66 230SL with Kuhlmeister A/C Alternator and A/C Belt Sizes?

[DaveinOC]

I've had my 230SL for over 25 years now, so there really is no excuse for me not knowing the belt sizes, but I always thought I could just match them up to new ones. Unfortunately the automotive parts industry has changed dramatically and most places now stock very few belts in ony a few sizes. Here is my setup: with the Kuhlmeister York compressor mounted down low on the right and the alternator up high I have two alternator belts. The A/C compressor is driven by a single belt with its own tensioner pulley. The dual  alternator belts appear to be about 10mm wide and I measured 1115 outside circumference. The closest I can find listed anywhere is 10x1112, which appears to be quite rare. I also measured the single A/C belt as 10x925. I am aware that the dealer installed A/C units had non-standard belt setups and sizes, but I'm stumped on what was originally installed. The car was originally sold here in California so the dealer A/C may be rare also. Does anyone have a similar setup and belt numbers, either MB or aftermarket?

[Mike K]

I had a similar question some time back and never got an answer. Eventually I stuck my endoscope camera into the area below the alternator
and managed to take pics of the sizes imprinted on the belts.

This is for my 280SL:
https://www.sl113.org/forums/index.php?topic=24939.msg178302#msg178302

Best,
Mike

[Pawel66]

I think the key numbers are length and width of the belt in mm. 10x1075 is 10mm wide and 1075mm long. if you take out your belt, you can just measure it if the numbers are not visible.

[TheEngineer]

There is a special fixture to measure belts accurately. Most belt suppliers should have one. It is important to use the right size belt and the appropriate quality. Cheap belts wear quickly and because it is such a hassle to replace the belts you better install the right stuff.

[clunker]

The belt profile is also key, indicated by the leading characters (eg AVX13x1075) on the belt

[DaveinOC]

Thanks for all the tips. I've decided to try 10x1110 for the alternator belts and after taking a closer look at the A/C pulleys a 13x925 for the compressor. The pulley grooves definitely are wider than the alternator and should have the wider belt.

Like others I have had trouble installing the power steering belt so I am going to try an MB 12.5x750 part number 0069970992. All of the aftermarket including the Contitech (nee Continental) appear to be 13x750. Unfortunately it's going to be a little longer than I hoped to install the belts as I've sent out the injection pump and injectors to Jerry Fairchild and I expect it to be a couple of weeks turnaround.
.

[kampala]

The power steering belt is not difficult if you follow what has been described by some of the experts on this site. 

I recently installed a new belt and if you do what they say, it goes on very nicely.   Just wrap the belt best you can part-way onto the power steering pulley after you have put it on the crank pulley, then just use a socket wrench and turn the crank pulley (in the correct direction) and the belt slips right on.  Then tighten. 

I can only advise on things I have done, this is one of them.