?when to replace struts, and why.

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do struts have a life expectancy? how do they wear out, and how do you know when to replace them. I have 2 FWD vehicles, driven 150,000 - 200,000 miles, over regular pot holed roads, both Dodge Colt (Mitsubishi) 1995 2 door coupe. The ride quality seems normal, and nothing unusual happens over bumps/speed bumps/potholes etc. is is time to replace them?
 
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If they're leaking replace them. Another good test is bouncing them. Bounce the corner of the car a few times then let go. it should come back up once and not bounce again. If it's real bounce and keeps bouncing a few more times it's worn out whether it's leaking or not.
 
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I did the ones on my TL at 50,000 miles. During normal driving they felt pretty normal. But over the same speed bumps I had been over many times before it felt like the compression damping was gone. It would scrape and bottom out over bumps that it never did before. As the front tires went over and hit the street it was way too soft. If I didn't go over the same speed bumps all the time I probably wouldn't have noticed.
 
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First off, let me tell you that struts/shocks are just like brake components-- they wear over time. Trouble is, unlike other mechanical failures which may happen in the most dramatic ways possible/preceivable, struts/shocks do not fail instantly but do so ever so gently over time. This can be over the course of 10yrs, or 100,000kms or so. As they gradually wear out, they starting to loose control over port holes, panic braking when rain/snow, or emergency maneouvres during highway speeds... and when that happens (when you need your suspension the most), it would be too late. Me? I can usually tell when the shocks/struts lost 1/2 of their life for I live in a region where soggy rains with oil slicks on the surface of the road is a norm. Compounded with winter chills and snow/sleet sometimes, you can pretty much certain (or be able to tell with relative ease) that your struts/shocks are not doing their job. I typically repace shocks/struts on all my cars around 6~10 yrs, or between 80,000kms to 140,000kms typical. At that rate, they are pretty much "tired" and worn beyond hopes of handling our road with confidence, and a new set of replacements would restore safety to all my cars to the point where I do not have to worry about them when I need them. (*just replaced my dad's 7th gen civic front struts with KYB Excel-Gs during last week: original fronts have 140,000kms on them and they are obviously tired and cannot negotiate turns with confidence*) Q.
 
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 Originally Posted By: LT4 Vette
I replace them only when they are leaking.
Do you replace your oil only when its turned to sludge? Replace your timing belt only when it has snapped? Replace oil filter once its clogged? Replace tire only when it blows ?
 
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I replaced the 10-year old, 60k mile ones on my 99 Buick LeSabre because the car was nose-diving under light braking, and took forever to recover equilibrium. And the car bottomed out over speed bumps with just a full 18-gallon tank of gas in it. Not confidence-inspiring for safety. The final straw was hauling about 200 lbs of stuff from SC to NY and having the car bottoming out over every significant bump on the interstate. With the new Monroes, it's not diving as much while braking, and I feel it can do emergency maneuvers without problem.
 
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Knowing that I tend to hold onto cars for 10+ years, I prefer to change over to a premium strut/shock early on in the life of the vehicle. This usually results in an improvement in handling and ride comfort that I may enjoy for a longer period of time.
 
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 Originally Posted By: AdRock
If they're leaking replace them. Another good test is bouncing them. Bounce the corner of the car a few times then let go. it should come back up once and not bounce again. If it's real bounce and keeps bouncing a few more times it's worn out whether it's leaking or not.
Likely you will find excessive rebound and a much better ride and handling after you replace them.
 
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On my Saturn, I replaced the original struts after 130,000 miles. I should have done it a long time ago-- they were probably blown at 60k. I noticed that the car no longer bottoms out on speedbumps, less nosedive and the car returns to equalibrium more quickly. The only accurate way to test a strut is to have the car's suspension tested by a Hunter SA400: http://www.hunter.com/pub/UnderCar/4187T/index.htm On most cars and trucks, the struts and/or shocks should be replaced at least every 100,000 miles.
 
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what about shocks and struts with lifetime warranty? Would they replace them due to normal wear and tear? I'm almost 100k miles on my Rancho shocks...
 
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 Originally Posted By: LT4 Vette
Which Monroe did you install ?
Sensatracs. They're a middling strut. Not the best-dampened, but a huge improvement over the dead stockers. If I were to do it again I'd get KYB's and have replaced the springs too. I've used both before (on different vehicles, so it's not the best comparison), and prefer the ride of the KYB's.
 
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My prior car (95 civic) had originals on it when I sold at 248,000 miles. They did not leak, and it passed the bounce test. Its probably relevant that majority of those miles were cruising at 70 mph on a smooth highway.
 
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 Originally Posted By: ksJoe
My prior car (95 civic) had originals on it when I sold at 248,000 miles. They did not leak, and it passed the bounce test. Its probably relevant that majority of those miles were cruising at 70 mph on a smooth highway.
ksJoe- Not mean any disrespect but running stock struts for over 248,000 miles is either (a) your are insane or (b) you have lack of regards for your own/your vehicle occupant's safety. I have yet to come across 1 single scenario where factory struts/shocks can last past 120,000miles w/o a significant compromise of damping quality. Even those brand-name stuff such as bilsteins on old M-[censored] leaked and bounced along (total loss of damping ability) as they age. Oh well, it's your safety and your money we are talking about. I know my life/family safety shall always come first and money can be made again down the road....
 
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 Originally Posted By: The Critic
The only accurate way to test a strut is to have the car's suspension tested by a Hunter SA400
you've obviously never seen a dampener dyno.
 
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 Originally Posted By: Quest
Not mean any disrespect
none taken
 Originally Posted By: Quest
but running stock struts for over 248,000 miles is either (a) your are insane or
I don't think anyone is qualified to judge their own sanity. I mean, if a person is insane, they're not sane enough to recognize it. So I guess thats possible.
 Originally Posted By: Quest
(b) you have lack of regards for your own/your vehicle occupant's safety.
No, thats not the case. And while I consider myself frugal, I don't skimp on maintenance. Actually, I remember posting about it somewhere, probably at around 200k. I was advised not to replace them if they weren't leaking and passed the bounce test. I couldn't find anything wrong them, and the car handled fine.
 Originally Posted By: Quest
Oh well, it's your safety and your money we are talking about. I know my life/family safety shall always come first and money can be made again down the road....
My life & family safety come first as well. Again, I don't skimp on maintenance. It was not a financial decision. It was a "is there any point in doing this" decision. The car also had the original clutch. It had a very gentle life cruising on a nice highway.
 
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 Originally Posted By: ediamiam
Knowing that I tend to hold onto cars for 10+ years, I prefer to change over to a premium strut/shock early on in the life of the vehicle. This usually results in an improvement in handling and ride comfort that I may enjoy for a longer period of time.
Same here. I could've gone a little further than 50,000 miles on my car but they were just starting to get soft and I needed an excuse to install the Konis.
 
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