Broken LCA pivot mount!!

Suspension, Steering and Chassis

  1. Scott's dart

    Scott's dart Well-Known Member

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    Just wondering if anyone has seen this and what's the best way to fix it!? @72bluNblu ?(I know this is kind of your niche!) Good thing my engine was running like crap last summer or I would've driven it more and it could've been catastrophic! Also how do you remove the pivots out of the LCA's?
    IMG-20200416-WA0004.jpeg IMG_20200416_150343.jpg IMG_20200416_164232.jpg
     
  2. 68gtxman

    68gtxman I used to reMember

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    Yes, this is pretty common. My GTX is making a noise that tells me I have the same problem on the passenger side. The fix is to reweld it and afterward, use a large washer with center hole larger than the tube welded over the tube/k-member area (after grinding it flat). I haven’t done this myself yet, but this is what I have read in the past. Hopefully, someone has photos for your reference. Good luck!
     
  3. rklein383

    rklein383 Well-Known Member

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    I wonder if my clunk is the same thing....
     
  4. TrailBeast

    TrailBeast AKA Mopars4us on Youtube

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    Yea, that happens.
    What I would do is clean the parts all up, grind some of the junk off and weld it back in.
    Unless I miss something, depending on how it is done reinforcing it might make your torsion bar retainer clips not fit back in the sockets.:D
    Other than that I wouldn't see a problem doing the big washer for reinforcement.
    It might slightly mess with your caster settings by 1/8 inch.
     
  5. cudascott

    cudascott Now I have a Hemi

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    To remove the pivot pin and bushing from the LCA press the pin out of the bushing first then press the center sleeve out of the bushing and remove the rubber then weld a big flat washer to the lip of the bushing the full circumference of it. Then press it out from the back side pressing against the welded washer. Most likely the inner sleeve will come out with the pin. To get the sleeve off the pin cut a straight line down the sleeve with a chisel not all the way through and it will slide off by hand.
     
    Last edited: Apr 16, 2020
  6. Scott's dart

    Scott's dart Well-Known Member

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    Thanks everyone! The hole is just a outbit whollered Already so I'm not sure what's the best way to ensure its straight!
     
  7. 72bluNblu

    72bluNblu FABO Gold Member FABO Gold Member

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    Yikes!!! As others have said, it's not uncommon for this to happen.

    This is going to be the biggest issue. With such a large hole it will be harder to line everything up than if you just had the welds break. Is the other side intact?

    If the other side is intact, you can take measurements from it. What I would do is press the pivot pins out of your LCA's. Then you can install the pivot pin back into the pivot tube, so you can use a level and a square on the back of the LCA pivot to get the pivot tube back into the right spot, comparing the angle on the LCA pivot to the other side to ensure it's lined up right. Once that is done you can tack weld it into place, and go about reinforcing the area around the tube. I reinforce the LCA pivot tubes on my cars for this exact reason. The first time I did it I used a Firm Feel K-frame reinforcing kit, which includes all the gussets you need for the whole K frame. Since then I just make my own out of 1/8" or 3/16" steel. The pivot tubes can be reinforced with a heavy duty washer from the hardware store, you want to get one that has a 1-1/8" inner diameter. The HD washers in that size are almost 3/16" thick and work great, you just section the washer so it sits flush with the top of the K frame and then run a bead around the inside diameter, just grabbing the outer edge of the pivot tube with the weld. Done correctly it doesn't interfere at all with the LCA pivot, so it won't change anything regarding the alignment or suspension movement. You do have to be careful, if you burn through the pivot tube you'll obviously have to clean the inside of the tube so nothing interferes with the pivot. A couple of pictures of the K's in my Duster and Dart

    img_2790_zpsj1t3mbyg-jpg.jpg

    img_1651_zpszs785a36-jpg.jpg

    As far as the LCA pivots go, as already mentioned they need to be pressed out. If you have a 12 ton press at home that will work, or you'll have to take them somewhere. Depending on how wiped out the bushings are sometimes they'll just pull out, I've actually had the arms fall off the pivot pins before when I pulled the torsion bars. You can also use a torch to melt the bushing, but that gets pretty messy.

    As for reinstallation, it depends a lot on whether or not you're going to stay with rubber bushings or go to polyurethane or Delrin. Rubber is actually the most difficult as it will require removing the old outer bushing shells. Poly and Delrin are more expensive because to really do that right you need adjustable strut rods and greaseable pivot pins. There are pros and cons to all of them, it just depends on how you're going to use the car and what your own abilities are to do alignments and things like that.

    I took a bunch of pictures when I installed the BergmanAutoCraft Delrin LCA bushings in my QA1 lower control arms. A lot of that process is the same, as the Delrin bushings also require removing the old outer bushing shell. I use a large tap for removing the shells, it makes pulling the shells super easy. Here's the post in my build thread
    My "new" '74 Duster- or why I need a project like a hole in the head

    And a couple pictures of the removal process...

