cfair

On my '66 Starfire I've got an intermittent clunk in my lower control arms or front suspension somewhere. I hear it mostly when I back out of my sloped driveway and the suspension is at an extreme angle or when I go from forward to reverse sometimes.

The rubber bushings look generally pretty good to me, with 1 one just beginning to crack but others look solid. It could be failing invisibly, but I'm trying to chase down anything beyond that just in case. Lower control A-arms from these 66 big cars have failed me before, so I watch them like a hawk, and listen like one too. Any clunks make me nervous.

I was under the car today and got some shots. Could I get your opinions on how these lower control arm (LCA) or lower A-arm bushings and mounts look to you?

Some of the frame mounting ears look slightly bent to me, but I'm not an expert so I can't be too sure where the A-arm movement "clunk" is coming from. I would expect the mounts to be straight, not bowed out, since any bowing out mignt allow front/rear movement of the A-arm in motion.

If the mounts are bent enough to contribute to a clunk, is it a dumb idea to press them back into shape? I can see where bending them back into shape might stress the metal too much and cause a crack (+eventual failure), or maybe it's the right fix.

Here's the left front lower control arm bushing:

Does this bushing look o.k. to you? Is the gap between bushing and mounting ear too wide? Nothing obviously bad to me, but I'm not sure if the gap on the right would allow forward /back movement.

Here's the left rear LCA bushing, aka driver's side rear.

Could this bend be causing an intermittent suspencion clunk?

Here's another view of the driver's side rear LCA bushing.

Bang this bend back into shape? Or bad idea?

Right front LCA. I know there's cracking here, but it's just beginning. A possible clunk-source, to be sure, but I'm wondering about the other 3 corners

Cracks like this can cause noise, but on this one, I think not yet. But I could be just plain wrong.

Here's the right rear LCA bushing. The gap between bushing and the mounting ear seems a bit wide to me, but I'm no expert to be sure.

Could this bushing-to-mounting ear gap allow noisy suspension front/rear movement?

I've had 2 mechanics chasing this intermittently for about 6 months and no real progress yet.

Eventually I'll have to do all the control arm bushings, but if I can solve the clunk short of that, it's a win since the rubber is not bad yet. Plus if there's a problem that is _not_ the bushings, all that money spent replacing them will still leave me clunking around.

Thanks in advance for your views. If you see other problems like the wrong bushings or reversed bushings or other suspicious noise-sources, please let me know.

Cheers
Chris

oldcutlass

The bent control arm bracket could cause premature wear on the bushing and straightening it is not an issue. The one with the gap in your last picture is a concern because the arm looks like it can slide back and forth on the mounting bolt.

joe_padavano

The bent tabs on the frame brackets are not a concern so long as the bolts in the bushings are properly torqued. There's a heavy-wall sleeve inside the bushing. The bolt is supposed to clamp that sleeve between the ears on the frame bracket. Distortion at the open end of the ears isn't going to do anything, so long as you can fully clamp the ears against the bushing sleeve. Likely someone used a floor jack in the wrong place.

The gap is problematic. As I said, the ears need to fully clamp against the sleeve in the bushing (and be sure to torque those bolts with the suspension at ride height). If you cannot tighten the bolts sufficiently to close the gap, you have the wrong length bolts.

cfair

Joe,
Guessing you’ll know what the bolt length should be. I’m not sure I’ve ever seen any bolt length citation in the CSM or assembly manual.

What length should they be to be correct?

I can check the CSM and assembly manual for bolt/nut torque specs, but if you happen to know them off the top of your head, I’d be very grateful if you’d share.

Thanks to both of you for your guidance. This is the sort of knowledge you have that my local guys would have to really chase down to get right. Invaluable

Cheers
cf

cfair

Just looked up torque values in my 1966 Olds Inspector’s guide.

Do these torque values look correct to you all for a 1966 Starfire / 88 / 98 (not Cutlass) with the weight of the vehicle on the wheels?

Lower Control Arm (LCA) bolts 65-85 foot lbsUpper Control Arm (UCA) shaft to frame 95-115 foot lbs

Upper Control Arm (UCA) bushing to shaft 50-60 foot lbs
If these values are correct, my next step would be crawling around underneath and retorquing the LCA bolts as a start. I’m not too worried about upper control arms, but you never know.

One thing I noticed in a similar thread was some of the GM factory advice was torque to the correct values and recheck after 50 miles or so. I’m fairly certain after torquing to whatever values were used, nothing was ever retorqued after some mileage like that.

Advice most appreciated. I can handle retorqueing some bolts, but I usually stay away from spring loaded safety related stuff.

Many thanks in advance
Chris

Fun71

Keep in mind that the bolts need to be torqued with the weight of the vehicle on the suspension.