.  can’t really use sandpaper as the wire is made up of many fine strands. I'll just keep at it., at this rate I may end up just replacing the front harness

[Pawel66]

How do I say it n English? Bind those strands together while holdoing them and turning with two fingers until you receive a "solid piece of cable". Then take fine sand paper between two fingers, squeeze that piece of cable and turn in the same way - you will get what you need.

I am sorr I am getting very basic, but if someone is not experienced in this (and I do not know if you are), sometimes these small tips help...

As long as some copper is there - you will get it done.

[Charles 230SL]

as a follow up, I ended up replacing about a 3ft section of the 10ga primary wire running between the alternator and light switch. I got plenty of neoprene tubing (conduit) from RIW so I replaced the looming almost as far back as the regulator. The 10ga wire had oxidized quite a bit over the years and appears to had blackened due to heat.. all good now. thnks all,