1969 280sl fridgiking Ac belt and tensioner setup

[dabigpud]

Been working on a 1969 280sl automatic with fridgiking AC setup. I am unable to find the right belt part number the car sat for 30 years and have it running an driving replacing all the rubber and cleaned or replaced many components to get it running. I can't get the proper belt tension on the belts that run the Ac compressor. Either belts are too tight and or too loose the original belts that were on it had dried out and became brittle tried my best to measure as close as I could. It has a horrible tensioner on it too. Any thoughts?

[wjsvb ✝︎]

For the belt, you need to take a piece of twine and measure the minimum and maximum circumference that the belt will occupy and the cross section of one of the pulleys.   Find an auto parts store with an old guy/gal behind the counter (may be tough in your part of the world!). Take the measurements to the old guy/gal and ask him/her to look up belts available with those measurements.  Start with a belt slightly longer than the measured minimum and you should be OK.  The cross section is key: too large or small, or the wrong spread angle won't work.  As an alternative, Google "V belt supply".  Jon

[Shvegel]

I did a little checking on line and it shows 12.5mm X 1075mm 

[TheEngineer]

You are right: the tensioner set-up is poor. I just pulled the pulley back by hand and found that it gives me the desired tension. And there is another problem: the bottom radiator hose rubs a little on the compressor pulley. I have to create something to pull the hose forward a little. Of course, it is only when the compressor is running and here in Seattle how often is that?