Problems with poly bushings in LCA's!!!

[71Scamper]

so I just finished rebuilding the entire front end of my 71 Scamp. I was going to just replace the lower control arm bushings but I noticed my left pivot pin was bent. So I ended up ordering a poly bushing and lube-able pin kit from Hotchkis. When I was installing the torsion bar retaining clips I noticed the left pin had backed out of the bushing about a quarter inch and the torsion bar wouldn't seat all the way in like the passengers side. I used a block of wood and hammered the pin back in. I put some tension on the bars and set it on the ground. after lifting and dropping the car half a dozen times trying to get ride height semi close, I noticed it had backed out again.

What the hell should I do? I'm thinking of making a couple hex spacers to fill the remaining space in the torsion bar bores and using a snap ring instead of the cheap wire retainer.

 

[replicaracer43]

Stock lower control arm bushings are what you want, those poly bushing wont locate the lower control arm properly, and if you corner hard with them, I find that they tend to "pound out" of shape... I use stock lowers even for oval track use......

 

[SGBARRACUDA]

I had the same problem with my poly lowers on my 69. I went ahead and used them but I will be replacing them in the near future. Far as I'm concerned they suck and I'll never use them again. They stayed a little bit out and they do seem like they pound out of shape when cornering and make noise.

 

[Oldmanmopar]

You have the wrong strut rods for the bushings you used. I have many come here with that same problem. two piece strut bushings go with coarse thread bars. One piece bushings with fine thread bars.

These are pics of the different a-body bars. 73 up is the coarse thread and are different length for the two piece bushing with spacer.

The early a-body bars do not take a spacer

 

[SGBARRACUDA]

You have the wrong strut rods for the bushings you used. I have many come here with that same problem. two piece strut bushings go with coarse thread bars. One piece bushings with fine thread bars.

These are pics of the different a-body bars. 73 up is the coarse thread and are different length for the two piece bushing with spacer.

The early a-body bars do not take a spacer

I think he was talking about LCA poly bushings.

 

[71Scamper]

I think he was talking about LCA poly bushings.

I was talking about the lower control arm bushings. I am also running a set of RMS adjustable strut rods.

Doing some more research I came across a thread on here with someone that had the same problem. He was told that its the strut rods pushing the control arm away from the k frame. When I set the suspension and the strut rods, I did do it with the suspension hanging, and would make sense that it would push it out when the suspension settles into the normal ride height due to the arc the strut rod makes. I'll have to set it with the car fully back together and properly aligned.

 

[Oldmanmopar]

I think he was talking about LCA poly bushings.

Yes I know but this could be the reason that the lca's get pushed back off the pin. The strut rod is wrong holding the lca back. See it all the time. With standard lca bushings you won't see this because they are molded. It would just throw the caster adjustment way out and then guys put off set eccentric upper bushings in to compensate.

To use a poly kit you better know what parts you have standard and what your buying.

 

[SGBARRACUDA]

I will be using the OEM lower bushings from now on. Much less headache.

 

[Dana]

right on oldmanmopar. If you rgonna use poly strut rod bushings,you either need shorter strut rods (firm feel) or adjustables. Or some guys grind a little of the poly bushings

 

[RustyRatRod]

You have the wrong strut rods for the bushings you used. I have many come here with that same problem. two piece strut bushings go with coarse thread bars. One piece bushings with fine thread bars.

These are pics of the different a-body bars. 73 up is the coarse thread and are different length for the two piece bushing with spacer.

The early a-body bars do not take a spacer

Exactly. They don't call him Oldmanmopar for nuthin.

 

[AdamR]

I had the same issue when I tried them. Stock rubber ones solved the problem.

 

[Oldmanmopar]

The lower lca bushing should not be used to hold the control arm in place. When tightening the strut rod the lca should be up against the K with out the nut installed. Then The pin nut on the lca should be tightened as well as the upper eccentric bolts when the car is on the ground. at its ride height. This will prevent the bushings from tearing out of the sleeves from over extending the engineered travel of the arm bushings.

