This is a repost from the alignment thread but I think it's important enough to warrant it's own thread. I checked my 12 subframe bolts and found 8 of them loose. My alignment settings were changing and I couldn't figure out why. Be sure and verify the subframe alignment using the reference holes shown in the shop manual diagram. A large punch will give you more accurate alignment than a screwdriver. If the alignment holes are off then loosen the subframe bolts enough to move the subframe into alignment then tighten and torque the bolts.

On the front subframe I checked the alignment holes and it appears the front subframe is pretty much centered but the two rearmost 17mm bolts were almost finger tight. I put a bunch of Locktite on them and torqued them to spec + 10%. All four of the big 19mm bolts were tight.

All six of my rear subframe bolts were loose. I verified the subframe alignment then removed the four 17mm bolts,one at a time, put a lot of Locktite on them then torqued them to spec + 10%. I made the mistake of removing one of the big 19mm bolts because it was a bitch to re-install. The shop manual says to replace the subframe bolts when you loosen them, I guess that's why. I simply torqued the other big 19mm bolt.

I'm embarrassed I went so long before checking the subframes. Checking these bolts will become a standard inspection for me.

 

Wow, good catch! Definitely something many of us wouldn't think about checking!

-Marc

 

Good tip for everyone pretty useful as I just changed mine. Where did you find these diagrams though I wonder if they have them for different areas with torque specs.

 

The diagrams are from the AP1 shop manual and the torque specs are on the diagrams. 43lb-ft for all the 17mm bolts, 85lb-ft for the front 19mm bolts and 76lb-ft for the rear 19mm bolts.

 

My thanks to you as well. We realigned/centered the subframes after my incident last year and they torqued em' all down, but I am sure gonna go back and check them all before the start of the season. Great post!

Nick

 

Definitely good to know thanks. Makes a pretty good case for Subframe rigid collars as well.

 

Good catch and thanks for sharing!

 

Awesome! Thanks for sharing this, I will be checking mine soon.

 

Same thing happened to me last year. I figured since it was a salvage/rebuilt title mine were loose from the rebuild. My car would dart left or right every time I hit a dip, not a good feeling on track. Kind of felt like 4 wheel steering turning into corners too.

 

I would advice everyone to check this. I checked my rear subframe and all 6 bolts where lose.
There was maybe 30 Nm on them. I never noticed during driving (I don't track though).
Thanks robrob.