Loose suspension bolt.

[D2M]

I was at my local track today and noticed the car started to squirm to the left when I did a hard shift. I jacked the rear of the car and checked for play, sure enough there was slight play in the left rear wheel. Removed wheel and proceeded to feel around all the joints for play. The rear upper control arm inner joint was the culprit. I thought the joint was bad and I would have to replace the arm. I decided to check the bolt just in case and sure enough it was completely loose. I tightened the bolt and all is good. The bolt /nut is not easy to get to as the axle is right below the nut and there is only a small gap to get the bolt on top. Please check these bolts on your Z/28 if you track your car. The bolt is highlighted in the pic below. The left front wheel bearing failed as well on this day but that is unrelated.

[BUBZ28]

My car feels nervous, like the rear wants to go left as well, at full throttle in 2nd and during a fast upshift from 2nd to 3rd at redline. Thanks for the reminder that I need to check that everything is torqued back there. That bolt will be the first thing I check.

[Stephen12ZL1]

thanks for this information! I am going to check mine before my next track day!

[cdb95z28]

Thanks for the heads up, my passenger side was loose.

[Mikebrinda]

Does this rise to the level of requiring an government official recall to have checked/fixed for free at the dealer? What if tightened, only to shake itself loose again?

[JusticePete]

If a bolt tightens up, it is working.
If a nut comes loose, it is working.

EVERY-TIME you take a car to a road course it should go through a Life and Death Check. With the car on a lift, you lay a wrench on EVERY nut and bolt in the suspension and drive line to verify they are tight. Race cars are completely torn down and the fastners replaced between races.

After a road course event, your car goes back on the rack and you lay a wrench on every nut and bolt to make certain nothing has come loose and your automobile is safe to drive on the street.

As an alternative, you could drill and safety wire the nuts, but if I am driving on a road course, we are still doing a Life and Death Check before the vehicle hits the track.

[D2M]

This particular joint is not a bushing but a metal heim style joint so it will not absorb any shock but send all vibration and shock load through to the bolt. Im not %100 sure its a metal to metal joint but its some kind of hard joint with a boot not a bushing.

[JusticePete]

Originally Posted by D2M

This particular joint is not a bushing but a metal heim style joint so it will not absorb any shock but send all vibration and shock load through to the bolt. Im not %100 sure its a metal to metal joint but its some kind of hard joint with a boot not a bushing.

Everything you need to know is on our website.

http://www.jpssonline.com./the-book-...ar-upper-inner

We have seen a handful of failures, just enough to replace the factory short shouldered bolt with a full shouldered bolt. Even a full shouldered bolt won't prevent a failure like this is the bolt is loose.

[Mikebrinda]

Originally Posted by JusticePete

If a bolt tightens up, it is working.
If a nut comes loose, it is working.

EVERY-TIME you take a car to a road course it should go through a Life and Death Check. With the car on a lift, you lay a wrench on EVERY nut and bolt in the suspension and drive line to verify they are tight. Race cars are completely torn down and the fastners replaced between races.

After a road course event, your car goes back on the rack and you lay a wrench on every nut and bolt to make certain nothing has come loose and your automobile is safe to drive on the street.

As an alternative, you could drill and safety wire the nuts, but if I am driving on a road course, we are still doing a Life and Death Check before the vehicle hits the track.

Great insight. My concern is that the bolt works loose on street driving alone.

[JusticePete]

Originally Posted by Mikebrinda

Great insight. My concern is that the bolt works loose on street driving alone.

It is possible, not probable. Now if you live in Detroit where most every road is worthy of being named 'Rough Road Test Track', it might be probable

[Mikebrinda]

Originally Posted by JusticePete

It is possible, not probable. Now if you live in Detroit where most every road is worthy of being named 'Rough Road Test Track', it might be probable

I'm not an industry insider so I don't know what types of problems rise to a level that attracts the governments recall attention, but I don't like driving while wondering if a suspension bolt has worked itself loose. Maybe I'm wimping out here. Maybe these type of failures just happen and are accepted with a shoulder shrug, within the margins of acceptable failures.

But it just doesn't seem right that this bolt, holding these parts together, can work itself loose and us owners don't receive a notice to bring our cars into the dealer.

[frenchsquared]

Who says the dealer knows.

[JusticePete]

Originally Posted by Mikebrinda

I'm not an industry insider so I don't know what types of problems rise to a level that attracts the governments recall attention, but I don't like driving while wondering if a suspension bolt has worked itself loose. Maybe I'm wimping out here. Maybe these type of failures just happen and are accepted with a shoulder shrug, within the margins of acceptable failures.

But it just doesn't seem right that this bolt, holding these parts together, can work itself loose and us owners don't receive a notice to bring our cars into the dealer.

Originally Posted by frenchsquared

Who says the dealer knows.

Any bolt can work loose.

A bolt from the factory may be torqued to high, to low or just right. The same is true for a nut and bolt installed by the owner or a shop.

It isn't just these two bolts mentioned in this thread. It is ALL the bolts.

This is another example of why a Life and Death Nut and Bolt Check is critical before taking any car built by any company out on track. The more track miles you put on you Z, the more critical the Life and Death Check is.

We do this on every car we touch. On track cars I may have three different guys do the exact same check if it is a beast of a car with a matching beast of a driver. The closer to the edge the driver runs, the more important even the smallest details become.

Short Answer -- Get your Z on a lift. Replace those two bolts with full shoulder bolts. Use LocTite. Use a vibration proof fastener like this.



Torque it down and periodically check it.

Or just send your Z to me

[D2M]

I fully removed the nut / bolt and blew any debris out of the hole with compressed air and inspected the joint. Cleaned the bolt, put a bit of red locktite and torqued it till it smoked + 1/4 turn, marked it with paint. I will definitely keep a close eye on this.. On the other hand the bolts for the front caliper an wheel bearing that also failed must have been tightened by the Incredible Hulk, guessing he ran out of juice when he got to the back of the car.