I'm replacing front & rear shocks, rear sub frame mounts on my 81 E21 and have been searching for torque specs for nuts & bolts. When I look at BMW manual, it will say "Tightening Torque 1" but I can;t find the reference to where the torque specs are.
I looked thru FAQ post but can't see there.
I'm guessing this in front of me and I can't see it - Any suggestions? Thanks
I use the Haynes manual, but there are sometimes reported confusions, or a few typos in it, which is why I sometimes also refer to a standard torque chart for verification. If you use a standard torque chart, you need to know the size and grade of the hardware being used. Of course you cannot use a standard torque chart for 'special' hardware such as engine internals, etc.
Tbd
Torque on nuts and bolts is variable- Grade of steel and dry or lubricated come into play also valves for aluminum are really low ,, Grade Steel 12.9,10.9,8.8 The higher the grade of steel the higher the torque that can be maintained, past that I use a standard guide for nuts and bolts and haynes and few others,
Example
M6( 10 mm wrench size) steel bolt screwed into steel threads(the block)--oil pan bolts-lubricated 8.8 grade-6.5 lb ft ,dry 8.5 lbs-ft , 10.9 grade lubricated 9.5 lbs -ft, dry 12 lbs -ft, , Class 12.9 lubricated 11.5, dry 14.5 lbs-ft,, The harder the bolt the stronger the steel and the higher the torque,, dont use 12.9 class torque for anything other than 12.9, the head can snap off.
You can find these charts all over the internet with nut and bolt makers
Your all welcome,
heads up when buying nuts and bolts see if they are 8.8.10.9 or 12.9,, 8.8 is quite common, 10.9 Servilite and 12.9 class are much harder to find, quite a few nut and bolt makers stamp the bolt hex heads with the class 8.8,10.9,12.9 on top of it, then you know the torque dry or lubricated for each socket or wrench size. Nuts are the same thing 8.8 nuts, 10.9 nuts and 12.9 nuts, have to shop for nuts a little more, generally its better to use same class of bolts and nuts,, both 10.9, both 8.8 and so forth.
I have done a lot of looking into nuts and bolts and classes of each.
Example BMW 26111102144 ( 8 of them) M10x61 mm Guibo bolts Class 10.9 are $6-$9 each,, I shopped around and found the same thing M10x 62mm Class 10.9 for $1.25 each, Made in the USA.
Randy
Last edited by 320iAman; 06-25-2017 at 09:43 PM.
Thanks Free Bird & Randy - this is good info
Bookmarks