When to replace shocks?

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Shock Absorber Article

Interesting about the three valves, courtesy of ROCKAUTO newsletter. cut/paste as follows,

"What about oil leaks? Shock absorbers and struts contain hydraulic oil. Truly ancient hydraulic seals made from materials now considered inferior might have “dried out” or otherwise lost their ability to seal over time, but Monroe shocks were made with modern seals even in the 1990s. These new/old Monroe shocks do not have any oil leaks. The mounting bushings also look identical to any more recently manufactured new bushings.

What about gas leaks? A “gas” shock or strut usually has nitrogen gas in the oil reservoir. A gas shock is not the same thing as an air shock. The nitrogen gas is primarily intended to help keep the oil from foaming when the shock cycles rapidly on washboard dirt roads or at high vehicle speeds. If the hydraulic oil foams, then the shock’s damping capacity is reduced. If the shock’s oil reservoir is not leaking oil then it probably is not leaking nitrogen gas either. One of the reasons nitrogen is now used to pump up tires is that nitrogen molecules are larger and less prone to leaking than oxygen and other components of air. Ambient “air” is 78% nitrogen, so there is no strong chemistry working to force the nitrogen out of the shock’s oil reservoir.

Even shocks that have been driven way beyond the 50,000-mile mark over many years usually do not fail because of oil or gas leaks. Modern shocks use multistage oil valves. Each valve is a calibrated metal disk that flexes to let oil flow through in response to different road conditions. The first stage valve opens in response to little bumps, the second stage valve opens in response to medium sized bumps and the third stage valve opens in response to big bumps. These valves are usually what wear out first. The metal valves fatigue and go limp after millions of openings. The first stage valve is the first to die because the vehicle is constantly exposed to little bumps and the valve is constantly cycling.

Multistage valves are one reason the old push-down-on-the-fender test for shocks is now almost useless. If the car keeps bouncing after a big push down on the fender, then that means the third stage, big-bump, valve is now worn out, the second stage valve has been worn out for awhile and the first stage valve has been worn out for a really long time. A shock that fails the fender-push test should have been replaced long ago. That shock absorber or strut has not been protecting the vehicle’s suspension parts and assisting with safe vehicle handling and braking.

Time will tell, but I bet I will continue to be very happy with the new, fifteen-year-old shocks on my thirty-year-old 300. We will see what my son, the handling expert, says the next time I let him behind the Chrysler’s wheel!

Tom Taylor,
RockAuto.com"
 
Every 100k miles for me with a quality shock. I only replace OE with Bilstein, and those can go a bit longer sometimes.

The originals on my truck were shot at 100k miles. Two wouldn't even rebound if I compressed them by hand, and the other two could be pushed in with minimal effort. The internal valves were shot, yet the truck still passed the bounce test.
 
Bilstein on my Chevy, they are ok, I have the comforts now but have used the HDuty
Bilstein on all 3 of my Mercedes, for some reason these shocks are good on these cars
KYB previously on my civic, nope, not a good ride
Monroe sensa currently on my civic, don't get them. Worst decision

Tokico Blues, good
Koni, good

Showa shocks, the best I ever used, expensive.

Showa shocks were the original shocks(struts) that came with my 91 Honda Civic Si Hatchback.

Agree with hattaresguy. Bounce test is for basketballs
 
List of shocks/struts I've used/installed for clients so far:

-konis (monotube)
-bilsteins
-Tokicos
-KYBs
-Sachs
-Showas
-Gabriels
-Monroes
-Leacrees


I'm a big fan of Tokico blues, hard to get for specific applications sometimes...most of them still made in Jpn.

KYB's -quality inconsistent due to global manufacturing schemes: I had them failed on my in mere 10mnths time, returned for warranty replacement and 2nd pair lasted only 1.5yrs, ended up credit swap with Tokico blues.

Most NA built Hondas came factory OE with NA or some Asian built (not Jpn) KYBs, and they suffered from inconsistent, if not premature failures (even with the automobile still under factory warranty)...ask me how I know.

Jpn built Hondas typically came with either Jpn KYBs or Showas...mine came with Showa OEs.

Showa also make hood/hatchback charged lifter shocks...and they are the OE supplier for specific Jpn tuner shops catalogue parts including but not limited to HKS, Spoon Sports, etc.

over 1/2 of the NA built Toy mid-size vehicles came with Sach's OE struts or shocks...fairly long lasting if not reliable and good for around 120k....

I had bad/inconsistent results with Gabriel struts...failed prematurely during 10mth period. Shocks are ok.

Cheeper line of Monroes I don't recommend them at all. I now only deal exclusively with Monroe OESpectrum or Sensatrac...never fail me so far.

Leacree is the latest budget line of shocks/struts coming from china: cheep, fails quickly...good for cheep-minded.

KYB: There used to be an adjustable ones (with a dial knob) and body in white colour: those are good ones; all other ones are no longer good (silver body ones, GR-2, whatever).

My share of experiences with shocks and struts...YMMV.

Q.
 
I haven't used the bounce test in 20 years, but a new set every 100K is very noticeable. Koni is my favorite of the reasonably higher priced stuff, KYB is the most useless product I've ever tried.
 
The funniest story I have is my 70 year old Father-in-Law coming up to my car and trying to 'bounce test' the shocks.

The car didn't even move! I'm not sure a bounce tells you very much these days, especially with velocity sensitive valving...
 
Originally Posted By: SteveSRT8
The funniest story I have is my 70 year old Father-in-Law coming up to my car and trying to 'bounce test' the shocks.

The car didn't even move! I'm not sure a bounce tells you very much these days, especially with velocity sensitive valving...


I had someone try to do the bounce test on my 98 Mustang GT. I had Bilstein Race coilovers with Hyperco springs that were rated a little too stiff. The guy but his full body weight over the fender and the car didn't squat.
 
