LCA Bushings and Other Bushings
- Thread starter Old Tired Rebel
- Start date
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Ironracer
Gearhead
If it ain't a hassle, I'm down!
Ironracer
Gearhead
Upper control arm?
Yes
Ironracer
Gearhead
That's pretty damn ingenious...
TY, we’ll see how they work, For my 70-71 340 E/Stock Duster, weight transfer ya know.
GTMaracucho
Well-Known Member
Do you have more pictures??
GTMaracucho
Well-Known Member
Nice
What part?
Well you can slice and dice (link in earlier post is still good) like I did or go buy the adjustable strut rods.
Oldmanmopar has posted side by side photos of the fine thread and coarse thread strut rods. As Steve (autoxcuda) noted years ago, the dimensions are different.
On the launch foot braking the car as soon as you leave the pressure on the strut bushing releases and causes the lower control arm to bounce off the pin. If the OEM lower bushing is ripped from tightening the lower arm pin nut when not in the center of travel or if using poly slip in bushings.
Poly strut bushings disintegrate while putting pressure on them foot braking.
Put your car in a forward gear and step on the throttle this sinks the pin. In reverse it comes out 3/8-1/2 inch. My son video taped this after looking at this video below in slow motion. The front wheels would shake as soon as they would come up. The car is tied down in the front to keep the car from lifting as much as it did. The flatter the car leaves the quicker it is.
Coil overs and hymns are what we are using now. In a street car everything OEM. Strut rods with swivels were the worse thing we ever saw. They don't keep the arm stable at all. Try OEM and adjustable without the torsion bar using slip in poly bushings lubed up as instructed. Pry back on the arm and you will see the strut with the swivel comes off the pin. The OEM rod with poly bushings almost comes off. OEM bushings and rod it doesn't move.
We switching to coil overs now on the Demon, Struts are used on the Firebird .
Poly strut bushings disintegrate while putting pressure on them foot braking.
Put your car in a forward gear and step on the throttle this sinks the pin. In reverse it comes out 3/8-1/2 inch. My son video taped this after looking at this video below in slow motion. The front wheels would shake as soon as they would come up. The car is tied down in the front to keep the car from lifting as much as it did. The flatter the car leaves the quicker it is.
Coil overs and hymns are what we are using now. In a street car everything OEM. Strut rods with swivels were the worse thing we ever saw. They don't keep the arm stable at all. Try OEM and adjustable without the torsion bar using slip in poly bushings lubed up as instructed. Pry back on the arm and you will see the strut with the swivel comes off the pin. The OEM rod with poly bushings almost comes off. OEM bushings and rod it doesn't move.
We switching to coil overs now on the Demon, Struts are used on the Firebird .
How do those account for the slight misalignment of the axis centerlines?
If your LCA’s moved around that much after you installed your poly bushings, you installed them improperly. Plain and simple.
Improperly installed parts fail, everyone knows that.
If you install your poly bushings properly, and pair them with strut rods that are the correct length, the issues you describe are simply not physically possible.
And without a strut rod installed, you can pry the LCA off the back of the pin with the OE bushings too. The rubber will fail. The idea that a rubber donut wrapped around the pivot pin positively locates the LCA is just silly.
I’ve run poly bushings and adjustable strut rods on the street for over a decade and tens of thousands miles on multiple cars. Guys on this board with poly LCA bushings have run their cars at autoX events, on road courses, and the strip without any of the issues you describe. That much movement would result in massive changes of the caster angle and the vehicle would be completely unstable. It just doesn’t happen when the parts are installed correctly.
A few decades ago you improperly installed a set of bushings. They failed. Just admit you did it wrong and move on. Everybody makes mistakes.
yellow rose
Overnight Sensation
LOL...I don’t know how many times you’ve had to post this, but it’s at least several. And yet the myth continues on its merry way. You just can’t help the people who already know it all.
GTMaracucho
Well-Known Member
Low control bushing. I need the details of thois job please
It’s a lot more than several times.
It’s perfectly reasonable to prefer the OE style bushings, there are pros and cons to both styles. And you can definitely argue that the improvement from using poly or Delrin LCA bushings is fairly minor for a street car. I still recommend the OE bushings for some folks, like everything it’s application dependent.
But the poly LCA bushings have been available for a very long time now, decades even. They are produced and sold by ALL of the respectable aftermarket companies that make handling components for Mopars. Firm Feel, BergmanAutocraft, PST, Hotchkis, etc. And they’re used in pretty much all of the high performance handling builds, used on tracks, road courses, autoX’s, etc with great success. Dozens of members here use them without issues. Sure, they can fail if they’re not installed or maintained properly, but so can every other part on the car.
Bottom line is, if properly installed and maintained poly LCA bushings did what OMM says they do, no one could use them successfully. Not me or anyone else, not in any application. They would not still be available from all of those respectable companies decades later.
I’m honestly not entirely sure how a brand new set of poly bushings would fail as quickly and spectacularly as the ones OMM installed. Maybe that set was defective, it does happen. But properly functioning poly LCA bushings don’t move around like that, and they don’t fail like that. When I upgraded my Duster to QA1 LCA’s and Delrin LCA bushings the poly bushings that came off the car after over 10k miles were indistinguishable from brand new poly bushings after I cleaned them up. That’s how they should work.
How can anyone install poly LCA bushings wrong. You push them into the sleeves and then push the pin in. Oh yeah don't forget to lube them up with that special lube so they can go in and out real easy.
The strut rod bushings only go on one way. To destroy them you need Horse power. Apply the brakes real hard and do a burn out with big tires. 12 -15 inch wide Hoosiers . Racing on the street you don't always get to use water to heat the tires. Mine never lasted after some good foot brake races. They squashed apart just like if I would put them in a large vice in the shop.
