Sixto:

It indeed does depend on where the pointer was when you started. That means, of course, if it doesn't point to the correct "start" mark loose, it won't tension properly and you will bend or break the tensioning bolt if you try.

I'd strongly prefer a steel spring.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!