Suspension changes or parts replacing

[booster]

This is just a quick FYI for those that are having suspension changes or parts replacements done, or are doing the work themselves.


I have seen statements lately several places of people watching coil springs being put into Chevies that said the installers had a hard time pushing the upper and lower control arms far enough apart to install the springs. This would indicate to me that the installer had not loosened the nuts at the inside pivots of the arms because of they did, the arms would swing free and require very little effort to move. On many vehicles the lower arm will hang straight down vertically when loosened.



Aside from the problem of making the job harder, this will also make the results of the work less durable, which may seem odd, but is true. The inside pivots are called "bushing" but really aren't traditional bushings that let a shaft rotate inside them. The pivot bushings are bonded rubber on both the shaft side and the arm side, so all the rotating is done by flexing the rubber, no sliding at all unless you have aftermarket urethane or other high performance bushings. That is whey they are so hard to pry apart far enough if you don't loosen the shaft nuts on them as the rubber is pretty hard to flex that far.



The actual problem caused is at the end of the job. The rubber in the bushings is intended to be in the "neutral" position when the vehicle is sitting on the wheels at normal weight, and the only way for that to happen is to loosen the nuts on the pivot shafts with van on the ground, and then retighten them. This is not a hard thing to do on a front end rack, but can really be a PITA if you are in the driveway unless you drive it up on blocks. If the bushings are not in the neutral position they will be more heavily stressed and be more prone to cracking and early failures.


This also applies to rear leaf spring eyes and most shackles, as well as vehicles with similar bushings in rear trailing arms and track arms.


Very few shops do this, that I have seen anyway, and many DIYers haven't heard about it, but nearly every factory service manual I have seen specifies to do it.