Lower Control Arm Pivot Shaft Issues

[Wietse]

I just did my front suspension as well and run against the same issue as OP did.
They were installed anyway as i had nothing else for now to replace them with.
It did need a hydraulic press to get the pivot shaft in, after walking about and getting ready to press it in the LCA the pivot shaft just fell out...
Imagined after pressing it in the LCA it would end up tight maybe but it did not.
Other side was exactly the same story.

Did notice the old bushings were also very easy to remove, the shaft did not appear to be worn, this also should have left a small lip on it if it was worn.
Tightened them using a vice grip, after setting the ride height and the weight on the suspension i did the last tightening without the need of a vice grip as it would no longer turn when tightening the nut.

I used the same bushings as mentioned before, MOOG MK791.

 

[Roadrunner40]

Well I ordered new shafts and bushings from pst yesterday hopefully it fixes it
Will report

 

[Wietse]

I think i wil end up doing the same, just wait and see how it will help you out.
I will need to change my torsion bars as well so i can do it all in 1 go.

 

[PST]

You should be able to torque our OE style pivot shafts to the factory spec which I believe with 145lbs with no issue. Now this should be done by hand using a torque wrench. These shafts are made in the USA (Pennsylvania) for us and are made to meet a exceed oem standards.

If you ever have any questions about our products please feel free to pm or call me.

Thanks
James From
PST Marketing
1-800-247-2288

 

[dadsbee]

Well you can't.. and I tried and just North of 100 ft-lbs they started to let go. Them or your supplied nut, I wasn't pulling it apart to find out which.

 

[PST]

We stand behind all the parts that we sell and if there was a problem it would/will be corrected. If you have a problem I would suggest calling our customer service manager at extension 307 and tell him I referred you. I have personally installed a set on both a Road Runner and Duster and was able to torque them to the proper spec with no issue.

Thanks
James From
PST Marketing

 

[dadsbee]

Sorry James, I wasn't redoing the complete disassembly of a restored LCA and repressing bushings and shafts. I've been assembling critical components for over 25 years in aircraft, I know when threads let go by feel and I immediately stopped and left it as is.

 

[PST]

I am not questioning your ability by any means. All I am saying is that we stand behind our products and if there is a problem please call into out customer service. We qc our products and preform periodic testing to ensure that it meets our standards. If you feel that there is an issue with our product. Then I would suggest calling our customers service. Over the past 10 years of offering this product we have sold 636 sets with no returns. All I am saying is if you feel you have problem with a part it is better to reach out to our customer service. That is what they are here for.

Thanks
James From
PST Marketing

 

[Mopars & Missiles]

Sorry James, I wasn't redoing the complete disassembly of a restored LCA and repressing bushings and shafts. I've been assembling critical components for over 25 years in aircraft, I know when threads let go by feel and I immediately stopped and left it as is.

Your call, but I would be more concerned about those threads stripping on the pivot shaft than I would be about the bushing rotating a bit on the pivot shaft like the OP stated to start this thread. Like you, I've got over 30 years working in aerospace with missile systems, including lots of ordnance assembly/disassembly. Talk about "critical".

 

[Wietse]

Apply some copper coat or other anti-seize and reduce torque by 15-20%, ends up similar.

 

[dvw]

I just had the K frame off my racecar. Poly lowers slide on the pins for/aft with the torsion bars removed. Been this way 5 years. Car leaves wheels up and runs close to 150mph. Drives perfect. As stated the control arm is locked in with the strut rod.
Doug

 

[Wietse]

I had been thinking about this, but when the pivot shaft is locked in 100%, all torsion in the control arm is taken by the rubber bushing which, to me looks very excessive stresses for a rubber bushing.
Really wonder how this supposed to work properly. (might just be only to absorb some vibration etc.)
When installed loose, the pivot shaft will likely see more wear then normal as it is metal-to-metal contact and always in the same position but my old bushings came out loose as well and did not notice any "flat spotting" on the shaft and also inside the old bushing was nothing obvious seen.

I think it will survive long enough for us to forget about this

 

[threewood]

I had been thinking about this, but when the pivot shaft is locked in 100%, all torsion in the control arm is taken by the rubber bushing which, to me looks very excessive stresses for a rubber bushing.
Really wonder how this supposed to work properly. (might just be only to absorb some vibration etc.)
When installed loose, the pivot shaft will likely see more wear then normal as it is metal-to-metal contact and always in the same position but my old bushings came out loose as well and did not notice any "flat spotting" on the shaft and also inside the old bushing was nothing obvious seen.

I think it will survive long enough for us to forget about this

That is why the front suspension components are not tightened until it is on full running weight. If you tighten at one extreme and then sit the car on its' weight you have already stressed the rubber components. Tighten at ride height and you still have ample up/down movement within the tolerance of the bushing.

 

[zyzzyx]

So, you guys got me thinking and I went to PST's web site and saw the two types of
shafts. Solid and ones you can grease? I need to replace mine and was wondering
which ones are best for the street? Thanks!

 

[Wietse]

The greasable ones come with Poly bushings.
The other one you can include any bushing of your liking, rubber or Poly.

Quite some people recommended to stay with rubber bushings instead of Poly as the LCA does see quite some abuse and the rubber bushing absorbs this better.
For that reason i went with rubber bushings as well as mine as for street use as well.

 

[AR67GTX]

I used the PST shafts with rubber bushings without any problems. I did note a few subtle differences in shaft profile comparing them to the stock ones and even posted here about them. But they pressed in fine and tightened up fine. They appear to be a quality item overall.

 

[Wietse]

Root cause of them being loose is most likely caused by the amount of times a new bushing was pressed on, and/or over time came slightly loose which allows it to rotate inside the bushing during it's lifespan.
This very small interference fit will be gone by that time and only solution is replacement i guess.

 

[Roadrunner40]

Root cause of them being loose is most likely caused by the amount of times a new bushing was pressed on, and/or over time came slightly loose which allows it to rotate inside the bushing during it's lifespan.
This very small interference fit will be gone by that time and only solution is replacement i guess.

That’s what I’m banking on still waiting on bushings to come in the mail.

 

[Roadrunner40]

Ok so I got the shafts and bushings from PST!! Very nice parts the old pin diameter measured a heavy .807 the new pin is .005 difference measured a heavy .812 bushings went on very tight compared to old obviously. No spinning what so ever also was just curious of torque so I tightened them the press fit into k member very nice the old ones just push in also I was able to get the FSA spec of 130 Ft pounds with no problems and bushing rubber flexing like its supposed to when loaded of course I loosened them after and removed them from the k member and will tighten once they are loaded on ground at normal ride height so please don’t panic lol.
Thanks for all your the help on here awesome sight!!! Mopar Rules!!!

 

[Wietse]

Good to hear.
And good to know what all others can do to resolve the issue with loose LCA bushings...change your darn pivot shafts!! (incl. me)