Topic: One of the bolts came out of my Extreme Backbone

[kennysabarese]

Had my car up on a lift today for pre track tech inspection and noticed one of the frontmost bolts came out... has anyone else had this happen to them?

[DeepBlueGXP]

no, but I have a clunk noise in the back I need to check on, might be a loose bolt

[rich71]

no i put blue locktight on mine and tightened them to like 30 or something pounds. tighted to it felt tight..... not sure, but the 11 pounds that the manual stated just seemed way too loose. so far no loose bolts or sheared off heads.

[snaponbob]

The factory recommended torque assumes that the fastener is holding a factory part. Well, the factory part is sheet metal and does flex, while the backbone is a slab of aluminum that doesn't. Certainly that will put more load on the bolts and obviously the lower torque number is not enough. Just be careful not to damage the nut threads. That would be a  moment for sure.

[DRGNSLR]

While I also torque many items on the car by “feel”, I also am careful around other parts and try to apply the correct Q for the given part/bolt.   I’m not an engineer but I thought using the OEM torque of 11 lb/ft for the DDM backbone was sufficient since the DDM unit is not that heavy and the clamping force at 11lb is the same whether the part is 10 gauge sheet metal or 1/4" plate.   Also, I was concerned that since the DDM part was thicker than the OEM backbone, I would not have as many threads of the bolt in contact with the threaded bolt hole and I didn’t want to over stress the reduced contact area available.

[Go-N Def]

no, but I have a clunk noise in the back I need to check on, might be a loose bolt

It's probably just another wrench! LOL!!!

[kennysabarese]

DDM installed mine. I don't know what they did or what torque they use. I have an email out to Dave

[Dave@DDMworks]

DDM installed mine. I don't know what they did or what torque they use. I have an email out to Dave

Yes we did, actually if I remember right I am the one that did your install. Not really sure why this happened, did all of the rest of them look fine?

Thanks,
Dave

[kennysabarese]

yeah you installed it at the mod meet. #5 [Edit: 5, not 6 - DBG]

i didn't have a chance to look closely or tighten them, there was a long line at the shop for inspection. i'll be lifting the car up on tuesday so i should be able to retorque them. can i buy the exactly right bolt on my own so i can get it fast?

what should i torque to?