Strut rod and polyurethane bushings issue?? 74 Dart

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George Lawicki

George Lawicki

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Hey guys,
I am in the process of rebuilding my entire front suspension. I am using all rubber bushings: however, the MOOG k7068 bushings are currently not available for the strut rods so I am thinking for substituting them with polyurethane. I have read that this will affect the caster come time to align it??? So question is, anyone with knowledge about this or will I be able to use poly bushings??
 
You may have to use the urethane. I find nothing else anywhere. ANYWHERE.
 
Don’t do it. The polyurethane strut rod bushings aren’t the right thickness. Even if they were, polyurethane is not the right material for the OE type strut rods. The problem is they move in multiple directions. In controlling the forward and backward motion of the LCA (like with braking or acceleration), the harder poly material would be good. It keeps the LCA from flexing around as much and controls the caster changes better.

The problem is the OE strut rod bushings also have to flex to allow the strut rod to angle up and down to travel with the LCA as the suspension moves. In that direction, the poly is terrible. The harder material creates more resistance to the travel of the LCA, more binding in the suspension. Which is exactly what you don’t want.

You’d be better off with adjustable strut rods, they limit forward and backward motion but freely allow up and down travel. And you can set them to the proper length for your car so you can reduce binding.

The Moog 7068’s have had supply problems for over a year now, I’ve had orders cancelled at Summit, Jess, RockAuto, Amazon etc. and they show out of stock or back ordered at all of those suppliers and more.

If you really don’t want adjustable strut rods, you might have to get a set of 67-72 strut rods (fine threads), as the one piece strut rod bushings are available but only work with the early strut rods. Personally, that’s a waste of money IMO, I’d just buy some QA1 adjustable strut rods and enjoy the upgrade.
 
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I have a set of moog bushings, two piece design, that are just sitting because I went with adjustable (which means I have a good used set of fine thread strut rods too).
I ordered them for my 72 dart, but I'm not convinced they're not for the later design.
I can get the part number tomorrow or Sunday when I'm back in the barn again.
PM me.
 
72bluNblu said:
Don’t do it. The polyurethane strut rod bushings aren’t the right thickness. Even if they were, polyurethane is not the right material for the OE type strut rods. The problem is they move in multiple directions. In controlling the forward and backward motion of the LCA (like with braking or acceleration), the harder poly material would be good. It keeps the LCA from flexing around as much and controls the caster changes better.

The problem is the OE strut rod bushings also have to flex to allow the strut rod to angle up and down to travel with the LCA as the suspension moves. In that direction, the poly is terrible. The harder material creates more resistance to the travel of the LCA, more binding in the suspension. Which is exactly what you don’t want.

You’d be better off with adjustable strut rods, they limit forward and backward motion but freely allow up and down travel. And you can set them to the proper length for your car so you can reduce binding.

The Moog 7068’s have had supply problems for over a year now, I’ve had orders cancelled at Summit, Jess, RockAuto, Amazon etc. and they show out of stock or back ordered at all of those suppliers and more.

If you really don’t want adjustable strut rods, you might have to get a set of 67-72 strut rods (fine threads), as the one piece strut rod bushings are available but only work with the early strut rods. Personally, that’s a waste of money IMO, I’d just buy some QA1 adjustable strut rods and enjoy the upgrade.
Click to expand...


I agree with this. Buy once, cry once. Once you go adjustable strut rods you never go back.
 
Ok guys,

Looks like Iam going to go with the adjustable strut rods..So QA1 has these..
64-76 Chrysler A-Body QA1 Dynamic Strut Bars 52311
And they use no bushings???? just bolt in??

_p_2_p23383.jpg


How will these affect the ride???
 
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George Lawicki said:
Ok guys,

Looks like Iam going to go with the adjustable strut rods..So QA1 has these..
64-76 Chrysler A-Body QA1 Dynamic Strut Bars 52311
And they use no bushings???? just bolt in??

View attachment 1715741066

How will these affect the ride???
Click to expand...


They bolt in. Just follow the directions. There can’t be any binding. If there is the bar isn’t adjusted correctly.

72nublu can add more, but the ride should get better.

If you are really into spending money now would be the time to use poly or delrin bushings to make things really solid.

I’m not a fan of rubber bushings. Especially the stuff I’ve seen lately.
 
George Lawicki said:
Ok guys,

Looks like Iam going to go with the adjustable strut rods..So QA1 has these..
64-76 Chrysler A-Body QA1 Dynamic Strut Bars 52311
And they use no bushings???? just bolt in??

View attachment 1715741066

How will these affect the ride???
Click to expand...

it’s a metal to metal connection. To some amount there will be more NVH (noise, vibration, harshness).

not a good idea in a Cadillac.

but are you adding sway bars, bigger torsion bars, and other handling improvements? Is this a high performance car with headers, cam, etc... basically it makes more noise than a 318-2bbl ?? If so, I doubt you’d hear or feel much difference.

everyone’s sensitivity and expectations are slightly different. So tough to predict your perception.

I ran poly strut bushing for 17 years. But I cut and shaved the rear bushing 3/8” and the center sleeve. I got 3-4 degrees caster with moog 7103 offset UCA rubber bushings.
 
yellow rose said:
They bolt in. Just follow the directions. There can’t be any binding. If there is the bar isn’t adjusted correctly.

72nublu can add more, but the ride should get better.

If you are really into spending money now would be the time to use poly or delrin bushings to make things really solid.

I’m not a fan of rubber bushings. Especially the stuff I’ve seen lately.
Click to expand...
I agree alot of stuff is garbage out there however I already bought my suspension parts and bushings. When time comes to redo the suspension I can decide how I want to go. I worry about using poly because of ride. I dont want a stiff ride especially here in Cleveland.
 
autoxcuda said:
it’s a metal to metal connection. To some amount there will be more NVH (noise, vibration, harshness).

not a good idea in a Cadillac.

but are you adding sway bars, bigger torsion bars, and other handling improvements? Is this a high performance car with headers, cam, etc... basically it makes more noise than a 318-2bbl ?? If so, I doubt you’d hear or feel much difference.

everyone’s sensitivity and expectations are slightly different. So tough to predict your perception.

I ran poly strut bushing for 17 years. But I cut and shaved the rear bushing 3/8” and the center sleeve. I got 3-4 degrees caster with moog 7103 offset UCA rubber bushings.
Click to expand...
I do have a front swaybar that will be installed. I also bought new torsion bars 1.03 from pst . Rest of suspension parts are new but stock with rubber bushings . The car is a /6 auto with the intentions of a 408 in the future. The goal is a drivable street car not just on weekends or car shows and some light track passes.
 
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