Suspension and Chassis Questions about your suspension? Need chassis advice?

Replacing control arm bolts

Thread Tools
 
Search this Thread
 
Old 03-13-2023, 04:06 PM
  #1  
Member
Thread Starter
 
taguy16's Avatar
 
Join Date: Nov 2022
Posts: 193
Likes: 0
Received 8 Likes on 7 Posts
Replacing control arm bolts

Is it a good idea to replace your front control arm bolts when upgrading to poly bushings? I was thinking that since they work a little differently than the stock rubber ones they might do better with just plain grade 10.9 bolts rather than the reduced shaft bolts that were used originally. Also, it's nice to have new bolts on such critical parts rather than old, rusty 35 year old ones. I'm thinking the reduced diameter bolt design is designed to provide a more even torque potential.
Old 03-13-2023, 09:31 PM
  #2  
Supreme Member

iTrader: (1)
 
sofakingdom's Avatar
 
Join Date: Sep 2005
Posts: 26,115
Received 1,688 Likes on 1,283 Posts
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: Replacing control arm bolts

Not really.

The bolt clamps down on the sleeve, which is then held captive and immobile in the brackets. As long as the bushing sleeve fits tight on the bolt, there is no difference.

Now if your particular poly bushings have a larger ID sleeve, then...

None of that has anything to do with 10.9.Or old rusty. (beyond the obvious of course) If it fits, it works.

Never heard of "more even torque potential". Sounds like marketing mouth diarrhea to me.
The following 2 users liked this post by sofakingdom:
91banditt2 (03-20-2023), T.L. (03-13-2023)
Old 03-13-2023, 11:18 PM
  #3  
Member
Thread Starter
 
taguy16's Avatar
 
Join Date: Nov 2022
Posts: 193
Likes: 0
Received 8 Likes on 7 Posts
Re: Replacing control arm bolts

Here's something I found that explains what I was trying to describe about why bolt shanks are reduced when they are in tension: https://www.nord-lock.com/insights/b...f-bolt-shanks/ . Manufacturers used these kind of bolts for a reason.
Old 03-14-2023, 08:00 AM
  #4  
Supreme Member

iTrader: (1)
 
sofakingdom's Avatar
 
Join Date: Sep 2005
Posts: 26,115
Received 1,688 Likes on 1,283 Posts
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: Replacing control arm bolts

That's about bolts, not cap screws. Look alot the same but are not.
Old 03-14-2023, 09:11 PM
  #5  
Member

 
McLovin1181's Avatar
 
Join Date: Jan 2014
Posts: 341
Likes: 0
Received 101 Likes on 72 Posts
Re: Replacing control arm bolts

Zero issues replacing a-arm bolts.
stock bolts are all rusted and probably full of oxygen embrittlement.
I used fancy Zinc coated flange head bolts from BellMetric on my 92.
A-Arm bolts:2x:m12x1.75-110mm2x:m12x1.75-90mm

I got away with using 2x 100mm bolts with flange head lock nuts. But they were almost too short. I have maybe 1 thread past the nylon part of the nut

Unrelated pic of my old a-arm powder coated from leftover powder.
.
Old 03-20-2023, 09:02 AM
  #6  
Supreme Member

iTrader: (1)
 
91banditt2's Avatar
 
Join Date: Dec 2000
Location: Cincinnati,Ohio
Posts: 2,341
Received 151 Likes on 111 Posts
Car: 1991 BandittII Firebird
Engine: 5.7 HSR
Transmission: 700R4
Axle/Gears: 3.27 9 bolt
Re: Replacing control arm bolts

Replacing 30-40 y/o hardware is usually a good idea.
Old 03-20-2023, 09:07 AM
  #7  
Supreme Member

iTrader: (1)
 
91banditt2's Avatar
 
Join Date: Dec 2000
Location: Cincinnati,Ohio
Posts: 2,341
Received 151 Likes on 111 Posts
Car: 1991 BandittII Firebird
Engine: 5.7 HSR
Transmission: 700R4
Axle/Gears: 3.27 9 bolt
Re: Replacing control arm bolts

Originally Posted by McLovin1181
Zero issues replacing a-arm bolts.
stock bolts are all rusted and probably full of oxygen embrittlement.
I used fancy Zinc coated flange head bolts from BellMetric on my 92.
A-Arm bolts:2x:m12x1.75-110mm2x:m12x1.75-90mm

I got away with using 2x 100mm bolts with flange head lock nuts. But they were almost too short. I have maybe 1 thread past the nylon part of the nut

Unrelated pic of my old a-arm powder coated from leftover powder.
.
One of our customers is a third party inspector for the Nuclear industry, their standard regarding Nylocs was the end of the bolt had to be at least flush with the nylon portion of the nut, it could not be below flush with the nylon portion. The way I see it if the Nuclear power industry is good with it, so am I.
Old 03-20-2023, 12:13 PM
  #8  
Member
Thread Starter
 
taguy16's Avatar
 
Join Date: Nov 2022
Posts: 193
Likes: 0
Received 8 Likes on 7 Posts
Re: Replacing control arm bolts

Originally Posted by 91banditt2
One of our customers is a third party inspector for the Nuclear industry, their standard regarding Nylocs was the end of the bolt had to be at least flush with the nylon portion of the nut, it could not be below flush with the nylon portion. The way I see it if the Nuclear power industry is good with it, so am I.
Isn't the rule of thumb you're supposed to have at least two threads showing past the end of the nut when fully tightened? I'm not a big fan of nyloc nuts unless I'm using them on something that had them on to begin with. To me the all metal top lock nuts seem much more substantial and impossible to come loose over time.
Old 03-21-2023, 08:19 AM
  #9  
Supreme Member

iTrader: (1)
 
91banditt2's Avatar
 
Join Date: Dec 2000
Location: Cincinnati,Ohio
Posts: 2,341
Received 151 Likes on 111 Posts
Car: 1991 BandittII Firebird
Engine: 5.7 HSR
Transmission: 700R4
Axle/Gears: 3.27 9 bolt
Re: Replacing control arm bolts

Originally Posted by taguy16
Isn't the rule of thumb you're supposed to have at least two threads showing past the end of the nut when fully tightened? I'm not a big fan of nyloc nuts unless I'm using them on something that had them on to begin with. To me the all metal top lock nuts seem much more substantial and impossible to come loose over time.
I think in a lot of industries 2-3 threads past the nut is the rule of thumb though sometimes given space constraints of some mechanical designs that's not possible. Working in R&D for as long as I have this something that I bring up to our engineers quite often, some times it comes down to what's more important, this or that, "this" being a critical dimension that needs to be held to a certain tolerance or "that" being either using a jam nut with maybe 4 total threads and 2 threads past the nut or using a full size nyloc nut that may have 6-8 total threads with the end of the bolt flush with the nylon portion of the nut. Sometimes it's a case by case scenario.
Not saying that a nylon nut can't fail, because there's always the potential for and mass produced fastener to fail but in the 20+ years of using nylocs in the power distribution industry I've never witnessed first hand of a nyloc nut failing, maybe I'm just lucky that way
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
jstricker5133
Suspension and Chassis
1
10-18-2014 07:34 PM
The_Wraith
Transmissions and Drivetrain
4
02-28-2010 09:54 PM
Hoosier Bob
Suspension and Chassis
4
07-20-2005 02:53 PM
bubbareno
Suspension and Chassis
13
05-16-2004 06:17 PM
craig
Suspension and Chassis
4
11-14-2002 11:05 PM



Quick Reply: Replacing control arm bolts



All times are GMT -5. The time now is 07:10 AM.