Belt tensioners

[Sven]

I have a belt tensioning problem and need some help. My 68 280sl has a/c and includes the belt tensioner shown in this pirated photo named "tensioner1".  The problem is that the pulley is just the pulley and is missing the tensioning bolt. What size bolt is needed, and is there anything that it needed other than the bolt and nut.

I also have a another pulley not installed on the car that is of a different style (tensionor2 photo).  My pulley has two belt grooves, rather than the one shown in the vendor photo and can accommodate two belts.
   
Which one is correct and/or best to use? how hard is it to remove and reinstall one of these things?

Download Attachment: tensioner1.jpg
67.15 KB

Download Attachment: tensioner2.jpg
2.48 KB

[al_lieffring]

The tensioner in the second photo is for a sedan. The double pulley was used only on the 280sl. The bolt is a shoulder bolt that is used only in this application, It would be very hard to find. possibly a standard bolt with a spacer tube could be made to work.

66 230sl
113-042-10-014715
904/396 blue, Ivory Tex
condition: not-as-rusty-as-before-bucket

[al_lieffring]

Here is a diagram of the frigking compressor bracket and tensioner.



Did I mention that it's been 20 years since I worked on a 280sl
My 230sl has the Kuhlmeister with a different bracket and pulley system.

Al

66 230sl
113-042-10-014715
904/396 blue, Ivory Tex
condition: not-as-rusty-as-before-bucket

[Sven]

thanks al.

looking at the diagram, it is unclear to me how the bolt/nut (288/296) adjusts the pulley and tightens the bolt.  can you help me understand. thanks

sven

[George Des]

Sen, Take a look at the diagram again. The pulley bolts through the long slot in the main bracket into part number 280.The long bolt pushes against the backet as it is turned and the pulley rides either up or down in the slot. This is what adjusts the belt tension.

George Des

[Sven]

Got it. Thanks both of you for the advise.  Any guess as to what size bolt it is?

Sven

[al_lieffring]

quote:Originally posted by Sven

Got it. Thanks both of you for the advise.  Any guess as to what size bolt it is?

Sven

The a/c compressor brackets use a combination of metric, US standard and SAE threaded fastners. As a rule of thumb, if the bolt goes into the engine block it is metric, if it threads into the compressor, brackets or an a/c component it is US threads, As best as I can remember the tensioning bolt #288 is 5/16" US std. threads, about 5" long threaded the whole length. #296 is a lock nut that keeps the bolt from vibrating loose from #280.

66 230sl
113-042-10-014715
904/396 blue, Ivory Tex
condition: not-as-rusty-as-before-bucket