Lower control arm bushings

[Paul G]

Getting ready to replace the lower control arm bushings. Is there a difference/preference between brands of replacement bushings? Lots of places list them. None are sold in Poly any more. LCA bushings are all rubber, at least I have been told by calling Moog. Different retailers list the Moog K791, K791A, K791B. Anyone know what the difference is?     

[red79]

Some shops still sell poly or nylon lower bushings, but they're tricky to use successfully and most recommend adjustable strut rods to pair with them. Even with adjustable struts, you can end up with squeaks, extra wear and tear on the system, and weird wearing issues if the lca starts backing off the bushing. I'd stick to rubber if I had it to do over again 

[Nacho-RT74]

I got dissapointed with poly lowers. LCA began to be out of its place... maybe needed to be matched with Poly strut rods bushings too? dunno.

next will be lower rubber and upper poly ( which are still rubber )

about original question... Commercial brands only make rubber... poly products are performance aftermarket brands like those Summit offers ( Energy Suspension and those )

[mally69]

Just last year I put all new poly lower control arm bushings in my 69. I was pleased with them. Honestly can't remember what brand they are off hand but the company had a large add in a mopar muscle magazine.

[Paul G]

What seems odd, the rubber bushings are molded to the sleeves, which keeps the control arm and the shaft held together.

The poly bushings are just pressed in to the control arm, and the shaft is pressed in to the poly bushing. Nothing holding the shaft and the control arm firmly together, or preventing them from sliding apart.

[myk]

That doesn't sound very reassuring...

[Paul G]

Went for a test drive this morning, Over the past week I installed Prothane poly bushings, lower control arms only, the uppers are rubber and still in decent shape, same for the strut rod bushings. 

We modified the strut rods before they went back on the car. I got two grade 8, 3/16" thick washers from Ace Hardware. Washers that are big enough to slide over the frame end of the strut rod shaft. The strut rod has a shoulder machined in it for the bushing backing plate to seat against. On the frame end of the strut rod, I wanted to move the shoulder back that 3/16". Measure back on the shoulder 3/16" (thickness of the washer). Then remove the material from the shoulder, hack saw and file, making the shoulder actually 3/16" further back. The bushing backing plate is now 3/16" back, against the new shoulder. When the strut rod is reassembled, the new washer is used behind the nut on the frame end to take up the distance you cut the shoulder back.

This will move the lower control arm 3/16" forward, giving you a little more caster angle. Neat trick. 

The test drive went very well. The car tracks straight, Handling is very good. I dont notice much difference in the ride quality yet. It was all smooth road. Got in to a big empty lot and did some hard cornering, left and right. Car still tracked straight afterwards. On the way home I did a quick sprint to 100 MPH on a back road. So much smoother and more stable at high speeds than it was before by far. Probably the worn out bushings I replaced were causing a lot of bad vibes in the front end. so far nothing negative to say about the poly bushings. Time will tell.