The ride height is determine by measurements subtracted on the lca an ball joint as per the service manual.. Once you determine the proper height location and tighten the pin nut and eccentric bolts then you can change the ride height to what ever you want.

Failure to follow this will destroy the bushings and the car will wander..

As far as off set bushing for radial tires that is BS. If it doesn't align with factory parts you have other issues. I installed radials on many cars that were bias and never had any alignment issues. Usually if the front won't come in on a rack it is due to improper ride height Front or rear.

Notice the ride height of my car. It has skinny radials up front and 14.5 wide slicks on the rear. I kept the factory ride heights front and rear . The car runs straight as an arrow. I keep a 1 1/2 turns in the left bar for the street.. This levels front with the rear tires on the ground. Take it out for the track and car leans to the left due to SS springs.

Front bars should always be adjusted with the rear jacked just off the ground in the center so it tricycles. This will properly level the front bars without interference from the leaf difference. Just what I have been doing for years . Use the info or not . I am sure others will chime in with there opinions.

 

[72bluNblu]

There's no problem with the poly LCA bushings, you just have to use the strut rods to locate the LCA, which is what they're intended for anyway. Easiest way to do that is with adjustable strut rods, so that you can adjust the length until the LCA is pulled up on the pin, stopping just before you start to get bind.

The stock rubber bushings aren't intended to locate the pins OR the LCA's either, that's still the strut rods job. The rubber in those bushings is just bonded to the shell of the bushing and the inner sleeve, and that's all the keeps anything from moving around. That bonding doesn't amount to much strength, and fails anyway on pretty much all of them over time. Or fails immediately if not installed properly by torquing everything at ride height. Plus, there's no guarantee that the original strut rods actually locate the LCA in the proper place. Factory tolerances, 40+ years of use, and aftermarket strut rod bushings often mean the LCA isn't located properly by the stock strut rods.

It does take longer to set up the adjustable strut rods, but it gives you the ability to actually make sure everything is set up right, instead of just bolting on the stock stuff and wondering why the alignment isn't right.

And at the OP- Did you inspect the left LCA for damage around the bushing? Or the K frame for damage at the pivot tube? Those pivot pins are not easy to bend, so I would be concerned that either the K frame mount or LCA was damaged as well. Especially the K frame, as that's a fairly common problem.

***Edit***

Guess oldmanmopar and I were typing at the same time!

 

[Commando66]

Had the same problem when installing poly bushings on my Barracuda. Turned out that there was too much grease in the bushing. Cleaned out most of the grease and the pin seated all the way.

 

[71Scamper]

oldmanmopar - I understand everything your telling me. I know you didn't know this but I am a technician and for the past couple years been teaching it to youngsters in high school. I know all too well about tightening everything up with the suspension loaded at proper ride height. That doesn't apply to this car as I am running adjustable uppers, poly lowers, and adjustable strut rods.

72bluNblu - I have swapped to a v8 K-frame and I had checked both lowers after I realized the pin was bent. Both arms check out to be the same.


I redid this on the alignment rack and got the bushing all the way on the pin. then adjusted the adjustable strut rods til there was about a 1/4 inch gap between the bar and the LCA. I then tightened down the bolt to suck the LCA forward that small amount to keep a little forward pressure on it. Also, for peace of mind I took over-sized washers and cut them into a hex that fit perfect in the rear torsion bar anchors. I used them to take up any space between the wire clip and the T-bars. I also installed heavy duty snap rings and chucked the little wire retainers. So far so good!

 

[Oldmanmopar]

If you knew what was wrong and had it handled why the thread?

 

[71Scamper]

If you knew what was wrong and had it handled why the thread?

At first I didn't understand why the arm kept wanting to push off the pin. I figured with the tension from the T-bar adjusters they would keep the arm in place and not allow it to slide back. Then I realized after I posted the thread, that the arc from the torsion bars was forcing the control arm back. But even still I wanted to be sure that I wasn't missing something here like additional parts. But thanks for the help!