Proforged sleeved polygraphite LCA bushings!

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LovetheA's

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I wanted to know what the community thinks of these? I’m in the process of replacing my entire front suspension on my 67 Dart with a polygraphite kit from PST. While doing some research in order to do everything correctly I noticed something. A lot of people complaining that the pressed in fit with PST’s polygraphite LCA bushings aren’t the best. I’m hearing that the pivot shaft doesn’t fit nearly as tight within the polygraphite bushing as compared to the OEM rubber bushings which is inner and outer metal sleeved. Now PST claims to reuse the old outer metal sleeve and insert the polygraphite bushing into it then press the pivot shaft into that within the LCA. I read that people are complaining that there is slop or play between the pivot shaft and the polygraphite bushing. Not only is it difficult to tighten the washer and nut onto the pivot shaft because it spins but there is movement in the LCA which is bad. I did some research and thought what would solve this problem? A polygraphite bushing that is inner and outer sleeved like the rubber OEM bushing. Well viola what do you think? See pic.

0285A4B9-97D5-4A16-B701-25105AA04D6E.jpeg
 
Sounds like a great idea.

Personally, my big thing with parts nowadays is durability. The good, older rubber that had sulfur and other nasty stuff in it lasted a long time. I think the polygraphite should last as long or longer, hold alignment, etc. Sorry, ranting a bit.
 
LovetheA's, I agree with what you said above. Where can we get the ones in your photo ?
 
I bought a set of the proforged bushings just to see the design. They seem to be well designed, but, if you use the inner sleeve that’s installed there’s no way to lubricate them. So, if you install them as provided and they squeak, you’re pretty much screwed. The inner sleeves are a very tight fit too, so I didn’t attempt to install my set of greasable LCA pins since I wasn’t using the bushings anyway (I switched over to delrin). You’d have to press out the inner sleeves they come with and press in the greaseable pins. I’m sure they’ll just slide when you get going, but like I said my intention wasn’t to use them.

As far as the poly bushings that re-use the outer bushing sleeves in the LCA, the problem isn’t the bushings. It’s the crappy tolerances on the outer sleeves AND the LCA pins. I discovered that when I installed the delrin LCA bushings. The delrin is much harder, so the tolerance to the pin has to be much more exact, even than what is required of the poly bushings. After measuring a handful of LCA pins I have, I found pretty much all of them had significant diameter variance from one another. So, the problem with the poly bushings is that they depend on the OE sleeves and pins, which have crappy tolerances.

The other thing is, I don’t think the proforged bushings will stop the pins from spinning. Once the inner sleeve is pressed onto the pin there’s a good chance the sleeve will spin in the bushing, it’s just the material.

As for the original rubber, give me a break. It was shot within 50k miles. There’s TSB’s. The polyurethane, polygraphite, and delrin will all outlast he original rubber as long as they’re properly installed. And that’s the key, because the tolerances have to be more exact with the harder materials. You actually have to check that during installation, you cant just slap the poly bushings in there loose and expect them to work.
 
Ok so here’s the update on where I’m at with replacing the lower control arm bushings in my dart. Thank you everyone for chiming in and continue to advise me. I pressed out a set of original OEM rubber lca bushings so I would have an outer and inner steel sleeve to adapt to my polygraphite LCA bushings. Now there seems to be an issue. The polygraphite bushing isn’t tight enough within the outer steel sleeve that goes into the control arm. It can spin when I twist on it. Also the inner steel sleeve that goes inside the polygraphite bushing also isn’t very tight and I can push it in and out without a ton of effort. The only fit that appears to be real tight is pressing the pivot shaft into the inner steel sleeve. With all the motion or spinning within the LCA is it even worth it to install the polygraphite bushings? Here are some of my thoughts/changes?
1. Try to find a steel sleeve slightly thicker for a tighter fit within the polygraphite bushing. This may spread the bushing a little and tighten it up within the outer sleeve.
2. Wait to try to install the proforged steel sleeved polygraphite bushings I ordered? I’m just worried that they will have the same problem.
3. Just for the LCA go with OEM rubber bushings?
4. If I do go with a polygraphite bushing and the pivot shaft doesn’t have a grease fitting will I be ok if I grease the s**t out of the bushing between the polygraphite and the steel before I install? I was told that any metal to metal surfaces shouldn’t be greased. I don’t drive my cars more than 2,000 miles a year or in rain.
See pic below.

