Loud Cracking sound from rear crossmember

I've been hearing a cracking sound whenever I take hard corners, accelerate from a stop up a hill or brake hard. It sounds like metal breaking into two. I think I figured out what it is, but need some help with my next steps. Attached is a picture of the bolt that I think is causing the problem. It is the one right above the jack. When I jack up right here one or two pumps, I hear the same cracking sound that the car makes when cornering hard. Maybe this bolt is bent or maybe it's not as tight as it should be. Does anyone know the torque spec for tightening this bolt? There is a bolt above this one, so if I take out the bolt to inspect it's condition should I put a jack under the cross member so that upper bolt doesn't buckle from the weight of the engine? I think most people recommend jacking up the car from this area when placing a jack stand in front of the rear wheels. Could this problem have been caused by jacking up too close to this bolt?

Well u 100% should not be jacking the car up from that point. U should be about 6" to the left under the sway bar mounting bolts. U r jacking on the crossmember and not suspension mounting structure. There r 4 bolts that hold that crossmember on and they can be loose or the crossmember can be broken. Its prettt easy to remove and check if u supprt the car using jack stands under the supports in front of the rear tires. U r under #6 but should be under #1

Thanks for the advice De Jeeper. I was actually following the Pelican Parts instructions and they recommend jacking from that spot --> https://www.pelicanparts.com/techart...p_Your_Car.htm Yes, I think one of the bolts is loose. Do you or anyone else know the right torque settings for the four bolts that mount the crossmember? I can't seem to find that information...

You can ballpark it by referencing the bolt size. Or increase the torque on your torque wrench on the other bolts until it clicks (if only a single bolt is loose).

Thanks Ivansskoro. I read somewhere that since the crossmember is aluminum the torque will be lower than what the bolt size suggests. But that is a great idea to check the other side and find out what torque that is set too. I'll give that a try.

I do have a broken x-member at the bolt holes so it might be worth removing to check. U have the specs at home maybe someone has it near them and can look them up. If u r gonna work on these cars buy this. https://theknowledgegruppe.com/produ...96-automobile/

Thanks! I'll be buying that book. I have the Bently manual, but there is no mention of the crossmember torques in there. From the outside without removing the bolt, I didn't see any cracks in the crossmember, but I was only looking around that bolt area from the rear of the car. To remove that bolt should I jack up on the cross member to help support the engine?

No support the car on the factory jack points in front of the rear tires. The x-member does not support the motor. It stiffens the suspension laterally. Mine was cracked at the upper bolt area, drivers side.

Thanks De Jeeper. I ordered the book. Eager to get this done though before it arrives. So, if anyone has those torque specs for those four cross member bolts handy I'll be grateful and able to tighten them down this weekend.

The cross member is attached to the side members using 4x M12x1.5 bolts. These are tightened to 81 ft-lbs/110 Nm.

Great, thank you Hardtailer!

That fixed my cracking sound. Thanks everyone!

Quotes source post: 19691804

Sooo? Just a loose bolt?

Haha, yeah, that cracking sound had me worried for awhile, but just a loose bolt. I saw on Rennlist that someone had a air-cool 911 with the same issue, so that helped diagnosis it. Both bolts on the driver's side were a little loose. Didn't tighten them much, maybe 1/8 or less of a turn. Just drove it pretty hard and no more cracking sound.