Noisy strut rod?

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clementine

clementine

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Shakin down the 67 fastback and I’m tracking down the rattles.

Seems like much of the offending noises are coming from my adjustable strut rods. PST pieces IIRC, so front is poly bushing through K frame, followed by heim joint and then solid to the LCA that has a 1/2” Allen bolt with star washer.

Home alignment so I relied upon the strut for a slight pull forward on the drivers side for improved caster, but very minimal. The drivers side seems to be more noisy.

Installer error? Should there be grease of some kind on the forward bushing that lives in the front of the K?

The noise seems to be more from where it (strut) meets the LCA.

Just looking for ideas before I disassemble and re assemble.

The LCA pins are Bergman units with Delrin I believe, but don’t quote me on that. Problem solvers in the upper.

Thanks FABO!!

IMG_1291.png
 
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clementine said:
Shakin down the 67 fastback and I’m tracking down the rattles.

Seems like much of the offending noises are coming from my adjustable strut rods. PST pieces IIRC, so front is poly bushing through K frame, followed by heim joint and then solid to the LCA that has a 1/2” Allen bolt with star washer.

Home alignment so I relied upon the strut for a slight pull forward on the drivers side for improved caster, but very minimal. The drivers side seems to be more noisy.

Installer error? Should there be grease of some kind on the forward bushing that lives in the front of the K?

The noise seems to be more from where it (strut) meets the LCA.

Just looking for ideas before I disassemble and re assemble.

The LCA pins are Bergman units with Delrin I believe, but don’t quote me on that. Problem solvers in the upper.

Thanks FABO!!

View attachment 1716297198
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I'm going from memory (not experience) that Poly Bushings Must Be Greased, and Often enough to Keep them that way.
Super-Cool Ride! btw
 
I'm guessing that you lubed the poly bushings where they pass through the K member?
You mention "noise" but not what type of noise. Squeak? Creak? Snap? Pop?
The sound you get by rubbing dry fingers on a rubber balloon is usually related to lubrication. A creak is often metal related where the parts are flexing. Snap can be where tension builds and then something suddenly shifts over, under, in, out, whatever.
You could disconnect one side at a time and see if the problem goes away or have a helper bounce the car while YOU are underneath looking for where the sound comes from.
 
When you say "noisy", what type of noise are you hearing? My adjustable strut bars have never made any type of noise. Maybe crystal ball time. LMAO.
 
WOW! Thanks for all the replies fellas.

I figured my post was lost in the ethos so I had a buddy do the fender humping while I checked out her struts (ok that is weird).

I loosened the front of the strut in the heim area and used some "fluid film" on the area.

The noise has gone away!! I could have swore that it was coming from the posterior strut rod where it goes into the LCA but my buddy was not so certain and he was correct.

but.....we will see how long it lasts.

image.jpg
 
Take the struts loose and put a good coating of grease on the faces of the bushings and reassemble. Your squeak should never come back.
 
Demonracer said:
Take the struts loose and put a good coating of grease on the faces of the bushings and reassemble. Your squeak should never come back.
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I hesitated to use grease as the dirt/dust attraction is high. I’ll see how long this stuff works for and adjust products if necessary.
 
The actual Poly-lube that I use is some white colored really thick goo that has a consistency much thicker than any axle grease.
 
Once reassembled, wipe away any excess grease and you should be good to go. I coat the facing of my bushing about every 12-18 months, just for peace of mind. My bushings show no excess wear due to keeping the area clean and servicing them like I do. Mine have been installed for over ten years.
 
Still wrapping my head around the K-member having poly bushings and then running a Heim joint. Seems redundant. That's two joints. A tighter thing being held in by a lest tighter thing.

Are you sure those two pucks clamping the bracket to the K-frame are not aluminum. Most kits are like that.
 
A few things-

PST adjustable strut rods do not contain any poly bushings. The front rod end (heim) is mounted using metal pillow blocks on either side of the K frame. The only thing that moves should be the heim joint.