68CE210D-FC58-4773-8AF9-A87D173E774A.jpeg
 
When in doubt,go with #3. At one time PST and others stopped selling the poly lower bushings because of fitment issues.
 
The PST kit I just ordered came with the polygraphite lower control arm bushings and a set of rubber bushings, presumably to use the sleeve in case the original is not salvageable. I guess I will be able to see what fits best and decide which to use.
 
GMachineDartGT said:
OR, forget about the outer sleeve and purchase my delrins! No noise and lasts a super long time.
Click to expand...
I have a set of your Delrins but haven’t gotten around to installing them yet. So do you leave the outer shell in the LCA or press it out?
 
LovetheA's said:
Ok so here’s the update on where I’m at with replacing the lower control arm bushings in my dart. Thank you everyone for chiming in and continue to advise me. I pressed out a set of original OEM rubber lca bushings so I would have an outer and inner steel sleeve to adapt to my polygraphite LCA bushings. Now there seems to be an issue. The polygraphite bushing isn’t tight enough within the outer steel sleeve that goes into the control arm. It can spin when I twist on it. Also the inner steel sleeve that goes inside the polygraphite bushing also isn’t very tight and I can push it in and out without a ton of effort. The only fit that appears to be real tight is pressing the pivot shaft into the inner steel sleeve. With all the motion or spinning within the LCA is it even worth it to install the polygraphite bushings? Here are some of my thoughts/changes?
1. Try to find a steel sleeve slightly thicker for a tighter fit within the polygraphite bushing. This may spread the bushing a little and tighten it up within the outer sleeve.
2. Wait to try to install the proforged steel sleeved polygraphite bushings I ordered? I’m just worried that they will have the same problem.
3. Just for the LCA go with OEM rubber bushings?
4. If I do go with a polygraphite bushing and the pivot shaft doesn’t have a grease fitting will I be ok if I grease the s**t out of the bushing between the polygraphite and the steel before I install? I was told that any metal to metal surfaces shouldn’t be greased. I don’t drive my cars more than 2,000 miles a year or in rain.
See pic below.

View attachment 1715125080
Click to expand...

The "problems" you describe aren't problems. The poly bushings do not work the same way as the OE bushings, and that's why the poly bushings get a bad rap. People expect them to work the same way, and they don't. The poly bushings that were sold for years without the inner and outer sleeves also can spin within the shells. And, they NEED to. The old rubber bushings aren't all that different, they aren't bonded or anything to the inner and outer shells. It's just a friction fit between the rubber and the shell. It just so happens that the rubber is soft, so, it tears before the rubber spins in the shell. The friction between the shell and the rubber is stronger than the rubber itself in that method of loading. So, when the suspension moves up and down the OE bushings just flex back and forth. That's why you have to tighten them at ride height, because they'll tear if they're tightened somewhere other than the middle of the range of suspension travel.

The poly bushings are harder, and the material is much stronger. The bushing spins in/on the shells before it tears, and actually, before it deforms much at all. That's how it's SUPPOSED to work, there isn't enough flex in the material for the bushings to work like the originals. It's also why they need to be greased, because the poly will squeak when it spins if it's not. The pins can also slide in/out of the bushings, which is why I recommend using adjustable strut rods with poly bushings. The material has less give, so, the length of the strut rods has to be more accurate. If you run stock strut rods and rubber strut rod bushings, you may see some movement at the LCA pin/poly bushing. It was there with the rubber too, but the pin now moves in and out of the bushing instead of there just being a ton of flex in the rubber. With adjustable strut rods that fore/aft movement is better controlled (there still is some, because the arcs of travel are different for the strut rods and LCA)

The biggest issue with the poly bushings is using them with old outer shells. The factory tolerances weren't great, and replacement OE rubber bushing shells aren't any better. So, you have to check to make sure the poly bushings fit tightly into the shells. That's where a lot of the complaints about the poly bushings came from before, they wouldn't fit tightly into the old shells, so they'd wear out or function poorly if the fit wasn't checked, you couldn't just slap them in and go. The proforged poly bushings provide their own shells, so, that's a bonus, because the bushing should fit the shell just fine. That doesn't mean the bushing won't spin or slide in the shell, it just means the bushing won't flop around inside the shell. It should be a tight fit, but that doesn't mean the bushing won't spin. The inner sleeve seems like a waste to me. The reason being that the best way to use the poly bushings is with a greaseable LCA pin, not the stock LCA pin and proforged inner shell. No way to grease that later. The inner sleeve won't move on the LCA pin (or it shouldn't), but the pin/shell combination may spin in the bushing. It should be a tight slip fit, but it will still move (because something has to!). Which is why I use greaseable pins. If they start squeaking later, I can add poly grease.

