Hey guys, I am rebuilding my front suspension on a 1981 Corvette and was going to clean up and keep the Dust/Spindle shield installed, but as I was cleaning, they were too pitted for my liking, so I am ordering new ones, along with new dust shield gaskets.

Does anyone know the torque specs for the three bolts that hold on the dust shield, knuckle/spindle arm, caliper bracket? There is one large short one on the top and two others on the bottom with one a bit loger than the other?

I searched through my AIM and Shop manual but cannot see these three bolts listed anyplace for torque specs.

Thanks

Here is a picture of the three bolts.

 

Here you go.

 

Thanks Bashcraft! I need to figure out the type of bolt according to the list and just match up the recommended torque.

 

Hi Reaper,
The torque values you're asking about aren't in the AIM because that whole spindle came to the production line already as an assembly.

The 2 lower bolts/nuts should be torqued to 70 ft. lbs. each. They're actually the steering arm fasteners.
That info is found in the Chassis Service Manual in the Front Suspension Torque Section #3.

The upper bolt is an odd one. I Think I've SEEN a torque value for it but can't find it now.
It seems it only use is to position the dust shield correctly.
I'd think 30-40 ft. lbs. (added: based on the info from td2 I think 75 is a good torque number!!!!) would be sufficient since there's no worry about it loosening because of the 2 tabs on the shield that secure it in place.

Regards,
Alan

 

That is very helpful, thanks Alan. Perfect!
Only information I found online, people were still unsure, some said 120 pounds on the upper, but that seems a bit too much since it only holds on the top of the shield and has the two tabs to lock it in place as you mentioned.

Randy

 

Hi Randy,
I agree.
While it's a heavy bolt, (I'm unsure why?), it's only a GM grade 280.
??
Regards,
Alan

 

Alan, the large threads are from the days when wheel cylinders were held on with just one anchor bolt.
Mike

 

Hi Mike,
Thanks!
That exactly the kind of stuff I don't know and you do!!
Do you know a place where the torque value for that bolt is given?
Regards,
Alan

 

Hi Alan, I have never seen a torq value for this bolt. I tighten them to 75 with a drop of red Loctite.
Mike

 

Hi Mike,
Well coming from you I think I'll feel safe recommending that to folks if/when they ask in the future!!!
Thank You!
Regards,
Alan

 

Thank you guys!

 

I've cleaned up the bolts and locking nuts and was going to reuse with some blue thread locker. The locking nuts feel like they still have friction when test fitting.

Does anyone know if it is okay reuse the locking nuts for the two bottom spindle/dust shield bolts? Or is it recommended to pick up some new locking nuts at the hardware store?

Thanks

 

Hi R,
I've reused my originals… they've been re-torqued for the second time AFTER leaving St.Louis.

After reading your question I googled and this is what I found:
This paper presents results from tests on the reuse of locknuts with a prevailing torque locking feature. Aerospace and non-aerospace products are tested. Many qualification specifications provide reuse requirements for prevailing torque locking features in terms of unseated reuses. This paper provides data for comparison of locknut reuse for unseated and seated to preload conditions. All locknuts tested, except one, maintain required prevailing torque levels over 15 unseated reuses as typically required. The unseated reuse tests exhibit a moderate decrease in prevailing torque with reuse with the largest decrease usually occurring during the first reuse. The effect of seating to preload is a higher loss in prevailing torque compared with the unseated results. Reuse in seated conditions does not generally meet unseated requirements. Between 10 and 25% of the assembly prevailing torque is lost during initial seating to preload. This loss continues with reuse but at a lower rate. However, inconsistent fluctuations in prevailing torque are observed for tests with high preload of 85% yield strength of the bolt. For all the seated to preload reuse tests, the tightening torque to achieve a set preload increased with reuse, despite the corresponding reduction in prevailing torque. This phenomenon results from the breakdown of the solid film or as-received lubricant provided with the locknuts.

Amazing?!?

Regards,
Alan

 

Thank you Alan!
That is amazing they were tested and held torque 15 times. I guess after only removing once in 36 years these are good for several more front suspension rebuilds.

I plan on putting on a few drops of Blue Loctite threadlocker for good measure also besides tightening to the correct torques specs you shared, so they should hold for a long time.

Randy