Seat bolts are one-time use?

[SilveradoRST]

Anyone here know if the bolts for the seats (that fasten it to the cab body) are one-time use?  Getting a leather upgrade, shop telling me I need new bolts.

[Grumpy Bear]

Fastener Engineering 101. The only fasteners that should not be reused are those torqued past their elastic limits (Ops or faulty) and those stressed beyond their elastic limits during service. The thing that makes a fastener 'lock' is stretch. Ever note that rod bolts have both a torque value and a stretch value? Checking both insures that the fastener is not faulty. When the fastener is loosened it will shrink back to its original length. All fasteners are "torque to yield" except those used in things like wood or plastic. If a fastener is torqued to a value that stretches it permanently it is junk. 

 

There are a handful of fasteners in a truck I will not reuse that are subject to high cyclic stresses. Rod bolts I didn't install originally and have no record for. Flywheel and Ring gear bolts. Torque to yield head bolts, again I have no way to know the original state. Seat bolts? Leaf spring U bolts? I reuse unless damaged.

 

Next thing you know they will advise replacing your valve stems every time you check tire pressures. 

 

Now, all that said if a dozen bolts is a deal breaker for this guy....humor him.  

[JimCost2014]

44 minutes ago, Grumpy Bear said:

Next thing you know they will advise replacing your valve stems every time you check tire pressures.

Hmm, now you tell me, would have been nice to know twenty valve stems ago

[Phantom 4D]

It's recommended to use new bolts. Mainly from a safety and legal standpoint. Dealers recommend new bolts for that reason. 

 

[tbarn]

Per GM service manual, seat bolts do not require replacement. Should have the old loctite removed and reapplied, however, if it makes you feel more comfortable, by all means replace them. They are not "torque to yield" bolts. Torque to yield bolts should always be replaced. FYI, torque is 33lb ft.

Edited August 12, 2021 by tbarn

[Grumpy Bear]

One of the things I love about physics is it doesn't have a lawyer, you can't prosecute it, you can't sue it and if you listen to it your always safe. Spiral wound inclined planes have been around awhile and are well understood. Problem is, no one cares to understand anything anymore. "Does it make money?". No? Fuhgeddaboudit!