If your plan is to use rubber bushings and stock parts elsewhere in the suspension, your best bet may to be use OE style rubber LCA bushings. If you're using adjustable strut rods, use the poly and get greaseable pins. Or, like Peter said, buy his Delrin bushings and don't worry about shells or grease. You still have to make sure the pins you use fit tightly (even more so than the poly) and I wouldn't use Delrin bushings with stock strut rods.
 
kg340 said:
$29.00 on amazon?? Rock auto sells them for like$17.50 a pair
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And then charges at least $10 for shipping and it takes a week. Or pay $29 total and have it tomorrow. Rock auto is great, but you have to remember to add shipping.
 
LovetheA's said:
I wanted to know what the community thinks of these? I’m in the process of replacing my entire front suspension on my 67 Dart with a polygraphite kit from PST. While doing some research in order to do everything correctly I noticed something. A lot of people complaining that the pressed in fit with PST’s polygraphite LCA bushings aren’t the best. I’m hearing that the pivot shaft doesn’t fit nearly as tight within the polygraphite bushing as compared to the OEM rubber bushings which is inner and outer metal sleeved. Now PST claims to reuse the old outer metal sleeve and insert the polygraphite bushing into it then press the pivot shaft into that within the LCA. I read that people are complaining that there is slop or play between the pivot shaft and the polygraphite bushing. Not only is it difficult to tighten the washer and nut onto the pivot shaft because it spins but there is movement in the LCA which is bad. I did some research and thought what would solve this problem? A polygraphite bushing that is inner and outer sleeved like the rubber OEM bushing. Well viola what do you think? See pic.

View attachment 1715124742
Click to expand...


I know the owner of proforged personally and the products that he provides are of very good quality and performance, But the main difference between the rubber (oe) and the aftermarket polyurathane LCA bushings whether it be from us, proforged, energy or prothane is the construction of the bushing. OE rubber bushings are vulcanized to the inner and outer shells. Making a permanent bond. Making the only give or rotation come from the rubber twisting on itself. Where as with the polyurethanes, are a insert so just like ours, proforged LCA bushing are pressed together and the inner sleeve moves independently of the poly bushing.

Thanks
James
 
PST said:
I know the owner of proforged personally and the products that he provides are of very good quality and performance, But the main difference between the rubber (oe) and the aftermarket polyurathane LCA bushings whether it be from us, proforged, energy or prothane is the construction of the bushing. OE rubber bushings are vulcanized to the inner and outer shells. Making a permanent bond. Making the only give or rotation come from the rubber twisting on itself. Where as with the polyurethanes, are a insert so just like ours, proforged LCA bushing are pressed together and the inner sleeve moves independently of the poly bushing.

Thanks
James
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James-

I'm sorry, but that's just not true about the OE rubber bushings. Take a set apart if you don't believe me. It's just a friction fit, there's no permanent bonding. At least not on any of the one's being sold today. It's true, the OE rubber bushings don't spin in/on the shells/sleeves and the motion is just the flex in the material. But it's just a friction fit that holds the bushing in place.

Brand new set of Moog LCA bushings, as they came in my QA1 LCA's. Please note the edge imperfections on the bushing already
IMG_3922.jpg


Pin pressed out
IMG_3923.jpg


Inner sleeve pressed out, bushing peeled out of the outer sleeve using a screwdriver, by hand. No bonding to hold it in, just the friction of the bushing in the shell. Notice how clean and smooth the shell is inside, the couple of scratches in the shell are from the tip of the screwdriver I used to peel the bushing out.
IMG_3925.jpg


