Author Topic: Torque Units of Measurement from BBB  (Read 2217 times)

WillS

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Torque Units of Measurement from BBB
« on: September 06, 2012, 17:29:33 »
I'm ready to re-mount the rear calipers on my '71 280SL. I've found throughout the BBB that it gives torque settings in either 'mkp' or 'kpm'. I haven't found conversion factors (to lb-ft or Nm) for 'mkp' anywhere by looking in the BBB or on the 'net for them.  'Mkp' doesn't appear to exist. From that same research I found that 'kpm' might be 'kilopond-meter', which converts to Newton-meters (Nm) by multiplying by 9.80665. It looks to me that when Mercedes refers to 'mpk', they might be referring to the same unit, just saying it differently for what reason I don't fathom. After converting 'mpk' (or 'kpm') to Nm, Nm can be converted to lb-ft by multiplying by 0.73756214728 (one Nm = 0.73756214728 lb-ft), which finally gets me to a torque setting my torque wrench understands (lb-ft).

So, for example, the BBB specifies the 280SL/8 rear caliper mounting bolts torque setting as '11.5 mkp' (or 'kpm'??), which converts to 83 lb-ft (11.5 x 9.80665 = 112.776; 112.776 x 0.73756214728 = 83.18 lb-ft). 83 lb-ft seems a bit high to me, for caliper bolts, but maybe not.

What say you, does this make sense, or am I all wet with this? :-\
Wil N. Stevenson
Washington
1971 280SL 4sp a/c  p/s  3.27 diff

WillS

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Re: Torque Units of Measurement from BBB
« Reply #1 on: September 06, 2012, 19:50:10 »
.....or alternatively, does someone know the factory rear caliper mounting bolt torque values for a 280SL?
Wil N. Stevenson
Washington
1971 280SL 4sp a/c  p/s  3.27 diff

Tomnistuff

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Re: Torque Units of Measurement from BBB
« Reply #2 on: September 06, 2012, 23:38:37 »
Your analysis appears to be correct.  The BBB and Haynes manual call for 82 lb(force)-ft, or alternatively, 113 Nm which equals 11.52 kilopond-meters.  I found the information at the bottom of page 147 of the Haynes 230, 250 & 280 workshop manual.
Years ago, I found on the internet a very small but quite slick piece of software to place on my computer desktop.  It`s called Convert and it allows you to instantly convert anything to anything.  You can see what it looks like, and if you like it, download it free at the following web site.

http://joshmadison.com/convert-for-windows/

When I got it about ten years ago, it was free of bugs.  I suggest that if you want to download it, you save it and run your antivirus on it before opening it and running it.  That`s what I would do, anyway.  Or if you don`t want to take a chance and you trust me, I can send an email with it as an attachment.  It`s only 548KB.

Anyway, good luck.

Tom Kizer
Apparently late 1966 230SL 4-spd manual (Italian Version)
Owned since 1987 and undergoing full rotisserie restoration.
Was: Papyrus White 717G with Turquoise MBtex 112 and Kinderseat
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Benz Dr.

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Re: Torque Units of Measurement from BBB
« Reply #3 on: September 07, 2012, 14:15:46 »
I use the same basic setting that I use for wheel bolts which is about 85 foot - lbs. It sounds like quite a bit but it really isn't.
1966 230SL 5 speed, LSD, header pipes, 300SE distributor, ported, polished and balanced, AKA  ''The Red Rocket ''
Dan Caron's SL Barn, K&K dealer since 1989, benzbarn@kent.net, +1 877 661 6061, +1 519 677 5939

66andBlue

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Re: Torque Units of Measurement from BBB
« Reply #4 on: September 08, 2012, 03:51:52 »
For Mac users who cannot use Tom's conversion Windows program here is another widget that will "Convert just about anything to anything else. Over 5,000 units, and 50,000 conversions."
http://www.onlineconversion.com/
Although there are some conversions that neither of the two programs can handle.  
I wanted to have some leather skived and was asked by the owner of the company who was willing to do this, "how much skiving?". "To about 1mm" was my answer. After a brief moment he said "just tell me how many ounces you want", which kept me silent. I told him I would get back to him and started to google. So here are the conversions if anyone else needs them.  :)
http://www.brettunsvillage.com/leather/conversions.html
« Last Edit: September 08, 2012, 04:10:31 by 66andBlue »
Alfred
1964 230SL manual 4-speed 568H signal red
1966 230SL automatic 334G light blue (sold)
1968 280SL automatic (now 904G midnight blue)

WillS

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Re: Torque Units of Measurement from BBB
« Reply #5 on: September 08, 2012, 17:49:50 »
Oh jeez, I use OnLine Conversions alot, dunno why I didn't think of it this time. Thanks all for the info. Test drive of my 3.27 axle this weekend, hope it goes well.....
Wil N. Stevenson
Washington
1971 280SL 4sp a/c  p/s  3.27 diff