You should check pricing elsewhere for comparison if you decide to go ahead, even if you do trust this mechanic. ~~~~~ Copied the following from another group (I did not write this) some time ago, but made sense to me:
The "test rig" that Jason refers to is known as a shock absorber dynamometer.....and I own one.
Basically, it gives you a graph of the pressures produced as compared to the shaft velocities at which they are produced when the shock is moved at different speeds - ranging from a shaft velocity of one-inch-per-second to
20 i.p.s.
Basically, a shock that creates 200 pounds of resistance pressure while
moving at a shaft velocity of five i.p.s will =A0better control a car than a shock that only produces 100 pounds of resistance pressure at the same shaft velocity.
We use these graphs a bit differently in racing applications to "fine-tune" the suspension with shocks, but the above information is pretty much all you need to know for standard passenger automobiles....more shock pressure at a given shaft =A0velocity controls better than less pressure at the same velocity.
When internal valves and springs weaken and wear out (imagine how many cycles a shock valve control spring experiences in 50,000 miles of compressing to open and close the valving each time the shaft moves in or out) , they allow fluid to pass more easily at lower pressures - usually with no external leakage to suggest that any sort of problem exists.
The so-called "bounce test" only tells you if a shock will control a car while negotiating "Mickey D" parking lot speed bumps at less than five mph with a carload of rug rats and Happy Meals.
"Hand-testing" a shock off the car moves the shaft at a velocity of approximately one-half i.p.s.
A shock can "feel" good at slow "bounce-test" or "hand-test" speeds of one i=2Ep.s. or less because it is only passing fluid through its designed, low-speed, bleed orifices and/or bypassing the seals, but be a complete
failure at higher shaft velocities once it gets up onto the valving....sometimes, actually providing less resistance at five i.p.s.
then at "bounce-test" velocities once the valves open up.
On a smooth road, the shocks will likely be working in the 2-6 i.p.s. shaft velocity range....which simply cannot be duplicated by bouncing on the bumper of the car.
Best test for a shock (short of dyno-testing) is to drive it fairly aggressively - but carefully - over rough road. If the car remains under control, then the shocks are, likely, okay.
If one end or the other tends to "wash out", then new shocks (or struts)=20 are indicated.