I don't know much about shocks, but everytime I've picked up a new shock that someone is putting in, or on a store shelf, they are compressed, and if released they come out and are very hard to push back in. Well doing my front axles I have shocks dissconnected, there is no bounce back in these shocks, I can push them in to any point and that's were they will stay till I pull it out. So as I say, I don't know much about shocks, maybe lift kit shocks are different, this is an older Warn Black Diamond lift kit, only reason I haven't put in a new lift kit is my articulation is fantastic. But can someone let me know if these are dead shocks? Greg
On a CJ7 if you put gas charged shocks on, you will be needing a bikers kidney belt and you better be good friends with the dentist because your fillings will rattle loose.... Let alone ladies needing duct tape to help the sports bra along...
You test shocks with the bounce test. Bounce a corner hard and fast and see how many times it bounces when you let off. They fail at 3 bounces.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >
There are different types of shocks, some gas-charged, some not. What you really care about, is the resistance to being pulled out or pushed in (quickly). Some shocks are designed to compress easily, but resist being pulled back to normal operating length. Other than shocks that are obviously damaged, or that display no resistance at all, the only real way to tell, if you have "dead" shocks, is to put them on the vehicle and do the bounce test. After pressing down on the fender or bumper, and releasing, the vehicle should stop moving after one complete up and down cycle.
Earle
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As mentioned by previous posters the only way to test a shock absorber is while it is on the vehicle. You jounce the corner three or four times and then watch the result. You should get 1-1.5 jounce-rebound cycles, more than that and the shock is dying or dead.
Neither poster explained why though....
The reason that "new' shocks you are familiar with are under pressure is they are 'gas charged' (usually with nitrogen) which can be used to stabilize the ride and handling. They were introduced into the mass market in the mid 70's and progressively dominated the market as suspension systems refined to where they are today.
Before that the style of shock absorber was a metal tube composed of two chambers filled with oil with a valve in-between. There were differences in the valuing as Earle mentioned in some brands depending on the need/requirement.
The only function of a shock absorber in that 'older' style was to resist change (kinda sounds like Bill !) The resistance slowed the rebound when your wheel fell into a pothole and likewise slowed the jounce if you hit a bump. Their only action was to 'dampen' the action of the springs.
'Dampen" you say? That sounds familiar.....Yes.... older style shocks operate exactly the same way as your steering damper does now.
Mike is certainly correct in stating modern gas charged shocks can lead to a jarring ride in older vehicles that is not present in newer vehicles because as the use of the new shocks widened the suspension components changed also. The smaller and lighter the vehicle the worse the effect.
I am not sure who still makes the old style..... who out there has purchased them in recent years?
Sorry, forgot to mention it's an 81 CJ7, narrow track, 3 1/2 " Black Diamond lift, with Black Diamond shocks. I will wait till all is back together and try the bounce test. Thanks to all who replied.
There are basically two different shock absorber designs being used today. The first is hydraulic, which only resist movement in or out. Whatever position they are in, they will resist moving to any other position They do not expand on their own.
The second is gas charged, sometimes they are called nitros or nitrogen-charged. Gas charged shocks do expand on their own and can be difficult to compress by hand. One design, hydraulic vs. nitrogen, is not necessarily better than the other, either can be more appropriate for certain types of driving conditions.
Be aware that not all shocks that imply they are gas charged are indeed actually gas charged. For example, Rancho's R5000 shocks are hydraulic, not gas charged, so they will not expand out on their own... but Rancho's marketing information is misleading enough to make you think they are gas charged. :)
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