Torque Specification Front Axle (sub-frame)

[Buckeye]

In process of rehabbing front suspension and not sure what is the correct torque specification to fasten front axle beam (sub-frame) to frame rails. Haynes manual says 52+4 ft-lbs. and BMW Service book does not exactly uses similar term "front axle beam/sub-frame to frame rails", but it says "Front Axle Beam to Engine Mounting". So like to ask experts which one is correct?, and if neither one, what should be? I have included front axle torque specification here for reference and verification.

 

Thanks,

FA

 

[carlkkreienkamp]

Walter-my boss at his foreign car service in St. Louis always said"gutntite" for those bolts not otherwise specified.

[jgerock]

Did you take a look at the FAQ torque listing in the archives?  I just looked at my printed copy and it only has the rear subframe to body spec (about 100 lb-ft).  I know I have this somewhere 

[jgerock]

Haynes 2002 manual shows front cross member bolts at 52lb/ft.

 

haynes 320 manual says front cross member bolts at 133-145 lb/ft

 

 

[Son of Marty]

If I remember right  they are 10 mm bolts so 55-60 ft/lbs would be about right

[Buckeye]

42 minutes ago, jgerock said:

Did you take a look at the FAQ torque listing in the archives?  I just looked at my printed copy and it only has the rear subframe to body spec (about 100 lb-ft).  I know I have this somewhere 

I did and no indication of sub-frame to frame rail there

13 minutes ago, jgerock said:

Haynes 2002 manual shows front cross member bolts at 52lb/ft.

 

haynes 320 manual says front cross member bolts at 133-145 lb/ft

 

 

I recall Haynes calls for 52+4 ft-lb, and tried it on one bolt, but felt like I couldn't reach final torque (click), so I stopped.

So still looking in the BMW service manual, but dice. I have read people sheared off bolts at this assembly joint before and I want to avoid that.  

[Son of Marty]

A lot of the bolts will shear when they are loosend due to rust, when installing them they are a tight fit and any miss alignment of the subframe or body due to accidents will cause one or more of them to cross thread with disaster following shortly.

[Buckeye]

here are the facts found regarding sub-frame bolts: they are M10x30 and M10x50 grade 8.8

According to Tightening Torque Value chart in the Introduction section of BMW 2002 Service Repair Manual

 

torque value for a M10 thread bolt grade 8.8 is 4.3+0.5 mkp or 30.96+3.6 lb/ft

 

My conclusion is that the values given in Haynes manual (52+4 lb/ft) is incorrect.

 

Thanks for all your inputs.