Bench testing shocks
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d.j. moordigian
Well-known member
I believe it's in the Service Bulletins Book...
Kevin in NJ
Well-known member
First look at what is inside, should be some kind of oily stuff- not rusty nasty looking.
Clamp in vice. Use large wrench to try and move.
If the shaft is at an angle or has play then it is worn and can not work right.
Should be slow moving in one direction and a little less slow in the other direction.
When you close off the adjusting valve it should get slower. If closing the valve does not make it real slow then it is worn which is not good or something is not right inside.
What you have to be able to feel is when the slow moving is to fluid moving and not the shaft binding.
If you buy enough cheap shocks that look like candidates you always feel good when you spend $5 on a shock that has possibilities. Next you have to get it apart- that can be a different story.
Details are in the Service Bulletins as far as weights on an arm and time of weights falling.
Clamp in vice. Use large wrench to try and move.
If the shaft is at an angle or has play then it is worn and can not work right.
Should be slow moving in one direction and a little less slow in the other direction.
When you close off the adjusting valve it should get slower. If closing the valve does not make it real slow then it is worn which is not good or something is not right inside.
What you have to be able to feel is when the slow moving is to fluid moving and not the shaft binding.
If you buy enough cheap shocks that look like candidates you always feel good when you spend $5 on a shock that has possibilities. Next you have to get it apart- that can be a different story.
Details are in the Service Bulletins as far as weights on an arm and time of weights falling.
Kurt in NJ
Well-known member
Have you looked in the service bulletins at the test fixtures there??
I have a shock arm that was cut off when I got it on a shock,filed a notch in the bolt so it could just slide on, welded a piece of pipe a little over 2' long(a precut length from scrap pile)---a good shock with the needle valve closed will move with resistance in the upstroke, and almost not move on the down stroke , not ever having seen the real test weight I guessed it was about 15 lbs, and adjusted my shocks to the spec in the bulletin ---makes the car a dream to drive when the shocks work properly
I used to carry a mediun sized adjustable wrench(8"), using much effort a shock can be felt to see if there is "normal" movement---that the resistance changes--easier to move in one direction, and if it has internal "free play"---which could just mean that there is air in the working chamber, then if it is held in the normal operating position that working It back and forth bleeds the air out of the working chamber and "replenishes" the oil in the working chamber properly---you can feel the bubbles squishing through the orfices and moving---when that feeling goes away it is bled and lost resistance motion should be gone if the shock is good -----without having sdomething solid to anchor the shock and give it some force it is just a guess if it works properly ---I doubt that most "rebuilt" or repro shocks can pass the testing in the service bulletins, about 2 in 20 shock cores are good enough to be able to be rebuilt economicaly to original specs and fluid viscosity useage.
If the shaft rattles or is off center it is not an econimacally rebuidable shock, cores that are "stuck" could be very nice inside but just have dried up fluid.
For a car that you want to drive and have it drive properly while keeping the original looking shocks I would consider Bill Stipe shocks, spend the $$ and enjoy the ride, I went the route of taking apart 100 shocks to come up with very good ones to make properly working shocks, and spares
I have a shock arm that was cut off when I got it on a shock,filed a notch in the bolt so it could just slide on, welded a piece of pipe a little over 2' long(a precut length from scrap pile)---a good shock with the needle valve closed will move with resistance in the upstroke, and almost not move on the down stroke , not ever having seen the real test weight I guessed it was about 15 lbs, and adjusted my shocks to the spec in the bulletin ---makes the car a dream to drive when the shocks work properly
I used to carry a mediun sized adjustable wrench(8"), using much effort a shock can be felt to see if there is "normal" movement---that the resistance changes--easier to move in one direction, and if it has internal "free play"---which could just mean that there is air in the working chamber, then if it is held in the normal operating position that working It back and forth bleeds the air out of the working chamber and "replenishes" the oil in the working chamber properly---you can feel the bubbles squishing through the orfices and moving---when that feeling goes away it is bled and lost resistance motion should be gone if the shock is good -----without having sdomething solid to anchor the shock and give it some force it is just a guess if it works properly ---I doubt that most "rebuilt" or repro shocks can pass the testing in the service bulletins, about 2 in 20 shock cores are good enough to be able to be rebuilt economicaly to original specs and fluid viscosity useage.
If the shaft rattles or is off center it is not an econimacally rebuidable shock, cores that are "stuck" could be very nice inside but just have dried up fluid.
For a car that you want to drive and have it drive properly while keeping the original looking shocks I would consider Bill Stipe shocks, spend the $$ and enjoy the ride, I went the route of taking apart 100 shocks to come up with very good ones to make properly working shocks, and spares