    The LCA, pivot pin and bushing assembly completely disassembled, this was done by pressing the pin out with a 20 ton press. Everything separated cleanly as these were all new parts. Be sure if you do the pressing that the LCA is properly supported so you don't bend anything.
    img_3925-jpg.jpg

    Threading the tap in
    img_4321-jpg.jpg
    Pressing the shell and tap back out. You can see the plates under the LCA, the other thing underneath it is a really large nut from a Dana 44 assembly that just happens to be larger than the outer diameter of the bushing shell but smaller than the end of the LCA, so it supports it perfectly.
    img_4322-jpg.jpg

    The shell after removal. After that the reassembly is a bit different because of the Delrin bushings.
    img_4324-jpg.jpg
     
  8. Scott's dart

    Scott's dart Well-Known Member

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    Wow thanks so much for the detailed reply! The other side is still perfectly intact! I guess I'll have to do some measuring and reinforcing then! I've got access to a press so that's no problem! So what made you go with the delrin ones over poly ones if you don't mind me asking?
     
  9. 72bluNblu

    72bluNblu FABO Gold Member FABO Gold Member

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    No problem, happy to help if I can.

    If the other side is perfectly intact than that's great, you can use the other side to pull angles and measurements off of to get the damaged one back into the spot it needs to be. I'd mount the K frame up on something and then either level it or the other LCA pivot. That way you can pull measurements and get the repair work done.

    I actually replaced my poly bushings with the Delrin ones on my Duster. The Delrin is self lubricating, so unlike the poly bushings it shouldn't need to be greased. The Delrin bushings are also more firm than poly, so, less deflection of the LCA than with the poly bushings. Although the poly is already much stiffer than the original rubber bushings. The Delrin bushings also replace the outer shell, which can be an issue with the poly bushings. I've run the Energy Suspension poly LCA bushings in the past, and they re-use the original outer bushing shell. Which makes installing the poly bushings pretty easy, IF they fit correctly. The outer shells have some tolerance to them, like anything but especially anything from the era of these cars, so you do have to make sure that the poly bushing fits tightly into the shell. If they don't the poly bushing won't work properly.

    Mostly, I just wanted the next greatest thing. I was in there doing the work, the Delrin was out there and track tested by Peter Bergman, and I wanted to give it a rip. I've never had an issue with the poly LCA bushings, and in fact I have poly bushing installed on my '71 GT for when that one hits the road. The Duster is set up pretty aggressively for handling so it makes sense to go Delrin on it. With the poly bushings I make sure they fight tightly into the old outer shells, I use greasable LCA pins so they can be lubricated, and I run adjustable strut rods so that the length of the strut rod can be tuned so the LCA is held in the proper location and there's no binding of the suspension. The Delrin bushings are just the "next step" from poly. I used my greasable pins from Firm Feel with them anyway, as they turned out to be the best fit for the Delrin bushings out of all 3 sets of stock pins I had and two different aftermarket pins. So although I shouldn't need to keep greasing the Delrin I have the capability to do that if I need to. Poly will squeak if it dries out, and because of the difference in how the bushing works compared to rubber it needs lubrication. Both the poly and Delrin bushings spin on the LCA pin, where with the rubber bushing all the travel is basically flex in the rubber bushings so the bushing doesn't move on the pin or in the shell. The poly is not self lubricating, so, it needs to be lubricated. The Delrin is supposedly self lubricating, so it shouldn't need further lubrication after install.

    @BergmanAutoCraft can give you more info on the Delrin bushings if you have any other questions. What LCA bushings you run really depends on the application. For how I set up my cars I would always use poly or Delrin, and the current quality of most of the rubber bushings out there right now (poor!!!) definitely adds to that. But I wouldn't use either of those without greaseable pins and adjustable strut rods because of the differences in how they work compared to rubber. The factory set up with the non-adjustable strut rods depends on having a ton of flex in the bushings to make up for the less than precise factory tolerances. Get rid of the flex by adding poly or delrin bushings and you need to dial in the strut rod length so nothing binds up.
     
  10. Scott's dart

    Scott's dart Well-Known Member

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    Okay awesome! I definitely would like my car to handle so I think I'll also go with delrin as well! Im from Canada and the exchange rate has gone from bad to worse in the last couple months so until that improves I can't justify buying parts but when I do I know what I'll get at least! Thanks again!
     
  11. Jim Lusk

    Jim Lusk Well-Known Member

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    I've got a jig that has a pair of pivot pins welded in the correct location so that when I had to fix my son's k-member last year there was no issue. The tube is also not straight. One end is tapered down so that the pin fits tightly. Somebody had "fixed" this before, but the pin was never able to get tight due to the extra metal they added. I usually cut a hole in the k-member so that I can reinforce it from the inside. The original welds were insignificant...Last pic is typical of the one end.
    20180916_144642.jpg 20180916_144626.jpg 20180916_132039.jpg 20180916_132050.jpg DW213185.JPG
     
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