Not happy with PST poly graphite lower control arm bushings

[R/T Boy 67]

In order for the LCA to move back,it would have to take the torsion bar with it. Probably not going to happen, with a fully loaded bar.

 

[1 Wild R/T]

In order for the LCA to move back,it would have to take the torsion bar with it. Probably not going to happen, with a fully loaded bar.

And yet it does... At different times I saw the inboard end of the LCA's move as much as 3/4".... No it can't go anywhere, no the outboard end doesn't move nearly as much as the inboard end but it does move.... I've never seen any movement with OE bushings unless the bushings are toast...

But wait, I must not know what I'm doing... PST rep says so....

 

[kiwigtx]

A lot of Prothane products I've used in the past squeaked like an old spring bed in a cat house.

Curious minds ask how you know this?

 

[Mike67]

Curious minds ask how you know this?

So I heard...them on my 70 GS....

 

[Kern Dog]

In order for the LCA to move back,it would have to take the torsion bar with it. Probably not going to happen, with a fully loaded bar.

Not necessarily. The torsion bar will keep the locating pin in place but the hex on the control arm is open and will allow the LCA to slide rearward.
I vote that the rubber does keep the control arm in place.

 

[1 Wild R/T]

Not necessarily. The torsion bar will keep the locating pin in place but the hex on the control arm is open and will allow the LCA to slide rearward.
I vote that the rubber does keep the control arm in place.

The torsion bar socket is captured by the control arm... But it still moves... The hex of the torsion bar is greased at both ends & while it would seem that it would lock in the socket that doesn't hold true in the real world...

 

[R/T Boy 67]

All the ones I have seen are blind on the hex end, and the T bar bottoms out on the shoulder.Well maybe not blind, but there is a shoulder in there.

 

[1 Wild R/T]

All the ones I have seen are blind on the hex end, and the T bar bottoms out on the shoulder.Well maybe not blind, but there is a shoulder in there.

But the distance between the rear crossmember retainer clip & the bottom of the socket in the LCA is greater that the length of the torsion bar....

 

[R/T Boy 67]

I agree. I tap them forward against the LCA shoulder, and tension them in that position. I have not seen any that have moved back, even the poly bushing ones, but as you have seen, it happens.

 

[StrokerSpanky]

Wow, nice introductory post.

Any chance of some background to how they were installed before racing off and blaming the product? They were installed with my press in my shop with new shells and new shafts. And I don't drive it like the Duke Boys. The first time I slammed on the brakes when a Honda minivan pulled out in front of me the control arm slid back on the polygraphite bushing. And I also have new PST adjustable lower strut rods with the hiem ball fittings which I DO like. Here's your pic.

Pictures will speak 1,000 words.

 

[68 HEMI GTS]

I put a pair of these in my barracuda during a complete front end rebuild. Everything new. I noticed rather quickly the lower control arm did slide back a bit. I ended up pulling it back down and putting rubber LCA bushings back in (as they do contribute to holding the fore and aft movement of the pivot point). The graphite’s need some more engineering, I wouldn’t use another set after my experience.

After reading through these posts it appears several people have all had similiar experiences. Starts to tell a story. Even the vendor stated this keeps coming up. As a vendor that should put up a red flag that the product needs a revamp.

 

[hunt2elk]

View attachment 1141532

Yikes, I wouldn't be happy either. Can't say that I've ever seen that happen before. Used poly in one car years ago and didn't like them. I only run rubber now.

 

[StrokerSpanky]

When you have a moment please private message me all of your information and I'll look into your issue. As for the lower control arm bushings if you're using the poly graphite style you would need to reuse your inner and outer shells. In Chrysler's design the lower control arm bushing is not designed to hold the lower control arm in place. The original rubber style bushings are vulcanized to the inner and outer shell and that in itself is not designed to bear the weight and hold the control arm in place from moving forward and aft. What essentially holds the control arm in place is the strut rod and strut rod bushing. If you have premature failure of the strut rod bushings this can lead to issues with the lower control arm bushings that you have described. Please feel free to contact me and we will work with you.

