Suspension Fasteners Are Not Reusable?

[Thermo1223]

Originally Posted By: asand1
The dealership I worked at VW/Audi, Subaru,GM did NOT replace fasteners in ANY vehicle. It is just a matter of liability.


I can't comment on GM or Subbie but with VW/Audi they were fools. Probably did it to insure repeat business when something happened.

 

[Silverado12]

I would reuse with loctite.

 

[WINO]

Originally Posted By: SubLGT
I was surprised to see in my Subaru service manual that if you remove and reinstall the front lower control arm, none of the fasteners (3 large bolts and two locknuts) are to be reused. I can see why you don't want to reuse the locknuts (because they lose locking tension), but why can't the large bolts be reused? They get tightened to 70 ft-lb or 110 ft-lb, depending on the bolt.

Do the instructions to replace the fasteners come from the Subaru legal department (CYA), or is there an engineering rationale behind it?



It the threads are good on removal just check the prevailing torque by trying to install the nut by hand. If it stops at the crimped portion of the nut reuse it. You can always use blue locktite on it for extra confidense it wont fall off.

WINO

 

[another Todd]

Why all the paranoia? Of all the millions of vehicles on the road, how often do you see a failed bolt in the size we are looking at. If you hit something hard enough to cause those bolts to fail, the failing bolts are the least of your problems. They are not going to fail just driving around. I say reuse all of them, with locktite, and sleep well.

 

[Cujet]

Silly requirement.

You won't be able to get those bolts to fail, no matter what you do.

It is true that some bolts lose "some" of the ability to "stretch" after use. However, there is no magic to the steel used. They are likely 125KSi or greater in tensile strength. Tough as nails (actually, a lot tougher) and the steel won't lose strength through use or torque cycles.

Head bolts, used in tension only, need to stretch. Re-use, can, at times, result in less stretch, and less reliable head gasket sealing under high stress conditions, such as high boost applications.

These bolts are in shear. No worries.