Screenshot 2024-09-03 at 9.53.26 AM.png


The length of the strut rod should be set by cycling the suspension up and down with the suspension fully assembled, minus the shocks and torsion bar adjusters. Start with the LCA perpendicular to the frame rail, then shorten the strut rod length while checking for binding. The adjustable strut rods will likely end up being shorter than factory, especially with Delrin LCA bushings. You want to take all the space/slack out of the LCA to LCA bushing and K frame, but should not have to place it under any significant tension. You don't want to put an angle on the LCA, just keep everything pulled up together.

IMG_1787.jpeg


If the heim is making noise, there's a good chance it's under too much tension. I don't know for sure what rod ends PST is using right now, if they're just metal on metal or if they're a multipart piece with a urethane/delrin component.

There are rod end boots that can be installed to keep dust and grime out of the rod ends. That said, the QA1 strut rods on my Challenger did 70k miles with basically no wear and just the occasional shot of dry lube.
 
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I bought a parts hoard once and it had a full set of red poly front end bushings. Thought to myself ,Cool I can use these myself ! When I pulled them out of the package, they just crumbled apart. . Don't know how long they are supposed to last. . But personally I would never install these in my vehicle. .
 
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RAT ROD AL said:
I bought a parts hoard once and it had a full set of red poly front end bushings. Thought to my, Cool I can use these myself ! When I pulled them out of the package, they just crumbled apart. . Don't know how long they are supposed to last. . But personally I would never install these in my vehicle. .
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So, random bushings of an unknown manufacturer and unknown age, not to mention unknown history, are going to dictate your opinion on this. Rubber bushings deteriorate over time too, you know. Especially the new ones.

I've heard this old wives tale before, and despite using poly bushings in multiple different applications for decades and tens of thousands of miles I've never seen anything like it. It's almost like if you maintain them properly that doesn't happen.

Nevermind the fact that the topic at hand, adjustable strut rods, don't use poly bushings.
 
72bluNblu said:
So, random bushings of an unknown manufacturer and unknown age, not to mention unknown history, are going to dictate your opinion on this. Rubber bushings deteriorate over time too, you know. Especially the new ones.

I've heard this old wives tale before, and despite using poly bushings in multiple different applications for decades and tens of thousands of miles I've never seen anything like it. It's almost like if you maintain them properly that doesn't happen.

Nevermind the fact that the topic at hand, adjustable strut rods, don't use poly bushings.
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Yes !
 
@72bluNblu and @autoxcuda

They are the PST units.

Yes on the aluminum through the K.

Good to know about how to set them up. I may have put a bit of navy torque on those puppies to achieve certain caster goals…. Not a lot…. But what is that?

So slide torsion bars back?


Remove shocks
LCAs perpendicular
Check swing of front suspension.

Adjust strut to not bind

Torsion bars in and re align.

Check!!
 
clementine said:
@72bluNblu and @autoxcuda

They are the PST units.

Yes on the aluminum through the K.

Good to know about how to set them up. I may have put a bit of navy torque on those puppies to achieve certain caster goals…. Not a lot…. But what is that?

So slide torsion bars back?


Remove shocks
LCAs perpendicular
Check swing of front suspension.

Adjust strut to not bind

Torsion bars in and re align.

Check!!
Click to expand...

I leave the torsion bars in place, but remove the torsion bar adjusters. That way the LCA is supported/located the same as it will be on the road. You will get some drag from the LCA rotating on the torsion bar hex, but that should be constant. The bind usually comes in at the ends of the range of travel.
 
72bluNblu said:
I leave the torsion bars in place, but remove the torsion bar adjusters. That way the LCA is supported/located the same as it will be on the road. You will get some drag from the LCA rotating on the torsion bar hex, but that should be constant. The bind usually comes in at the ends of the range of travel.
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Copy that.