We don't drive like old ladies here. We abuse everything.
The torsion bar does not hold the inside of the lower control arm front. The OEM sleeved rubber bushing does until its ripped and then there shot. Age or tightening the LCA nut without the car on the ground does ruin OEM bushings.
I just had a Challenger here that had poly bushings Had the customer watch as I backed it up and hit the brakes hard. The control arm backed off the pin at least 1/2 inch and stayed there until going forward. Try this for your self.
The strut rod bushings only go on one way. To destroy them you need Horse power. Apply the brakes real hard and do a burn out with big tires. 12 -15 inch wide Hoosiers . Racing on the street you don't always get to use water to heat the tires. Mine never lasted after some good foot brake races. They squashed apart just like if I would put them in a large vice in the shop.
We don't drive like old ladies here. We abuse everything.
The torsion bar does not hold the inside of the lower control arm front. The OEM sleeved rubber bushing does until its ripped and then there shot. Age or tightening the LCA nut without the car on the ground does ruin OEM bushings.
I just had a Challenger here that had poly bushings Had the customer watch as I backed it up and hit the brakes hard. The control arm backed off the pin at least 1/2 inch and stayed there until going forward. Try this for your self.
Dartswinger70
Well-Known Member
I make precision fit pins and delrin bushings. I purposely did not gun drill them for grease as I didn’t want to weaken the pin. A majority of the suspension load is on the lower arm, so this isn’t a place to experiment. I’ve even gone as far as Rockwell testing the originals and using the same material. This ensures safety in an impact causing the pin to bend not break. The material is more expensive to do this.
I’ve also made sure there is a degree of interference fit to compensate for temperature changes and break in wear. Delrin lasts longer than any Indian or Chinese rubber bushing and offers precision movement. I’ve installed many sets besides selling them and never experienced vibration in the steering wheel. Pushing the t bars all they way forward and drilling the socket for a set screw may satisfy some of people’s concerns. This is one mod that’s a nice upgrade from all the low quality rubber parts on the market. However, I respect the fact that upgraded handling is not everyone’s goal.
I’ve also made sure there is a degree of interference fit to compensate for temperature changes and break in wear. Delrin lasts longer than any Indian or Chinese rubber bushing and offers precision movement. I’ve installed many sets besides selling them and never experienced vibration in the steering wheel. Pushing the t bars all they way forward and drilling the socket for a set screw may satisfy some of people’s concerns. This is one mod that’s a nice upgrade from all the low quality rubber parts on the market. However, I respect the fact that upgraded handling is not everyone’s goal.
TheContractorDude
Active Member
I know this is an old post but I thought I would chime in on my recent experience installing the greaseable LCA poly kit available through PST. First off MOPAR's torsion bar suspension is a joy to work with as far as breaking down and reassembly. The most challenging step dealing with the LCA bushing is by far is the removal of the inner sleeve of the LCA bushing assembly. It is NOT as easy as everyone is saying it is. You will see all kinds of videos on this topic including welding a washer to the top in order to press it out from the back. This was a struggle for me and I ended up using a torch and chisel to drive it out. This approach worked well for me.
When installing the new poly bushing assembly you need to press in the sleeve provided FIRST! Do not attempt to press the poly bushing into the provided sleeve and then press in the LCA. You will end up with something like this. The top of the poly bushing will not retain its shape. I had to heat it up to get it somewhat where it was originally. Ended up purchasing another bushing. The shaft and inner sleeve where not damaged.
Once the poly bushing is installed you will notice the mushroomed top will NOT seat on top of the new sleeve.
You will also notice if you press the pin in with an extra pump on the press you will end up with some of the end of the poly bushing undermining the pin. So make sure you stop once the pin is fully seated. It doesn't seem to effect anything.
Now when installing the LCA in the K-Frame I had an issue with the pin turning in the bushing when using the nut provided. I had to purchase another nut and lock washer. You can't tighten the pivot shaft nut without the shaft itself turning. I did not expect this but it is a greaseable assembly. I will attempt to torque the nut after I lower the front end. The dimples on the nut catch the threads as they should however this makes the pivot shaft turn.
Here is the installed LCA. You can see the stop of the pivot shaft against the K-Frame.
Should there be a concern that the only thing really keeping the LCA in place is the strut rod and the clip behind the torsion bar? We shall see.
When installing the new poly bushing assembly you need to press in the sleeve provided FIRST! Do not attempt to press the poly bushing into the provided sleeve and then press in the LCA. You will end up with something like this. The top of the poly bushing will not retain its shape. I had to heat it up to get it somewhat where it was originally. Ended up purchasing another bushing. The shaft and inner sleeve where not damaged.
Once the poly bushing is installed you will notice the mushroomed top will NOT seat on top of the new sleeve.
You will also notice if you press the pin in with an extra pump on the press you will end up with some of the end of the poly bushing undermining the pin. So make sure you stop once the pin is fully seated. It doesn't seem to effect anything.
Now when installing the LCA in the K-Frame I had an issue with the pin turning in the bushing when using the nut provided. I had to purchase another nut and lock washer. You can't tighten the pivot shaft nut without the shaft itself turning. I did not expect this but it is a greaseable assembly. I will attempt to torque the nut after I lower the front end. The dimples on the nut catch the threads as they should however this makes the pivot shaft turn.
Here is the installed LCA. You can see the stop of the pivot shaft against the K-Frame.
Should there be a concern that the only thing really keeping the LCA in place is the strut rod and the clip behind the torsion bar? We shall see.
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