Lower, then tighten. Why?

[Mr Lee]

Just trying to understand something in the service manual under the Front Suspension section.  On the first page of the section it says that all suspension points that contain rubber should be tightened with the full weight of the vehicle on the ground.  Im just trying to understand why.  If everything suspension related is made to move, what's the difference if you tighten it at the top of the arc of travel (wheels hanging) or the bottom?

Also it says not to lubricate any rubber bushings.  I've always been of the opinion that if something moves, lube it.    There are exceptions of course but... As long as you use the right kind of grease.  From what I understand, petroleum based (like wheel bearing grease) is not good for rubber.  But what if you used non-petroleum based grease and are using poly-graphite bushings?  Sway bar kits come with grease for the end link bushings.  So why not grease the rest of them?





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[Chryco Psycho]

so that the bushings are not stressed in the normal position , if you tighten them raised & them lower the car the bushings are constantly under stress at normal height & will fail faster

[dodj]

The lower then tighten is so the rubber isn't twisted when you lower the car. Then when the suspension is compressed going over a bump or whatever, the rubber can be 'twisted' further, past it's elastic capabilities and it tears.
If you tighten after you lower, the rubber is in it's relaxed state so when it twists with the action of the suspension, it stays within its elastic range and does not tear.

[anlauto]

Rubber bushings typically have an outer metal sleeve that is anchored tight in the object, such as the LCA or the rear leaf spring. They also have a metal inner sleeve that is anchored to the attaching bolt or shaft in case of the LCA's. When the shaft (LCA's) or bolt (rear leaf spring) is also tighten, the only movement allowed is within the rubber.

If you tighten the above anchored points with the car hanging off of the ground...you're pre-loading the rubber bushings....When the car is lowered back to the ground, the rubber bushings are now twisting up a considerable amount putting unnecessary strain on the bushing.

[anlauto]

Dam...I type too slow...

[Mr Lee]

Ahh.  Got it thanks.  I didnt realize that the rubber was twisting in there and that was the thing that was allowing motion but I guess that makes sense. 



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[Cbridgewater]

Follow up question. What about for those who are rebuilding the suspension, motor, and tranny, and then going to install from underneath all at once. Won't it be difficult to tighten everything to spec once motor and tranny are installed?

[Shane Kelley]

Follow up question. What about for those who are rebuilding the suspension, motor, and tranny, and then going to install from underneath all at once. Won't it be difficult to tighten everything to spec once motor and tranny are installed?

No. All the bolts are accessible with the car assembled. 

[7212Mopar]

Put the wheels on blocks to raise the car up. Less work if you have a four post lift.

[anlauto]

Follow up question. What about for those who are rebuilding the suspension, motor, and tranny, and then going to install from underneath all at once. Won't it be difficult to tighten everything to spec once motor and tranny are installed?

The large nut on the front of the LCA pivot shaft should be left loose during all assembly. Not until the torsion bars are installed, and the ride height is set where you want it, should those nuts be tightened I usually leave it for my mechanic to tighten only after he's completed the front end alignment in case he makes adjustments to the ride height.

[Mr Lee]

So I would assume that this would have to be done with the upper control arm bushings as well, correct?

[anlauto]

So I would assume that this would have to be done with the upper control arm bushings as well, correct?

The UCA bushings will work on the same principal, however they will need to be loosened and tightened during the front end alignment.
For assembly purposes, I just put the camber bolts in the centered position and snug them up. If you don't snug them up, the UCA's have the tendency to move around when putting the car on the ground or moving it around the shop, in my case on to a trailer to take it to the alignment shop.

[dodj]

So I would assume that this would have to be done with the upper control arm bushings as well, correct?

Yup

[Mr Lee]

Any tips on how to tighten those cam bolts with the wheels on?  You need to have a wrench on either side of each bushing.


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[anlauto]

First off...the nuts should be on the engine compartment side. If the cam washer is properly seated in there seat, you should be able to get a ratchet on the nuts in the engine compartment enough to snug them up..it would take a bit of effort to turn the cam bolts.