So with 1.03 bars and expected bind toward the end of range of motion, is it acceptable to have just MOST of the ROM ok and a little bind in the extremes? As the suspension will normally live in the middle?
 
clementine said:
Copy that.

So with 1.03 bars and expected bind toward the end of range of motion, is it acceptable to have just MOST of the ROM ok and a little bind in the extremes? As the suspension will normally live in the middle?
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In theory yes. Since all of the suspension components, including the LCA and strut rod, are moving in different arcs there will be binding at some point if the ROM is large enough. The goal should be to minimize binding as much as possible, especially in the majority of the normal range of travel.

That being said, I've always been able to get the full ROM pretty much free of binding since you're only talking about 5" to 5.5" of suspension travel. The ROM on my cars has been recentered around the lowered ride height, but like on my Duster even though the car is lowered close to 2" the ROM from bump stop to bump stop remains pretty much the same as the factory set up, so the suspension travel remains close to the same amount.
 
72bluNblu said:
In theory yes. Since all of the suspension components, including the LCA and strut rod, are moving in different arcs there will be binding at some point if the ROM is large enough. The goal should be to minimize binding as much as possible, especially in the majority of the normal range of travel.

That being said, I've always been able to get the full ROM pretty much free of binding since you're only talking about 5" to 5.5" of suspension travel. The ROM on my cars has been recentered around the lowered ride height, but like on my Duster even though the car is lowered close to 2" the ROM from bump stop to bump stop remains pretty much the same as the factory set up, so the suspension travel remains close to the same amount.
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If I recall correctly, you are running adjustable upper A arms as well,ya?

Also, how are you getting that low? I feel like the LCA bump stop would prevent that. I’m only 1/4” off it and while I’m happy to have it there, it is waaaay higher than yours.
Love that duster BTW.

The reason I ask about the adjustable uppers is that I put the navy torque on the strut to achieve caster (3.5*?+\-?, with the moog problem solvers)
And I know I have heard better numbers than that. I feel that if you are getting more (neg) caster than that with stock components then there must be witchcraft involved…. But I dunno
 
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clementine said:
If I recall correctly, you are running adjustable upper A arms as well,ya?

Also, how are you getting that low? I feel like the LCA bump stop would prevent that. I’m only 1/4” off it and while I’m happy to have it there, it is waaaay higher than yours.
Love that duster BTW.

The reason I ask about the adjustable uppers is that I put the navy torque on the strut to achieve caster (3.5*?+\-?, with the moog problem solvers)
And I know I have heard better numbers than that. I feel that if you are getting more (neg) caster than that with stock components then there must be witchcraft involved…. But I dunno
Click to expand...

Yes, I run SPC adjustable UCA's. My alignment is typically set up with -1° camber, +6.5° caster and about 1/16" of toe in.

For the ride height I have a bunch of stuff going on. I use QA1 tubular LCA's, which have a lower profile than stock LCA's so I gain almost an inch of travel from them, which I then lose to lower the car. The version I have is before they added bump stops, and I run a 3/8" tall bump stop on the frame horn. Since the factory bump stops are about 1 3/8" tall, I gain another inch right there.
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With 1.03" bars, you need much more than a 1/4" between the bump stop and the frame. Otherwise you will be constantly hitting the lower bump stops, which will affect ride quality and handling. That's going to be a bit of a dance, because if you just use poly bump stops that are 3/8" tall like I do you still might not have enough clearance to stay off of them all the time, and switching from a progressive rubber bump stop like the factory ones to a button poly stop also means using the bump stop a lot less, because it will be a lot more noticeable to hit the bump stop. If you have a 1/4" now though and went to 3/8" button stops you'd probably have enough clearance to maintain your current ride height.

As for the positive caster, that's not what the strut rods are for. Using the adjustable strut rods and poly/delrin LCA bushings does typically create some additional caster, but the goal of the strut rods has to be bind free operation of the LCA, not adding caster.
 
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