rear control arm bolts

doood

Amateur Mechanic
Sep 24, 2020
585
798
93
You guys can turn the most basic stuff into a nightmare. If the original equipment bolts are re-usable, then clean them up and reuse them. People advised me not to use Loctite on the control arm nuts if I ever wanted to get it apart again. I bought both the UMI and BMR control arm braces; neither fit (UMI interfered with my flowmasters, BMR interfered with my e-brake cable), yet both came with.... dum, dum dummmmmmmm: nylon locking nuts. PM me if you want to buy them off me at a discount.

No way these are coming apart if installed with the recommended 80 (nut) or 100 (bolt) ft-lb torque. My guess is the nut came off the 71 Chevelle was simply not tightened. You're supposed to have the nuts snugged, then final torque them with the car on the suspension so that you bind up the bushings at ride-height. If you torque the nuts with the rear at full sag (unloaded), then you will clock the bushings there and they will twist up like torsional springs when the suspension is loaded. Dude prolly forgot to final tighten one of 8 bolts/nuts. That is much more likely than a nylon locking nut walking itself off 10 turns on the maiden voyage.

1713414334781.png


I agree, shouldn't use bolts that don't meet the OEM spec (grade 8 or whatever). Watch out for chinesium. Reuse the old stuff when you can.
 
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mikester

Comic Book Super Hero
Mar 10, 2010
2,923
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Small town NY
You guys can turn the most basic stuff into a nightmare. If the original equipment bolts are re-usable, then clean them up and reuse them. People advised me not to use Loctite on the control arm nuts if I ever wanted to get it apart again. I bought both the UMI and BMR control arm braces; neither fit (UMI interfered with my flowmasters, BMR interfered with my e-brake cable), yet both came with.... dum, dum dummmmmmmm: nylon locking nuts. PM me if you want to buy them off me at a discount.

No way these are coming apart if installed with the recommended 80 (nut) or 100 (bolt) ft-lb torque. My guess is the nut came off the 71 Chevelle was simply not tightened. You're supposed to have the nuts snugged, then final torque them with the car on the suspension so that you bind up the bushings at ride-height. If you torque the nuts with the rear at full sag (unloaded), then you will clock the bushings there and they will twist up like torsional springs when the suspension is loaded. Dude prolly forgot to final tighten one of 8 bolts/nuts. That is much more likely than a nylon locking nut walking itself off 10 turns on the maiden voyage.

View attachment 238010

I agree, shouldn't use bolts that don't meet the OEM spec (grade 8 or whatever). Watch out for chinesium. Reuse the old stuff when you can.
Did you ever see an OEM nylock ? Just sayin... lol
 
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69hurstolds

Geezer
Supporting Member
Jan 2, 2006
8,202
17,609
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Did you ever see an OEM nylock ? Just sayin... lol
Yup. Not on suspensions though. Look at the master cylinder/booster nuts. Alternator battery terminal but it’s tiny. None of those in dynamic situations.
 
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SS_Malibu

Royal Smart Person
Supporting Member
Sep 27, 2021
1,176
2,070
113
Mesa, AZ
Simple fix for those nylock nuts with at least two ways. Probably more but these work. (Best way is to not use them on suspensions.)

1) Drill a cross hole in the end of the bolt and insert cotter pin. More as a safety last ditch. Of course regular inspections would be required.

2) Most preferred way is to hire this particular welder for tack welding. I'm sure she could get my nuts hot anytime she likes. :)
tumblr_p40fqisW6Z1rn8k76o1_500.gif




Nuts are cheap.

M12x1.75
Prevailing Torque Nuts, aka Stover "cone" nuts. They lock based on slight deformation of the threads. Deeper you go, the tougher they bite. Once installed, they're not going anywhere.
shop%20photos%203%20071.JPG
I work at a fab shop and NONE of our welders look like that.
 

-dw-

Greasemonkey
Mar 15, 2021
209
377
63
Central MN
No way these are coming apart if installed with the recommended 80 (nut) or 100 (bolt) ft-lb torque.

Plenty of late model autos have been using nylon lockers on their suspensions. Havent seen any of them come loose or fall off. Not understanding the fuss except someone f-ed up once.
 

L05edSS

Greasemonkey
Nov 29, 2022
209
118
43
FYI, Belmetric sells grade 10 hardened conical locknuts for $0.71 and hardened flat AN style washers for $0.28. You would still have to measure the length of the bolts and price them out.
i bookmarkd bolt depot & may come in use now that i'm familiar with metric #s that were givin me googly eyes.
:itchy:
 
Last edited:

melloelky

Comic Book Super Hero
Oct 22, 2017
4,166
9,583
113
mass
i bookmarkd bolt depot & may come in use now that i'm familiar with metric #s that were givin me googly eyes.
:itchy:
I can't speak to this "one man's nuts are better than another's " but I've used bolt depot for years with good results
 
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