LCA's worn out??

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CordobaDart

CordobaDart

318 SLANTMAN
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Hi, I am still pretty new to posting on FABO, so please bear with me(haven't figured out how to post pictures here yet).

A couple months ago, I removed the lower control arms in my 73 Dart Sport as they were moving around so much I could not even get the toe anywhere close to correct. After removing the old bushings I noticed that the entire center section in the arm(where the bushing goes in and what the torsion bar goes in), this whole center assembly felt very loose. Seemed to me like the the control arm opening was worn outward from use. Unsure, I put in new bushings and bolted everything back together.

Now the shaft with the torsion bar stays in place, but the control arm visibly moves inward and outward when I watch it as someone else tips the wheel in and out. I still cannot even get the toe set. I recently replaced the idler arm, and all other suspension components seem to be tight.

I am fearing that I will need different lower control arms? :wack:
Anyone heard of this before?
 
It does sound like your LCA's are worn out. Some movement is normal, but the visible movement you describe, and the inability to set the toe, suggests that the LCA's may be worn to the point of needing to be replaced.

However, the strut rods are also there to control some of that movement. How are your strut rod bushings? If they're also worn out, replacing them might help control the LCA's better.

You could also make the move to adjustable strut rods, which would allow you to adjust the tension on the LCA's a little (too much will cause binding). Now, if the LCA's are worn out, they're worn out and should be replaced, but being able to adjust the strut rods does give you some more options when setting the alignment.
 
Thanks for the quick response, I thought about what you said, and it makes sense to me. I searched adjustable strut rods and one of my first results was this page: http://www.firmfeel.com/adjstrut.htm

*Note I did put in polyurethane lca bushings from Prothane Motion, so this seems to sound like it applies directly to my predicament.

Quote from the above linked page: [FONT=Arial Black, Gadget, sans-serif]"Urethane strut bushings are based on the '66-'72 B-body and '70-'74 E-body style strut bushing dimensions. This strut bushing happens to be thicker than most all other strut bushing combos out there. Approx. 3/8 inch thicker than the '63-'72 A-body bushing. This pushes the lower control back, putting the LCA bushing in a slight bind but more importantly losing what little positive caster it had in the first place,( these cars only have about 1 degree of positive caster). We built these adjustable struts to properly locate the LCA (lower control arm). If you are running urethane or nylon LCA bushings and urethane strut bushings your strut length is now more critical to insure the LCA doesn't slip back or forward on the pivot pin. Otherwise your LCA inner pivot will be " floating," so the front end alignment (toe setting) will not stay put."
[/FONT]
 
This is a strange one. Odd that it is both LCAs. Suggest you put car on stands and crawl under it again. Disconnect the front anti-say bar, if the car has one' so that it does not disguise what is going on under there. Focus on the LCA bushing while some one wiggles the wheel back and forth. Look for wiggling around the bushing. Bear in mind that you're probably looking for a minute amount of movement at the LCA. The deflection gets magnified as you go towards the wheel.

If the bushing wiggles in the LCA, the problem may well be worn or bent bushing "race" in the control arm. This is not maintainable. Some may say that the bushing can be tack welded in. IMO, this is not a very sound solution fuel in part by my limited welding skills. Replace LCAs.

If the bushing does not wiggle in the LCA, the problem is probably between the bushing and the LCA shaft. Either the shaft is worn badly or the the center of the LCA bushing is too large.

If you need to replace the LCAs, be sure to specify whether or not you have an anti-sway bar on the car. You can put LCAs with tabs on them now and add the bar later.
 
Oh, I did look at my strut bushings, they seem fine. I like the idea of adjustable strut rods, but they seem pretty pricey, going to shop around and see what my options are. I am visualizing how slightly too long strut rods could let both caster and toe change if the rods are not holding the arms forward enough, makes more sense all the time. Any input on what works and/or what is the best "bang for the buck" is greatly appreciated.

And thanks again.

I will have to post what I figure out on here when it's fixed. Now to fire up the wood burner in the garage. Yes, it is 41 degrees here in southern MN right now. Tuesday we had a high around 75...
 
With the poly LCA bushings the strut rod length is a lot more important. Unlike the original bushings, the bushing can slide on the pivot pin, or even in and out of the bushing shell if the pin isn't tight enough.

I'd take a good look at how everything is moving. Jack the car up, remove the shocks and back off the torsion bar adjusters. That should allow you to raise and lower the suspension pretty easily and look for movement. Also, check to make sure your LCA pivot pins are tight. That nut on the front of the pin is supposed to get torqued to 100 ft/lbs with poly bushings.

As far as the adjustable strut rods go, a member here (Badart) has a shop and makes them. His site is here

http://www.dillingerchassis.com/

I like Firm Feel, but their prices can be a little high. Badart makes awesome stuff for VERY reasonable prices.
 