The bushing itself. The rough edges were present before the deconstruction started. Notice the shape of the bushing! This is to create additional pressure on the sleeves to hold them in place, it's a friction fit. All of the material on the outside of the upper shoulder is pressed into the shell so it's even with that shoulder. It's hard to see in this picture but with the bushing out of the shells the inner part of the bushing is concave to allow for all that extra material to press in against the inner shell. The part of the bushing that was against the outer shell is nice and smooth, no tear outs from being bonded into the shell. And again, I removed the bushing by hand, so, definitely not "permanently" bonded.
IMG_4869.jpg
 
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I am sorry but I will have to respectfully disagree with you we sell both rubber and poly bushings The manufacturer that we work with to produce our OE bushing for the past 30 years does a process of vulcanizing the rubber in our bushings to the inner and outer sleeves. I have removed many pivot shafts from lower control arms over the years and when pressing them out the inner sleeve stay on the pivot shaft and piece of rubber stay vulcanized to the sleeve. I have also experienced this in many other applications like GM and Ford control arm shaft. Especially when the inner sleeve rusts itself to the control arm shaft.

The only way that oe does not spin is because it is vulcanized.

Thanks
James
 
PST said:
I am sorry but I will have to respectfully disagree with you we sell both rubber and poly bushings The manufacturer that we work with to produce our OE bushing for the past 30 years does a process of vulcanizing the rubber in our bushings to the inner and outer sleeves. I have removed many pivot shafts from lower control arms over the years and when pressing them out the inner sleeve stay on the pivot shaft and piece of rubber stay vulcanized to the sleeve. I have also experienced this in many other applications like GM and Ford control arm shaft. Especially when the inner sleeve rusts itself to the control arm shaft.

The only way that oe does not spin is because it is vulcanized.

Thanks
James
Click to expand...

Oh boy.

First, let me clean up my language here to eliminate confusion. I edited my previous post to reflect that as well. Vulcanization has nothing to do with bonding the rubber to the shells. It's a process used to toughen the rubber. Vulcanization actually results in the rubber being more non-stick, as well as mechanically tougher. It alters the polymer chains INSIDE the rubber. So, yes, the rubber in the LCA bushings is vulcanized. But it is not "vulcanized to the inner and outer sleeves", meaning some kind of bonding between the rubber and the sleeves. Not the same thing at all. What vulcanization actually is- Making Rubber Stronger: How to Vulcanize Rubber and Vulcanization - Wikipedia

As for any kind of bonding, I think it's really clear there's no bonding between the rubber and the shell in the sequence of pictures I posted above. It's a mechanical fit based on the compression of the rubber. That's why the bushing is shaped like a barrel with several different wall thicknesses- it's designed that way to increase the force created by the compression of the rubber on the shell and sleeve. That's why the bushing doesn't spin, because the compressive force and friction between the rubber and sleeves create a force that is higher than the force required to flex, and even tear, the rubber. Which makes sense, because rubber is really great in compression, and really lousy in shear once you've gotten past the deformation stage.

Sure, you can press the pin out and have the sleeve stay in place, but that just means there's less friction between the pin and the inner sleeve than between the inner sleeve and the bushing. And the bushing was designed that way, which is why it isn't just shaped like a cylinder. But you can press the sleeve right out of the rubber bushings. And as soon as you do that, the bushing will peel right out of the shell. Just like I showed in the pictures above. Pull one off the shelf and try it. The only bond between the rubber, the outer shell, and the inner sleeve is a mechanical one created by the compression of the rubber and the friction between the parts.
 
Anyone that wants to try this-

Get a stock style rubber LCA bushing. Use a socket that has a similar outer dimension to the inner sleeve. When the sleeve is pushed out, the socket will be just as stuck as the inner sleeve was (because it's a mechanical fit!). So now the socket is stuck, but you can then use an extension to press the socket out. Just make sure the extension is long enough to completely clear the bushing, because as soon as the socket pops out the other side you'll need to unhook the extension from the socket and slide it out the way it went in. The extension should be small enough in diameter that the bushing won't "grab" it, so it will slide out. Once the sleeve and socket are out, the rubber bushing material will peel right out of the outer shell.