We are here to help but you need to reach out to us with your issues either direct through our website or by PM

Thanks
James From
PST

I have the PST adjustable lower strut rods with the hiem ball. I had them adjusted properly. Nice to get just a little more +caster with my radial tires. Bushings were installed properly with new shells and new shafts on my press, not with a hammer. Just so you know I'm not some shade tree mechanic I have an automotive engineering degree from OSU and worked for GM for 17 years and have almost all of my ASE certifications. Like that means anything. Those tests were easy. I went on to get my Airframe and Powerplant rating and work engines and flight controls on Boeing 737s and do a lot of work on Cessna's on the side including engine overhauls. The strut rod out at the ball joint end of the control arm can't do much to keep the lower control arm bushing from sliding back in a hard braking situation. That's when mine failed.

 

[StrokerSpanky]

I have came up with an engineering fix for this problem AND it will make removing the outer bushing she'll in the future much easier. No more welding a washer to the forward lip of the shell so it can be pressed out. If you would like I could draw it up and send it to you. With the limited number of these old molars on the road it may not be worth the design changes even though they are limited changes.

 

[oldmanmopar]

As similar discussion in poly lower control arm bushings seems to come up every couple of months and they are pages on this on both forums. But I am I will have to disagree in respect that vulcanizing of the rubber to inner and outer shell in some degree hold the control arm from moving forward and back.

The member 72BluNBlu post on the FABO pretty much sums it up. Below is one of his :

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.

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, 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. They would not still be available from all of those respectable companies decades later.

This guy bluNblu does not know his *** from a hole in the ground when it comes to this problem. And PST told me that the poly bushings were designed for flat roads not the north east or going in reverse. These bushings are scrap . My son Has a machine shop I do restorations . He now agreed its time to make a fixture and shut these scammers up and their lies. Site vender or not they are selling junk.

I know exactly what the poster is talking about . It happened to our car . The control arm was moving front to back on the bushing like a lubed up bull. I would imagine it was gushing air like a worn out cow.

 

[oldmanmopar]

When you have a moment please private message me all of your information and I'll look into your issue. As for the lower control arm bushings if you're using the poly graphite style you would need to reuse your inner and outer shells. In Chrysler's design the lower control arm bushing is not designed to hold the lower control arm in place. The original rubber style bushings are vulcanized to the inner and outer shell and that in itself is not designed to bear the weight and hold the control arm in place from moving forward and aft. What essentially holds the control arm in place is the strut rod and strut rod bushing. If you have premature failure of the strut rod bushings this can lead to issues with the lower control arm bushings that you have described. Please feel free to contact me and we will work with you.

We are here to help but you need to reach out to us with your issues either direct through our website or by PM

Thanks
James From
PST

You don't know what you are talking about! The strut rod holds the inner control arm? Give me a break. I guess it only allows up and down motion but not side to side. I hope you get sued for your lying BS.

I clearly watch as many other members at my shop did, The pin going in and out of the bushing. With and without adjustable struts. And easier with the pivot on an adjustable strut.
That is why the pivot was added was for easier motion is your own words as a sales pitch.

You need to be honest that you really don't have a clue on these suspensions and start telling members the truth, Give an instruction that the torsion bar must be held forward against the control arm to prevent this movement.

The T- bar can move back against the clip at the rear of the bar on rebound hitting the brakes in reverse when the T- bar relaxes from front end lift. If the control arm pushes it rearward being well greased as it should be to expand and contract and flex under compression and rebound

At that time the . Wheel attached to the spindle attached to the Lower control arm pries the bushing off of the pin using the strut as a pivot point. All the strut rod is there for is to stop rearward movement of the arm at the wheel side while still allowing the arm to travel up and down flexing at the K-member end due to the rubber bushing allowing it while under pressure driving forward

The early style bushings did not allow as much motion as the later larger 3 piece style. That is the reason they made the area that contained the bushing longer to allow thicker rubber. The thicker rubber allowed more movement , Replacing that rubber with a stiffer poly bushing just creates more friction and tears the bushing. The poly bushings do not and I say do not have a shear sleeve built in the bushings as pictured below as the new moog rubber does to prevent the destruction by the sharp edge of the K-member.