@ 2 Darts: The car currently has no sway bar, but I want to install one. A sway bar would help tie everything together in my thinking.

The poly bushings fit very good. Nice and tight fit when used the press to put them in. The whole center section of the lca with the arm where the torsion bar adjustment bolt contacts the arm, the torsion bar goes in, and the bolt goes through the k member is the movement that I am talking about. The K-member is not worn out and the bolt is good and tight. At this point, the torsion bar and the center part of the lca that it goes into stays put. The lca itself moves slightly on this center part.(Do not know proper name of this..)

This car seems to have had many iterations over it's unknown life. Started life as a /6 car. Now has a 318. The front suspension of this car has a soft feel, probably has the factory /6 torsion bars, and raises considerably during acceleration. Maybe this excessive up and down movement could have led to wearing the lca's where metal to metal contact is occurring?

Note that the front shocks are weak and will be replaced soon. I might go ahead and replace the upper control arm bushings as long as I have it all apart again as well.

Yea, if I replace the lca's I will opt for sway bar ones.
 
You NEED to watch this video.

[ame="http://www.youtube.com/watch?v=Nwes-SP8u4w&feature=plcp"]Control arm repair - YouTube[/ame]
 
Jim Lusk said:
You NEED to watch this video.
Click to expand...

I DID! :blob: THANKS for this link. This is exactly the problem my LCA's were showing. I did look at some different ones we had off of cars at the shop I work at, a set from a 71 Cuda and a 69 Charger, both were tight and had barely any play, so I know something is wrong with the ones on my Dart for sure now. The good news, I just happen to be a decent welder. The bad news, I gotta take it all apart again. Oh well, I will post some videos of the repairs as well when I get it apart.

And if anyone is interested, here is a short video of a fellow Mopar friend and myself taking my offending Dart for a little drive shortly after I got it. (I have been repairing broken, wrong, and plain worn out stuff on this car ever since. Learned tons already.) I really hope to have this car driving top notch soon, seems like there is always some other project that takes priority.

Well, here is a link- [ame="http://www.youtube.com/watch?v=5z0RuMnx6FY&list=UU8kcW5O5Bfc-87zOfuOP_4w&index=4&feature=plcp"]Dart Sport 318 Fun Run - YouTube[/ame]
 

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Nice car. Glad I could help. This is a problem that has had very little exposure over the years, but I discovered the slop on a pair of arm I was rebuilding a few years ago.
 
Just a quick update, I got a new in box rear sway bar from a friend for 75 bucks, he got it at a swap meet recently and didn't need it anymore. Anyways, I installed the kit Addco 919, it fit just fine, had to drill 4 holes into the frame rails to mount it.

Anyways, I've been busy with family stuff and now deer hunting season, but in the next few weekends I will take the front end back apart to start the repairs of the lower control arms and new upper bushings as well.

I will be installing a front sway bar as well. Going to buy either the Hellwig 55905 or Addco 596.

I will take pictures of my lower control arms to show the play in them before and hopefully after when repaired.
 
CordobaDart said:
Just a quick update, I got a new in box rear sway bar from a friend for 75 bucks, he got it at a swap meet recently and didn't need it anymore. Anyways, I installed the kit Addco 919, it fit just fine, had to drill 4 holes into the frame rails to mount it.

Anyways, I've been busy with family stuff and now deer hunting season, but in the next few weekends I will take the front end back apart to start the repairs of the lower control arms and new upper bushings as well.

I will be installing a front sway bar as well. Going to buy either the Hellwig 55905 or Addco 596.

I will take pictures of my lower control arms to show the play in them before and hopefully after when repaired.
Click to expand...


Be careful driving with just a rear sway bar.

Actually, for safety, just disconnect the rear bar until you get one for the front.
 
Those poly LCA bushings scare me. It sounds like Firm Feel says that the strut rod must pull it tightly forward to keep it from slopping around fwd-aft. I guess I don't see how the strut rod can do that well since it pulls at an angle and can pivot.

I watched the LCA video but couldn't hear the audio. I don't think the radial play shown matters since the torsion bar and weight keep things tight in that direction. The axial play might allow movement under hard braking, but I doubt it since if those were sliding surfaces, the metal would wear over time without lubrication and who sees that? Anyway, if concerned about axial play, you might jam some metal shims or teflon sheet between the metal parts. Even new, there is some axial play.
 
Thanks for the warning. Luckily I will not be driving it until after a front bar is installed as well. The thing currently will not stay aligned, and I haven't had it above 20 mph in awhile.
 