It's a multi-step process because anything you use to press out the inner sleeve is basically the same outer diameter as the sleeve itself, so, it also has to be pressed out because the compressive fit of the bushing will hold it in place, just like it held the inner sleeve. If the sleeve was bonded in place, as soon as you broke the bond between the rubber and the sleeve you'd be done, the sleeve would slide out and whatever you used to press the sleeve would slide out too. That's not what happens. :D
 
I do know that I recently took apart two of the original OEM rubber LCA bushings in order to utilize the inner and outer steel sleeves to modify polygraphite or other bushings. Here is what I noticed. It doesn’t seem that the rubber is bonded to the inner or outer steel sleeve. Instead the rubber is compressed and stretched down to create the tight fit in the bushings. The steel sleeves were clean and no residue or bonding was present after I pressed out the bushings. It appeared that the rubber bushing is much fatter and shorter in height when taken out. The pressed in fit within the OEM bushings seem to stretch it in length and thin it out significantly when put between the two metal sleeves. I now have much better understanding of how these LCA bushings work and the functional differences between OEM rubber, proforged, polygraphite, or Delrin. The polygraphite, or steel sleeved polygraphites made by proforged are made to be able to spin/move on the inner steel sleeves as the LCA moves. Contrary to the OEM rubber which doesn’t spin and the flex and twist of the rubber allows for the proper functioning of the LCA. I again want to thank everyone on this site for chiming in and sharing their expertise. I wouldn’t be able to tackle all the jobs I’ve attempted without the support from the experts on here.
Carl
 
72bluNblu said:
Oh boy.

First, let me clean up my language here to eliminate confusion. I edited my previous post to reflect that as well. Vulcanization has nothing to do with bonding the rubber to the shells. It's a process used to toughen the rubber. Vulcanization actually results in the rubber being more non-stick, as well as mechanically tougher. It alters the polymer chains INSIDE the rubber. So, yes, the rubber in the LCA bushings is vulcanized. But it is not "vulcanized to the inner and outer sleeves", meaning some kind of bonding between the rubber and the sleeves. Not the same thing at all. What vulcanization actually is- Making Rubber Stronger: How to Vulcanize Rubber and Vulcanization - Wikipedia

As for any kind of bonding, I think it's really clear there's no bonding between the rubber and the shell in the sequence of pictures I posted above. It's a mechanical fit based on the compression of the rubber. That's why the bushing is shaped like a barrel with several different wall thicknesses- it's designed that way to increase the force created by the compression of the rubber on the shell and sleeve. That's why the bushing doesn't spin, because the compressive force and friction between the rubber and sleeves create a force that is higher than the force required to flex, and even tear, the rubber. Which makes sense, because rubber is really great in compression, and really lousy in shear once you've gotten past the deformation stage.

Sure, you can press the pin out and have the sleeve stay in place, but that just means there's less friction between the pin and the inner sleeve than between the inner sleeve and the bushing. And the bushing was designed that way, which is why it isn't just shaped like a cylinder. But you can press the sleeve right out of the rubber bushings. And as soon as you do that, the bushing will peel right out of the shell. Just like I showed in the pictures above. Pull one off the shelf and try it. The only bond between the rubber, the outer shell, and the inner sleeve is a mechanical one created by the compression of the rubber and the friction between the parts.
Click to expand...

I feel that this will go back and forth but here:

Vulcanized bonding of rubber to metal is a generic phrase that covers all aspects of the process by which an elastomer is chemically bonded to a pre-coated steel surface. Bonding rubber to metal is useful for products the require the strength of steel and the flexibility of rubber.
 
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Demonic said:
Sounds like a great idea.

Personally, my big thing with parts nowadays is durability. The good, older rubber that had sulfur and other nasty stuff in it lasted a long time. I think the polygraphite should last as long or longer, hold alignment, etc. Sorry, ranting a bit.
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Big Time! That's not something you want to do twice, or on a regular basis
I'm still hung up on what to do about my car. My Friend i got it from put in poly bushing.total junk not sure of age, but their causing things to move around. I'm not sure if I want to go with the polygraphite bushings and the new cans or the Delrin. I've heard some good about Proform or Proforged, rubber, but most of all of the rubber is garbage these days and even professional people at a rubber place here in the Tampa Bay Channelside district will tell you rubber has been garbage for over 10 years it started getting crappy over 20 years ago. I drove my car a few times and it's starting to heat up my brand new tires so I'm doing the interior now which direction did you end up going with the material you chose for your lower control arm bushing?
 
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