Testing uninstalled shocks

packmule1911

Active Member
Joined
Jan 16, 2015
Location
Durham NC
I grabbed what look to be Procomp shocks for cheap from an XJ with a blown motor.

How do you determine if they’ll still good before going through the trouble of installing them? They do not expand quickly when you push the piston in. Should they?

Thanks.
 
packmule1911 said:
I grabbed what look to be Procomp shocks for cheap from an XJ with a blown motor.

How do you determine if they’ll still good before going through the trouble of installing them? They do not expand quickly when you push the piston in. Should they?

Thanks.
Click to expand...

If they are procomp, most of their es1000-6000 lines don’t have a nitrogen charge. So they won’t extend if you compress them.
 
They look like ProComp’s to my inexperienced eye.

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Not all shocks extend on their own, many just dampen. If they have plenty of resistance and don’t leak they’re most likely good. They should be very hard to compress and very hard to pull out. Only thing is sometime shocks can seem good but once they move a bunch they get hot and lose their resistance.
 
Thanks. The lack of rebounding was what I was concerned about, and it looks these are made that way. No leaks, and resistance is pretty equivalent in either direction.
 
As others said, gas charged shocks will extend quickly when compressed. Hydraulic charged ones won't. Typically, most white bodied shocks are cheaply made and hydraulic unless they're a xx9000 Series by whomever puts their sticker on the shock body.
 
Gearing up to 3 link my YJ and I will be going with Doetsch Tech 8000 Prerunner shocks. Nothing fancy, basic white body shocks with some simple bump stops built in. I’ve had good success with them on my XJ and know 3 other rigs running them with good luck. Not a bad shock for the money!
 
packmule1911 said:
I grabbed what look to be Procomp shocks for cheap from an XJ with a blown motor.
Click to expand...

packmule1911 said:
I know that vehicle they came off of, and they weren’t on it for all that long.
Click to expand...

So if you knew there vehicle they came off, and the approximate age of the shocks, why do you question if they're good? If it was a road car, I'd say if it has 50k-75k, they are due for replacement. If they aren't 2-3+years old, if they were the right price (10-15/ea), then I'd say install them and it'll be fine. If you don't know that, I'd recommend finding new ones.
 
I had a bunch of used shocks at one time that I wanted to evaluate before using. I built a test device out of 2x4’s with a bathroom scale. I could compress the shock noting lbs of pressure at a certain rate of motion and extend it back at feeling a certain resistance. Now I know this wasn’t very scientific. But I could feel a difference between shocks. The only shocks that failed were the ones that had leak oil. The other failures were the rubber bushings.
 
So many people fussing about the quality, lol. Often cheap shocks do just as good as high dollar around here.

If the shock auto extends that will give you a stiffer ride which is good for paved roads.

To tell if it's good:

1. Look for leaks? No leaks 99% chance it's good.
2. Extend it and compress it. If you feel resistance both ways, 99% chance it's good. Just make sure the shock is in a vertical position for an hour before you test so the oil will go to the bottom.
 
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