More to think about, thank you. I will get pictures up when I tear the front apart again. One thing I know for sure, is my set of lower control arms are not as tight as any of the others I have seen. I would like to keep the poly bushings, if someone is using a set and can chime in on how they are working for them or tips on install, it would be appreciated. I can go to stock style bushings if need be, though. First I am getting rid of ALL of the other old cracked bushings up front. The strut bushings are just starting to get those age cracks, I will replace those as well.
 
Bill, I'm not sure why you couldn't hear the audio, but here's what I THINK it fixes. I've owned Mopars since the 1970s and some of them have a clunk in the front end when backing out of a driveway with the wheels turned. I believe this is the source of that clunk. Even if it's not, this is a simple job that certainly won't hurt anything to do.
 
Thanks for the video Jim. It's in my favorite file now.....
 
Jim, I tried again and could hear the audio today. A couple things make me suspect that slop in the LCA adjuster doesn't matter. I haven't seen where a factory manual gives any instructions on measuring slop or lists a specification. With weight on the wheels, the forces are very high on the adjusting bolt and rotating adjuster, given the small lever arm compared to total LCA length, maybe 10x the wheel's vertical load (~700 lb) so ~7000 lbf. The friction force is so high that it can't slide unless you hit a curb or lift the front wheels off the ground. Skidding the tires isn't enough.

I know that many people consider adding a stiffening plate to the bottom of the LCA essential. I don't see why one is needed. The strut rod takes out fwd-aft forces from the wheel so there is no bending load on the LCA in the horizontal plane. The strut bushings allow the rod to spring a bit, so it might be good for the LCA to bend a bit in sympathy rather than put all the turning on the LCA bushing. A stiffening plate probably doesn't hurt, other than adding a little weight and allowing gunk to build up and cause corrosion
 
Bill, I never said it was necessary, but I have hade arms that were tight and some that were loose. Like I also said, I've had many Mopars with that familiar clunk in the front end. I suspect that the slop is what causes this. As for the stiffening plates, on an all-out handling car they DO help. On a street car they are probably overkill.
 
It's been awhile since I updated this thread. Between family stuff and side projects I have left the Dart tucked away under a cover in the car port waiting patiently for me to start working on it.

I just seen the free shipping offer for orders over 99 bucks on summitracing and bought a Hellwig front swaybar, new ball joints, strut rod bushings, control arm bumpers/bushings to get the beast working the way it should! I am very excited to get it out and get dirty, best part is last weekend I hooked the battery up and it fired right up! (loving the electric fuel pump, I should put one in my Chrysler as well)

Other parts have been accumulated during my hiatus from working on the Dart, including a 42 tooth speedo(just what I need for my setup) gear I got for 10 bucks new in package from a co-worker before it ended up at a swap meet.

I have a wedding to attend (I am best man) this weekend, so I might not get too much done unless I get working hard on Sunday. What really fired me up was, the bride in the wedding asked if I could drive the Dart to escort them to the reception from the church. I was happy to hear her interest(says she loves the car), but reluctantly had to decline due to the unsafe condition of the front suspension. :/ My friend stepped up and offered to use his 79 Cordoba for the purpose so the bride/groom still get to ride in Mopar coolness to their reception. Alas, I am sick of not being able to enjoy my car, and I really need to line up with my co-worker's WRX to show him what's up! SO, the work begins! (again)
 
Now that I fixed a cracked transmission by building/installing a different 904 with some upgrades, I am back to the suspension on this car. I did not get adjustable strut rods-not yet anyways. But after close inspection, I did fine at least 2 ball joints having play, so now I am replacing all of the wear items.

Got poly bushings for the stock strut rods, the old bushings upon further inspection were thrashed. The UCA bushings have no play but I am replacing then anyhow. All new ball joints, idler arm, tie rod ends, shocks, and a Hellwig front sway bar.

Will have to get pictures up of my repairs. The LCAs will be de-played and boxed in like in the earlier video and will have the sway bar endlink mounts welded on when I am done with them.

Plans are to get this Dart to at least handle as good at my small block 76 Cordoba does, that car has front and rear sway bars from the factory and drives better than a late big smog era car should in my opinion. A job/town change have slowed my progress on this car, but the time to get back to work on it is now, finally. Will keep you updated. :)
 
So I have been working on the car on weekends when I have time.

Replaced the bushings and ball joints on the control arms. Fit and welded sway bar tabs. Did the lower control arm repair as in the video. They are good and tight now, still move but absolutely no slop. Instead of boxing in the entire bottoms of the lca's, I just welded a bolt on the unsupported bottom of the arm on the torsion bar side.
View attachment SAM_0194.jpg
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Note the difference between the repaired and not yet repaired control arm.
View attachment SAM_0204.jpg
Both are now done, cleaned up the parts and painted them.
 
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