Just because you sell this junk does not give you the right to make up stories on this site to promote the sale. Improve your product or take it off the market.

You lie about the geometry of the suspension regarding the strut rod intention and you are not honest about the product you sell.

Hit a pot hole with the adjustable strut bolted fast to the K-member without cushion from the rubber and see what happens to the soft iron K-member at that area. You will need adjustment then. LMFAO

Then you mention a member 72bluNblu for instruction who has less of a clue what he is doing then you do. many of the kits and products you sell are good. Poly lowers and struts you should get rid of or improve and give better information. In my opinion they are a waste of hard earned cash.

Time for you to wake up and smell the coffee. There is places for these stiff bushings to work just fine, Not in the LCA's and the struts on these suspensions. They need to be better engineered not by you.

 

[Cranky]

This guy bluNblu does not know his *** from a hole in the ground when it comes to this problem. And PST told me that the poly bushings were designed for flat roads not the north east or going in reverse. These bushings are scrap . My son Has a machine shop I do restorations . He now agreed its time to make a fixture and shut these scammers up and their lies. Site vender or not they are selling junk.

I know exactly what the poster is talking about . It happened to our car . The control arm was moving front to back on the bushing like a lubed up bull. I would imagine it was gushing air like a worn out cow.

You don't know what you are talking about! The strut rod holds the inner control arm? Give me a break. I guess it only allows up and down motion but not side to side. I hope you get sued for your lying BS.

I clearly watch as many other members at my shop did, The pin going in and out of the bushing. With and without adjustable struts. And easier with the pivot on an adjustable strut.
That is why the pivot was added was for easier motion is your own words as a sales pitch.

You need to be honest that you really don't have a clue on these suspensions and start telling members the truth, Give an instruction that the torsion bar must be held forward against the control arm to prevent this movement.

The T- bar can move back against the clip at the rear of the bar on rebound hitting the brakes in reverse when the T- bar relaxes from front end lift. If the control arm pushes it rearward being well greased as it should be to expand and contract and flex under compression and rebound

At that time the . Wheel attached to the spindle attached to the Lower control arm pries the bushing off of the pin using the strut as a pivot point. All the strut rod is there for is to stop rearward movement of the arm at the wheel side while still allowing the arm to travel up and down flexing at the K-member end due to the rubber bushing allowing it while under pressure driving forward

The early style bushings did not allow as much motion as the later larger 3 piece style. That is the reason they made the area that contained the bushing longer to allow thicker rubber. The thicker rubber allowed more movement , Replacing that rubber with a stiffer poly bushing just creates more friction and tears the bushing. The poly bushings do not and I say do not have a shear sleeve built in the bushings as pictured below as the new moog rubber does to prevent the destruction by the sharp edge of the K-member.

Just because you sell this junk does not give you the right to make up stories on this site to promote the sale. Improve your product or take it off the market.

You lie about the geometry of the suspension regarding the strut rod intention and you are not honest about the product you sell.

Hit a pot hole with the adjustable strut bolted fast to the K-member without cushion from the rubber and see what happens to the soft iron K-member at that area. You will need adjustment then. LMFAO

Then you mention a member 72bluNblu for instruction who has less of a clue what he is doing then you do. many of the kits and products you sell are good. Poly lowers and struts you should get rid of or improve and give better information. In my opinion they are a waste of hard earned cash.

Time for you to wake up and smell the coffee. There is places for these stiff bushings to work just fine, Not in the LCA's and the struts on these suspensions. They need to be better engineered not by you.
View attachment 1416441

View attachment 1416412

View attachment 1416413

View attachment 1416414

What's that saying? You can catch more flies with honey than vinegar? Ya just don't have to be so rude, do ya? And that pin you speak of is called the lower control arm shaft.....

