Bolts connecting my rear struts to the frame seem to keep loosening up slightly and causing a knocking noise over really rough roads/frost heaves. Of course all instructions say "be sure to torque to proper spec". Problem is, I have no idea where to find this spec, did some internet/forum searching, dealer doesn't seem to want to provide the info and I don't want to snap the bolts. I have gone as far as 70 ft./lbs. and seemed to last a bit longer but still loosened up.

So three questions:

1. What are the torque specs of the bolts marked at #10 in the diagram below. Connects #9 to subframe of the MINI. Can provide photos if needed still.

2. Is this something loctite should be used on?

3. Anyone have a source for torque specs for the entire MINI? Seems it is an important factor that is almost always left out of instructions/manuals.



Thanks everyone.

 

These specs are normally in the Bentley manual, about $90 through amazon. I will check mine and get back to you. I would think that 70 ft lb is quite a bit for that size bolt. My gut feel is that you should use blue loctite if you are having issues, clean both bolt and hole with brake cleaner first.

Mike

 

+1 for the Bentley manual. I've had my rear suspension apart multiple times and I just tighten it back according to my "mechanical sense". Using blue loctite isn't required since none of the bolts you show don't have it applied at the factory. It's not going to hurt anything applying a little blue loctite to prevent loosening from vibration. I like to use a paint marker on all the suspension bolts and check from time to time if they loosened. I know that bolt #2 for the rear control arms is at least 100 ft-lbs from word of mouth round NAM. That's the only bolt I've ever used a torque wrench on besides the rear sub-frame bolts to the body.

 

Bentley says 41 ft lb for the upper bolts, and there is a note that they are self-locking bolts and should be replaced. I reccomend cleaning both sets of threads and using blue loctite.

The lower shock mount is to be torqued to 122 ft lb. I stripped one of my lower mounts trying to get to this number. Be wary.

Mike

 

Thats what I was thinking too. Generally do things by what makes mechanical sense and go from there. Figured since it didnt have loctite I wouldnt need it now. I am chasing a knocking coming from back there and after checking everything I could possibly think of I noticed these to be a bit loose, tightened them up to 70 ft/lbs for good and it seemed to be fine for a little while. Knocking is now back so I am going to give the grease pen a try and see if that helps show the problem.

This is pretty interesting, never would have thought of a bolt to be one time use but I guess it makes sense for such an important part to avoid any problems. Never heard of anyone replacing the bolts after That being said, I might venture into using loctite if the bolt shows signs of loosening. Also didn't know the lower shock mount needed to be that tight, makes me wonder if that is the knock I am hearing instead since I would assume (not knowing when reassembling) that it is not to torque. Time to get my muscle on Do you happen to know the correct size of the bolt so I can get a perfect fit before trying to get it to spec?

Putting the Bentley Manual on the wishlist, never knew it had torque specs as well in it. Thanks guys

 

122 ft-lbs?! Yikes that seems like a lot for a bolt that's getting screwed into aluminum threads. But we must trust the almighty Bentley right

Did you check the swaybar endlink nuts? If those are just a little bit loose you'll start to hear some knocking.

I would be really surprised if the bolt for the rear lower control arm being just a little loose was making that noise. The mating surfaces between the shock and the aluminum trailing arm are machined to fit together and there isn't much play with the bolt threaded through there. It doesn't hurt to check everything though.