Strut Rod Bushings

[JGC403]

Its been awhile since I have been on here, so if this has been talked about before point me to the thread. Been working on other projects and finally getting back to my 1968 Barracuda.

I have a '68 Barracuda and a '76 Duster. I have been collecting parts for the past couple of years for both. Right now I am putting a K frame together for the Barracuda so I needed strut rod bushings. I have a set of MOOG K7068 for the Duster and I bought a set of MevoTech MK7040 for the Barracuda. I got them off rockauto when the K7068 were still available. Anyways I see that there are polyurethane bushings available Energy Suspension 57109G and its listed for both the '68 and the same set for the '76. Well that doesn't seem right. The early fine thread strut rod bushing is a little shorter than the later course thread bushing. So the Energy Suspension bushing can't be used for both styles strut rod. The Energy Suspension bushing use a metal sleeve inside. The metal sleeve is the same height as the K7068 bushings would be. So it looks like the 57109g bushings would be to tall to work with the early strut rods? I have a couple of pictures below showing the height differences between all of the bushings. The 57109g is taller than the K7068, but the bushings are tapered so I guess it will compress to the height of the steel sleeve that goes inside the 57109g. So should I cut the steel sleeve down to the correct height for the early style strut rods and shave off some of the bushing?

First picture below Left Moog K7068, middle Energy Suspension 57109G, Right MevoTech MK7040
Second picture is Left Moog K7068, Right MevoTech MK7040

 

[roadrunnerh]

I'm rebuilding the front suspension on my Scamp, and I also wondered this as well, although not with the MevoTech in the mix.
How can the ES part work for both?

 

[72bluNblu]

I'm rebuilding the front suspension on my Scamp, and I also wondered this as well, although not with the MevoTech in the mix.
How can the ES part work for both?

Easy, it doesn’t.

You can’t use the same bushing for the early and late style strut rods. @autoxcuda covered a fix by cutting down the poly bushings to fit properly on an early car

Cutting strut rod bushings for correct geometry?

But really the poly bushings at the strut rod location aren’t a great idea. The strut rod has to move in two different planes. In the vertical plane where the strut rod tracks the LCA, you don’t want the bushing to be stiff. Adding a stiff bushing puts more resistance into the suspension travel, which isn’t what you want. In the horizontal plane you do want the bushing at the strut rod to be stiff, to prevent the LCA from flexing forward and backward with braking and acceleration. So the poly works good for that, where the rubber allows a bunch of slop that causes geometry changes.

This is why adjustable strut rods work well. They allow the strut rod to track the LCA up and down with very little resistance, but keep the LCA from moving forward and backward.

 

[JGC403]

Thanks. So I just need to trim the poly down. I'm going to switch to an adjustable strut rod eventually. I just want to build it stock for now then see how changes affect it.

Easy, it doesn’t.

You can’t use the same bushing for the early and late style strut rods. @autoxcuda covered a fix by cutting down the poly bushings to fit properly on an early car

Cutting strut rod bushings for correct geometry?

But really the poly bushings at the strut rod location aren’t a great idea. The strut rod has to move in two different planes. In the vertical plane where the strut rod tracks the LCA, you don’t want the bushing to be stiff. Adding a stiff bushing puts more resistance into the suspension travel, which isn’t what you want. In the horizontal plane you do want the bushing at the strut rod to be stiff, to prevent the LCA from flexing forward and backward with braking and acceleration. So the poly works good for that, where the rubber allows a bunch of slop that causes geometry changes.

This is why adjustable strut rods work well. They allow the strut rod to track the LCA up and down with very little resistance, but keep the LCA from moving forward and backward.

 

[JGC403]

I'm rebuilding the front suspension on my Scamp, and I also wondered this as well, although not with the MevoTech in the mix.
How can the ES part work for both?

If you are reusing your stock course thread strut rods for a '75 Scamp, then you should be fine with the poly bushing if you want to go that route.