Front Lower Control arm Bolts and Energy Suspension Polyurethane Bushings

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clemsparks

Not-quite-so-new-guy
Jul 26, 2009
33
7
8
Columbia MO
Hey folks, I think I have an issue with my front suspension and wanted to get some info/feedback/collaboration from folks here if possible. It's going to be a LONG post. The gist of it is that I think *possibly* the lower control arm bushings are meant for a 1/2" bolt and our G-bodies use a 12mm bolt (which is close to .030" smaller than 1/2").

I "recently" (less than 100 miles ago but the car was down for a couple of years) redid all the front suspension on the front of my '78 Malibu.

I purchased an Energy Suspension front control arm bushing kit (3.3156) and installed the lowers in stock control arms. I also replaced the lower control arm bolts (UPI-3013 from Summit) I ended up with tubular uppers (partly because I've been chasing a noise). I have new Moog ball joints, new wheel bearings/rotors, new sway bar end links, new KYB shocks and a new set of lowering springs.

I have a very disconcerting clunk/pop coming from the front end. I fairly sure it's coming from the driver side. I've had it apart and back together several times. I'm confident it is not the ball joints (I even changed the uppers because I suspected the aftermarket tall ball joints I got might be the culprit). I thought it might be the spring popping/clunking in the upper pocket or the lower control arm. I still think this *could* be the source of my noise, but I have removed and installed this new spring twice and the noise existed with the other set of springs I had in (will all the other new parts listed). To my knowledge, this noise did not exist BEFORE I rebuilt all the front suspension with new bushings/ball joints/shocks.

In my attempts to locate and eliminate the noise I have done the following:
Replaced my upper control arms with tubular speedway arms
replaced my upper ball joints
disconnected my front sway bar (removed an end link)
Removed the shock absorber to eliminate it as a possibility

When none of that worked, I removed the spring and articulated the arms/spindle through their range of motion by hand and could not replicate the noise.

Finally, I removed the lower control arm because I've had a suspicion the noise was coming from the lower control arm bushings/bolts.

When out of the car, I can put one of the lower control arm bolts through the lower control arm bushing and there is clearly slop/play. The 12mm bolt can be rattled around inside the steel sleeve of the bushing. However, if I grab a 1/2" bolt from the bolt bin and slide it into the bushing, it is a MUCH better fit. it seems appropriate. The frame mounts, of course, are set up for a 12mm bolt (a 1/2" bolt really doesn't fit through the holes in the frame for the control arm mounts.

I'm not sure what all is going on here.
It could be that somehow I got the wrong bushings in my kit (I kinda doubt this)
It could be that this is just the way energy suspension put the kit together from stuff they already made and the 1/2" ID sleeve over a 12mm bolt is "close enough" and everyone has this problem (I REALLY doubt this because I don't find any other threads about this out there)
It could be that it's affecting me because I scarred the surfaces of my control arm mounts on the frame a little bit while sawing the old bolts out (they were seized in typical rustbelt fashion). This is what I'm leaning toward. I'll try to post a photo. Maybe the inner sleeve of the bushing is not being "pinched" correctly to captivate it an allowing it to move some.

I submitted a message to energy suspension asking about this...I'm not sure if I'll get an answer back or not.

Does this ring a bell with anyone else here? Has anyone experienced this issue? Does anyone else have an energy suspension bushing not-installed-yet they could check to see the fit with their 12mm bolt and help me out?

My next step is to check the fit of a factory rubber bushing to the 12mm bolt.

If I didn't have any other input...I will probably opt to drill the chassis holes to accept a 1/2" bolt and reassemble it all with 1/2" bolts and hope for the best.

Thanks for your patience and I appreciate any EXPERIENCED conversation on this. I hate to say it, but you really have had to have done this work before to have valid input on the subject (ie: "the catalog says they'll fit so they must fit" is not productive conversation)
 
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pontiacgp

blank
Mar 31, 2006
29,270
20,391
113
Kitchener, Ontario
I believe if you look at the instructions for the control arm bushings it tells you you have to drill to use 1/2" bolts

"GM G-Body, must drill frame to 1/2" and utilize 1/2" bolts "
 
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565bbchevy

Geezer
Aug 8, 2011
9,590
12,612
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Michigan
I also recently rebuilt the entire suspension on my Regal project and I drilled mine to 1/2" because the bushings were sized for them and I didn't want any slop, only drove the Regal to get an alignment but didn't hear any noises.
 
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pagrunt

Geezer
Sep 14, 2014
9,122
15,255
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Elderton, Pa
I have Energy Suspension bushing in the uppers & lowers that I put in about five years ago. I didn't see anything about 1/2" bolts in the instructions & reused the originals. Everything felt snug when I put the lowers on. Keep in mind my frame hasn't hit the road yet or have full weight on it.
 

clemsparks

Not-quite-so-new-guy
Jul 26, 2009
33
7
8
Columbia MO
I believe if you look at the instructions for the control arm bushings it tells you you have to drill to use 1/2" bolts

"GM G-Body, must drill frame to 1/2" and utilize 1/2" bolts "

Thanks. I looked on their site for instructions but the "generic" instruction sheet that comes up (even when looking up these specific bushings and kits that contain them) is actually for upper control arms/shafts. I'll comb through my file folder again to try to confirm (Edit, I don't have my hard-copy of instructions for these bushings anymore). I was thinking maybe I vaguely remembered reading that at some point...but not really sure...and not sure why I didn't DO that if I had read that (I'm one who actually reads instructions...usually...and follows them)

I also recently rebuilt the entire suspension on my Regal project and I drilled mine to 1/2" because the bushings were sized for them and I didn't want any slop, only drove the Regal to get an alignment but didn't hear any noises.

Glad to hear your first-hand experience matches up with what my intuition told me. That's helpful...thanks!

7/16 bolt= 1/2 hole
1/2 bolt = 9/16 hole

Maybe on a tractor, but not on my suspension. Sorry, but I disagree. We're talking about the double-shear pivot point on a suspension control arm here, not a non-critical bracket. But I'm also the guy who buys 5/16" washers for 3/8" bolts because the fit is more "appropriate".

One issue is that the polyurethane bushings work differently than a rubber bushing. The rubber bushing twists. The polyurethane actually slides. So when we put in a different bushing that has a different design function than original, it changes the way we have to look at it as well.
 
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shoedoos

Master Mechanic
Jul 3, 2012
406
403
63
just been through this myself....open up the holes and a 1/2" bolt is the answer. Make sure you use bolts with an unthreaded shank so they don't chew out the frame. I used an adjustable reamer to open the holes up....much easier to get in there with a reamer.
 

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Macguyver

SOUTHSIDE MACHINE PERFORMANCE
GBodyForum Sponsor
Mar 21, 2017
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Drill frame to 1/2". Must use 1/2" bolts on the lower bushings. We sell these or hit up a hardware store. ($16 shipped)
 
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clemsparks

Not-quite-so-new-guy
Jul 26, 2009
33
7
8
Columbia MO
Much thanks folks! Glad to know I'm not crazy or the only one to have this issue. Just wish I'd figured it out a year ago. And I was wondering how I was going to get a drill in there. I'll check out reamers, thanks!
 

565bbchevy

Geezer
Aug 8, 2011
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