Originally Posted By: BISCUT
Originally Posted By: Chris142
Id say with that much milage you will notice a huge improvement with new ones. I rarely get 30k out of mine. They either break or leak .


What brands do you use? Leaking and/or breaking at 30k isn't anything I've experienced. I usually go the route of high quality for replacement. My application isn't anything tack related or truly HP related. Tokiko shocks on 97 Explorer went 130k and were still sound before the truck was totaled around 215k. I have Bilsteins on F150 (they are stiff!! but work great) I hope they last as long as the Tokiko's mentioned.

The BMW in my sig is 77k with original shocks and they are still A-ok. I'd imagine around 100k I'll be swapping them out. If I had to do that every 30k ouch!!
gabriels break by blowing the bushings out and monroes leak there oil out.keep in mind that our roads are so bad that driving on the shoulder in the dirt is smoother
 
Sonatas are known for having soft suspension, but at 100k miles I assumed my shocks/struts had to be worn.

I replaced them and there's very little difference in the ride/handling. I guess they weren't that worn.

I used Monroe OESpectrum, which appeared to be sourced from the company that made the OE shocks/struts, as they were identical down the the smallest detail. They were made in Korea, too, just like the OE struts.
 
Note that the only aftermarket brand that has impressed us and is reasonably priced for our extra heavy fleet vans is Gabriel Ultra.

They hold up well under pounding heavy duty usage and are very reasonable. Plus they are well priced, IMO...
 
Originally Posted By: SteveSRT8
The funniest story I have is my 70 year old Father-in-Law coming up to my car and trying to 'bounce test' the shocks.

The car didn't even move! I'm not sure a bounce tells you very much these days, especially with velocity sensitive valving...


Does your car have air suspension or SLS? I always crack up when someone tries that on a car like that, they don't even bounce! Actuary most will correct if you sit in the trunk.
 
I was told at 100k my struts were toast; I was not surprised, as online chatter said the OEM units were typically dead at 40k (VW Jetta, the A4 chassis). At 133k I had them replaced, I thought the problem I was having was from that--turns out a tire shop hadn't balanced the tires. Oops.

I put on Koni Red's, an adjustable strut, at near full stiffness. Which was probably too stiff, but after a couple of weeks I didn't notice anymore. For years there was series of bumps on I91 where the car would bounce all over the place; that was gone. Also, when coming to a stop the car would no longer roll backwards--if I braked hard enough, so as to get a bit of nose dive, with the old struts it would roll backwards when I let off the brake. That too seemed gone (never bothered me, just seemed like a fun "trick").

Fast forward another 130k, and local shop says the struts are dead. I have them replace the struts, but, for once I did not stick around the shop to "supervise". Shop was not impressed with my struts and installed at full soft! He said it still rode rough.

Thing is, I can't tell the difference whatsoever. Bounces around just like when the struts were dead. And the struts were dead, I could work them with no resistance whatsoever (returned under a lifetime warranty). Bounce test for me is the same, dead strut vs new.

I don't know how mechanics can tell, but my butt can't. If I keep the Jetta for much longer I will have to have the struts pulled and set stiffer.
 
Originally Posted By: hattaresguy
Originally Posted By: SteveSRT8
The funniest story I have is my 70 year old Father-in-Law coming up to my car and trying to 'bounce test' the shocks.

The car didn't even move! I'm not sure a bounce tells you very much these days, especially with velocity sensitive valving...


Does your car have air suspension or SLS? I always crack up when someone tries that on a car like that, they don't even bounce! Actuary most will correct if you sit in the trunk.


Mine has Nivomats by Sachs in the rear, they are the coolest self leveling shock design I have ever seen. Actually on a lot of cars these days. The fronts are Bilsteins.

http://www.zf.com/na/content/en/united_s...nivomat_us.html
 
My original nissan struts were shot with the car bouncing all over the road at ~250K. I replaced with ebay sen sens for $110 for all four courners and have been very happy.
 
According to Toyota you only replace them when they develop gross leaks. I have attached the TSB with the Toyota replacement criteria. I remember seeing a similar TSB from Honda as well. The bounce test has not been accurate for probably 15 years--every car I've had is too stiffly sprung for it to be accurate. My '87 Olds Cutlass was the last car soft enough for that to work. Based on that experience, and the Toyota TSB, I'd say the article from Rockauto is there to sell more struts, and probably written by Monroe or Gabriel.

http://rav4world.com/tsb/2011/T-SB-0145-11.pdf
 
Originally Posted By: supton

Also, when coming to a stop the car would no longer roll backwards--if I braked hard enough, so as to get a bit of nose dive, with the old struts it would roll backwards when I let off the brake. That too seemed gone (never bothered me, just seemed like a fun "trick").



THIS was the 1st thing I noted when Kitacam got 17s upsized from 15s...also no rolling forward between shifts....even at higher shift points it still runs flat...still running OEM-factory shocks.
 
Last edited:
Originally Posted By: supton
I was told at 100k my struts were toast; I was not surprised, as online chatter said the OEM units were typically dead at 40k (VW Jetta, the A4 chassis). At 133k I had them replaced, I thought the problem I was having was from that--turns out a tire shop hadn't balanced the tires. Oops.

I put on Koni Red's, an adjustable strut, at near full stiffness. Which was probably too stiff, but after a couple of weeks I didn't notice anymore. For years there was series of bumps on I91 where the car would bounce all over the place; that was gone. Also, when coming to a stop the car would no longer roll backwards--if I braked hard enough, so as to get a bit of nose dive, with the old struts it would roll backwards when I let off the brake. That too seemed gone (never bothered me, just seemed like a fun "trick").



Struts and shocks would have no effect on whether a car would roll back or not.
 
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