 

[68 Sport Satellite]

James from PST has always been a stand up guy and helpful to many of us on this site. Thanks James! I've bought from PST and have been satisfied with the products. However, I have never bought a poly LCA bushing as I also had read way back in 2010 when I first got my car that rubber LCA bushings were the way to go (but I'm also running most of the rest of the suspension stiffening pro-touring setup with bolt-on or weld-in goodies from Hotchkis, Firm Feel, US Car Tool, etc). Point is - all of us can always learn more. Let's keep the conversation a helpful collaborative one. Just because James is a PST rep does not mean he's just trying to make a sale. I know he reps the products, but he's not the product designer of course. I've always had the experience that he's here to help the hobby and its members and if he doesn't have all the answers he'll find out. Maybe on this topic there are technical disagreements and on some things you'll NEVER get agreed consensus even among experts, but let's keep things good natured with continuous learning for all.

Lying is an intentional thing. Sometimes people may be unaware or need to gain understanding. Other times there are different opinions.

 

[Cranky]

James from PST has always been a stand up guy and helpful to many of us on this site. Thanks James! I've bought from PST and have been satisfied with the products. However, I have never bought a poly LCA bushing as I also had read way back in 2010 when I first got my car that rubber LCA bushings were the way to go (but I'm also running most of the rest of the suspension stiffening pro-touring setup with bolt-on or weld-in goodies from Hotchkis, Firm Feel, US Car Tool, etc). Point is - all of us can always learn more. Let's keep the conversation a helpful collaborative one. Just because James is a PST rep does not mean he's just trying to make a sale. I know he reps the products, but he's not the product designer of course. I've always had the experience that he's here to help the hobby and its members and if he doesn't have all the answers he'll find out. Maybe on this topic there are technical disagreements and on some things you'll NEVER get agreed consensus even among experts, but let's keep things good natured with continuous learning for all.

Lying is an intentional thing. Sometimes people may be unaware or need to gain understanding. Other times there are different opinions.

I done the same thing.....went with a stock type control arm bushing and poly everywhere else. A couple of buddies went with 100% poly and had no problems but I didn't like the harshness. I think the LCA poly bushing adds a good deal more of the hardness into the ride....?

 

[PST]

This guy bluNblu does not know his *** from a hole in the ground when it comes to this problem. And PST told me that the poly bushings were designed for flat roads not the north east or going in reverse. These bushings are scrap . My son Has a machine shop I do restorations . He now agreed its time to make a fixture and shut these scammers up and their lies. Site vender or not they are selling junk.

I know exactly what the poster is talking about . It happened to our car . The control arm was moving front to back on the bushing like a lubed up bull. I would imagine it was gushing air like a worn out cow.

I have not personally nor have anyone at my company. Have ever said that our products are only to be used in flat areas. So unless you can provide me with that statement of myself stating that on this forum or via email. I would take what oldmanmopar has to say with a grain of salt. I personally have installed many of our poly components in Mopars here in the Northeast, specifically in Warren, Sussex and Morris county. We have hills. We have curves and we have flat areas to all of which our product has stood up for many thousands of miles

I would ask the members of the forums before passing judgment on myself or this member. Do yourself a favor and do a search on each of our posting habits. You will find that we both are very knowledgeable in Mopars, but you will also see that there tends to be a recurrence in many of his posting habits and what he has to say. I've never understood what his bone to pick with us is or our products but I would ask that you be the judge and not just take this one post from him as to what to live by when it comes to your suspension.

I'm not here to play tit for tat so I will not respond to any further of his posts.

But again, easily do a search and you will see that there tends to be commonalities in his posting both this site as well as the for A bodies only site. Polygraphite vs rubber

As for any of our products, we do stand behind them. If there is a problem with them, please PM me or you can call our customer service and we'll work to come to a resolution that will satisfy all involved.

Thanks
James From
PST