Some previous owner welded the end caps on my upper control arms...

[cebra]

Originally Posted by Grumpy old man

" Regarding the 2nd comment, the condition of my threads wasn't great and we didn't trust them holding only under torque hence the tacks. Next time I replace control arm bushings I will have to do the whole thing (arms + bushings) though, it was just a way to get 1 more use out of the arms rather than replace them."


This is why I used the Dykem marker to mark the caps/ control arms . It's easy to check if they need to be re torqued or tack welded after about 50 miles I go over all the suspension and check / re torque everything .

Yeah, that makes sense as well without having to weld. Those threads in the control arm get pretty janky but the first set of control arm bushings lasted 50 years so I guess they worked pretty dang well.

[HO455]

Originally Posted by HeavyHauler

But why does it show 2 different torque specs for lower control arm bushing? One for 160 and another for 280?

Remember these numbers were generated by GM when these trucks were new for the dealers to make safe repairs. In addition parts and procedures were developed to make assembly line processes fast and as cheap as possible. I believe that GM designed the control nut threads to have an interference fit thus negating the need for cotter pins, lock tabs, or other mechanical device to secure the nuts quickly and permanently. By using a high torque value to slightly expand the control arm threads the nut would be locked in position.
If the nuts were ever removed then there would be no need to torque them that tight again as there the interference fit could not be achieved a second time. Hence a lower torque number for reassembly. If you look at the threaded portion of the control arm it is plain to see that there is not enough material there to withstand over torquring of the nut. Which leads us to the welding of the nuts. How many to times were these nuts tightened down with an impact wrench resulting in thread damage by guys hustling to beat shop rate? A quick tack weld would ensure no customer returns after the nut backed off and no need to take the time to get the torque wrench out.

[HeavyHauler]

Originally Posted by HO455

Remember these numbers were generated by GM when these trucks were new for the dealers to make safe repairs. In addition parts and procedures were developed to make assembly line processes fast and as cheap as possible. I believe that GM designed the control nut threads to have an interference fit thus negating the need for cotter pins, lock tabs, or other mechanical device to secure the nuts quickly and permanently. By using a high torque value to slightly expand the control arm threads the nut would be locked in position.
If the nuts were ever removed then there would be no need to torque them that tight again as there the interference fit could not be achieved a second time. Hence a lower torque number for reassembly. If you look at the threaded portion of the control arm it is plain to see that there is not enough material there to withstand over torquring of the nut. Which leads us to the welding of the nuts. How many to times were these nuts tightened down with an impact wrench resulting in thread damage by guys hustling to beat shop rate? A quick tack weld would ensure no customer returns after the nut backed off and no need to take the time to get the torque wrench out.

Thanks for the explanation! It seems the factory control arms should have been a one time use time of part since it is sorta like a torque to yield type of thing. But a tack weld would get the owner another usage without the expense though. I might just re-tack the upper control arms that I have since that will fix it.

[Ironangel]

Originally Posted by HO455

Remember these numbers were generated by GM when these trucks were new for the dealers to make safe repairs. In addition parts and procedures were developed to make assembly line processes fast and as cheap as possible. I believe that GM designed the control nut threads to have an interference fit thus negating the need for cotter pins, lock tabs, or other mechanical device to secure the nuts quickly and permanently. By using a high torque value to slightly expand the control arm threads the nut would be locked in position.
If the nuts were ever removed then there would be no need to torque them that tight again as there the interference fit could not be achieved a second time. Hence a lower torque number for reassembly. If you look at the threaded portion of the control arm it is plain to see that there is not enough material there to withstand over torquring of the nut. Which leads us to the welding of the nuts. How many to times were these nuts tightened down with an impact wrench resulting in thread damage by guys hustling to beat shop rate? A quick tack weld would ensure no customer returns after the nut backed off and no need to take the time to get the torque wrench out.

This! If you ever disassemble control arm bushings you will see that the threads are questionable even in new condition. If you drive and use your truck as it was intended, a couple of 1/2" tacks on rebuilt bushings is GOOD insurance that a production part does not back off or fly apart. You DO NOT have to replace the whole A-arm! Nothing at all wrong with Tacking the end nuts! You just have to be smarter than the A-arm! Grumpy's ideas are spot on for a truck that sees little or no mileage but in the real truck world that ink spot represents an area where a tack weld would have not only 'marked" a location but would have HELD the nut in location as well..."Jus Sayin"

[HeavyHauler]

Originally Posted by Ironangel

This! If you ever disassemble control arm bushings you will see that the threads are questionable even in new condition. If you drive and use your truck as it was intended, a couple of 1/2" tacks on rebuilt bushings is GOOD insurance that a production part does not back off or fly apart. You DO NOT have to replace the whole A-arm! Nothing at all wrong with Tacking the end nuts! You just have to be smarter than the A-arm! Grumpy's ideas are spot on for a truck that sees little or no mileage but in the real truck world that ink spot represents an area where a tack weld would have not only 'marked" a location but would have HELD the nut in location as well..."Jus Sayin"

Do you tack your Upper AND Lower control arm end nuts?

[71CHEVYSHORTBED402]

The end caps were welded on my 71. The welds were very small, I could barely see them. Three or four spots each cap. I can't swear that was factory, but the parts were original.

[HeavyHauler]

Originally Posted by 71CHEVYSHORTBED402

The end caps were welded on my 71. The welds were very small, I could barely see them. Three or four spots each cap. I can't swear that was factory, but the parts were original.

Was there welds on both the upper and lower control arms?

[Ironangel]

Originally Posted by HeavyHauler

Do you tack your Upper AND Lower control arm end nuts?

Just the lowers...The uppers were and still are tight on both trucks...I'm a firm believer in not fixing it unless it's wore out or broken...

[RichardJ]

My alignment guy is old school. No Lazer/computer. He's had the shop for 30 years. He learned from his dad, who had the shop for decades before him.
He tack welds them, "as a matter of course".

[71CHEVYSHORTBED402]

Originally Posted by HeavyHauler

Was there welds on both the upper and lower control arms?

Yes.

Originally Posted by RichardJ

My alignment guy is old school. No Lazer/computer. He's had the shop for 30 years. He learned from his dad, who had the shop for decades before him.
He tack welds them, "as a matter of course".

Be cool if he aligned my truck I've never heard that expression before, I like it.