Upper control arm preload?

[joshuawesl]

Replacing upper control arms in my 2003 Durango. I understand that the bushings should be tightened with some weight on the suspension.

As I have the wheel off - access is substantially easier. I have jackstands supporting the front side I'm working on, so could I theoretically just place a floor jack under the suspension assembly, pump away at it until the vehicle just comes off the jack stand, and tighten the bushings?

Or would it be best to just get the wheel back on, get the vehicle sitting level, and then tighten?

 

[Chris142]

Tire on the ground

 

[ARCOgraphite]

If you lube 'em it may not matter as much.

I would Lube 'em and do what you were going to do.

Just completely re-built a '67 buick skylark front end

- all bushings, in the upper and lower A- Arms.

New Ball Joints

and new sway bar bushings and end links.

NO Issues - the car drives NEW.

I just used the screw jack to lift up the LCA to "near level"

 

[slo town]

If they are rubber bushings that need to be pressed in, do NOT lube them. Let me clarify. When pressing in rubber bushings I often times use a window cleaner (Windex) or a very weak solution of dish washing soap and water (liquid Dawn) when pressing them it. That said, NEVER use grease intended for poly bushings. The bushings will turn in their bores and wear prematurely.

And, yes, like Chris said, tighten with the car on the ground and at its normal ride height.

Scott

 

[Trav]

On some vehicles it is impossible to gain clearance needed to tighten them with the wheel mounted on the ground, in that case load the suspension from the lower arms and tighten. It doesn't matter how you load the suspension as long as its loaded.
WD40 for rubber bushings works well and harmless to the rubber.

 

[kschachn]

I always liked how my old BMW manual showed the requirement (including passenger loading), you can get this any way you want as long as the measurement is met. This is for the rear but the front is similar:

 

[double vanos]

I take a measurement from wheel bearing hub to bottom of fender prior to starting. Lifting the arm til it just comes off the jack stands was pretty close to that measurement. Never had a problem.

 

[Kawiguy454]

Maybe I'm mistaken but aren't rubber bushings heat fused to the inner and outer sleeves? Neither sleeve ever rotates inside the rubber so no lube is needed. Lubing them can eat away at the rubber and cause the rubber to break loose from the metal.The rotation will then quickly wear out the rubber. Of course Poly bushings do rotate and need lube.

The Preload is supposed to "Capture" the inner sleeve in position with full load and rubber at rest. As the suspension moves the rubber provides elatomeric movement only and acts line a spring.

 

[Trav]

Some bushing do not use a metal ring just rubber, for these WD40 helps get them in easy and will not damage the rubber. The metal shell ones require no lube.
Both of these are for the LCA, the metal shell for RWD the all rubber for 4WD.

 

[ARCOgraphite]

Originally Posted by SLO_Town
If they are rubber bushings that need to be pressed in, do NOT lube them. Let me clarify. When pressing in rubber bushings I often times use a window cleaner (Windex) or a very weak solution of dish washing soap and water (liquid Dawn) when pressing them it. That said, NEVER use grease intended for poly bushings. The bushings will turn in their bores and wear prematurely.

And, yes, like Chris said, tighten with the car on the ground and at its normal ride height.

Scott


The "working" bores should be lubed for assembly - just a little.
The stationary part of UCA/LCA that press into the arms are captured in a shell and should not be lubed.

Got to be specific with working parts.

And poly or rubber anti-sway bar working bores should be lubed also. Unless you like squeaking and squawking.

You can use spit if you want for assembly. The fresh rubber has quite the bite to it.