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View Full Version : Torque specs for idler pulley and belt tensioner?


JHGould5607
04-04-2017, 03:52 PM
I couldn't find the specs in the service manual for the idler pulley and belt tensioner bolts. Any ideas?

Thanks!

obie
04-04-2017, 04:57 PM
They get German torque.

autostaretx
04-04-2017, 07:45 PM
Their torques may be covered by the chart (Fig 5: Torque Specifications) on page 10 of the Introduction of the 2006 service manual.
Service manual: http://aie-services-2.net/Sprinter/2006-VA-SM.pdf

84640

That's a "generic chart" based upon the bolt size used for that fixture.
I agree that the text of the "install idler pulley" page refers to Chap 7 Cooling Belt installation... but that doesn't say anything about the torque.

--dick

OldWest
04-04-2017, 08:37 PM
Believe there was a page out of repair manual which specified torque for tensioner and pulleys. Maybe for water pump?

https://sprinter-source.com/forum/showpost.php?p=108645&postcount=14

https://sprinter-source.com/forum/showthread.php?t=5317&page=4

Posts 31 and 31-- for earler year.

autostaretx
04-05-2017, 12:09 AM
The belt guide pulleys are 26 ft-lbs (30 N-m)

84646

--dick (getting there one bolt at a time...)

autostaretx
04-05-2017, 12:25 AM
Found it on MB's WIS system...

The torque depends upon your engine/model-year (612=pre2004, 647=2004+)

84648

--dick
p.s. One of the threads pointed at by OldWest had this warning from Dr Andy:
"DO NOT chase the timing cover's belt tensioner mounting threads with a tap. Also, DO NOT chase the bolt threads with a die.

I will post a tech alert on this subject- but for now let me stress that it is important to use the original (new or used), unmolested, 10.9 grade, THREAD FORMING bolts for this highly stressed component. These will NOT install with finger pressure-that's normal. Doktor A "

JHGould5607
04-06-2017, 12:44 AM
Thank you for the replies! Job went smooth.