Shock absorber replacement?

My 04 Mercury grand marquis has 60K miles on it. I thought it might be time to replace the shocks, but the dealer said they don't replace them at intervals. They "inspect" them and replace during oil & lube. I find this hard to accept. I used to get shocks every 50K. What do you folks do?

gunfish said:

My 04 Mercury grand marquis has 60K miles on it. I thought it might be time to replace the shocks, but the dealer said they don't replace them at intervals. They "inspect" them and replace during oil & lube. I find this hard to accept. I used to get shocks every 50K. What do you folks do?

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I just bounce the corners from time to time and if they are starting to go, change them. The life of shocks depends more on the roads and your driving style than mileage. If you have lots of well surfaced, mostly straight roads where you live the shocks could last a very long time. However, if you drive I-10 near Palm Springs or I-40 in Northern Arizona on a regular basis, you might want to change them every year.

Dennis,

To each his own, but I'm with Steve and your mechanics. Shocks/struts will tell you when they need replacing. My original set on my Honda Civic went 156,000 miles, as I recall. Now I have 263,000 on the car and the Monroes I installed as replacements are still going strong.

As Steve said, it's not mileage but driving conditions. More bumps equals lower intervals.

Andy

Push down each corner of the car in turn. If it comes back up and stops, your shock absorber is working. If it bounces a couple of times before settling down, you need new shocks/struts.

I think shocks are made better these days and the roads are better. If it ain't broke don't fix it. Don

If it isn't leaking it is probably OK. If you want to check them, take one end off and see if there is resistance. Bad ones are obvious.

My father-in-law has been a mechanic for his entire life, and has recommended Monroe shocks, he particularly likes their Reflex line.

I just do the 'bounce check'...my vehicle's shocks seem to last well beyond 100,000 miles.

My 1997 Z71 truck is closing on 200,000 miles and still on the original shocks...they seem ok..rides like a champ and don't bounce.

If you drive the streets of Spokane, Washington daily you would need to replace shocks AND the majority of serviceable front end parts every 60 days. I've driven in plowed fields that are in better shape than Spokane streets.



Pete

The notion that shock absorbers work perfectly until they leak is incorrect. A simple inspection of their construction shows why: they use pistons and seals through which a fluid passes to provide a force roughly linear to the velocity with which the piston moves. Over time, and primarily with use, the seals and materials wear out. Again, this is their nature; they are moving parts and wear out with use.

All shock absorbers wear and a leak is not necessary to know a damper requires replacement. There is no shock absorber with 60,000 miles on it that provides factory-new damping. The issue, then, is how fast do they wear? If you have a quality unit -- good design, good materials, good construction -- they can last quite a long time and provide adequate -- not optimal -- damping. If you drive over rough roads a lot, or you drive very fast, they will wear out more quickly.

One little known fact (because nobody measures this) is that they generate heat during use. In fact, the power they consume at higher speeds and on rough roads can be quite high, and since they are an energy dissipater, this causes them to heat up. Recently, somebody published a study on the effects of heat and shock absorber wear. I've not read the paper, but I'm aware of its existence.

I've had Pontiac Fieros where the rear struts were badly deteriorated by 60,000 miles. I've got a 2000 Dodge Grand Caravan with 105,000 miles on it where the factory struts are functioning acceptably but on which I've already replaced the rear shocks. Three years ago I bought a 2003 Ford Focus ZX5 with 71,000 miles on it, and I noticed on the highway test drive that the dampers were functioning very well in jounce, but were awful in rebound. Going over expansion joints at 70 MPH gave one the sensation of a roller coaster ride. I replaced all four dampers on that car one week after I bought it, and I plan on doing so between 130,000 and 140,000 miles because the replacements will be partially worn at that time and replacement is inexpensive and a DIY project.

Here's how I detect worn shocks/struts:

(1) If I push on a corner of the vehicle and it oscillates more than one cycle, the damper is shot. If the damper is fresh, I will have difficult even moving the corner sufficiently to perform the test.

(2) When driving the vehicle, if there is *any* wheel hop, the damper is shot. A perfect, factory spec damper should prevent wheel hop on a any pavement except something very severe. (I owned one car whose dampers were so bad that at one particularly degraded intersection it would largely stop turning until the pavement smoothed out.) Trucks and large cargo vans may be an exception to this rule. Because a truck is designed to haul a significant load, the rear spring rate may be too strong for the damping coefficient in the shock when the bed is empty. This is one reason why I dislike most trucks and SUV's. I don't like the rear wheels hopping around and it ruins the front-rear balance of the vehicle. But I digress...

(3) If when driving the car I notice a "boating" motion, then at least one damper is shot.

In my experience, shocks and struts are largely degraded by 75,000 miles and most should be replaced by 100,000 miles. They do a slow fade, so slow in fact that most people are unaware of the change until they are replaced. Then the difference can be very noticeable.

New shocks and struts is my favorite maintenance item on a car. (Notice I said maintenance and not repair. Shocks are supposed to wear out; replacing them is not a repair.) My backside can always tell the difference when driving a car with properly functioning dampers, and I always enjoy their function.

Regarding the Grunt Markis (a friend's nickname for his Grand Marquis), I doubt the shocks are shot at 60k. Were it my car, I'd be thinking about replacing them between 60k and 100k, unless driving told me they needed to be done now. I've actually replaced the rear shocks on a Grunt Markis, after the airbags collapsed. (We replaced the airbags with steel springs.) It was one of the easiest jobs I've ever done and my friend (who doesn't work on cars) was stunned at the speed with which we completed it. The shocks themselves were junk, but that's another topic...

I have a 2004 GM with 81000 miles, original shocks. They are definately due for replacement. You can feel the floating when you push the car at speed. At 60K it felt fine, but not at 80K. I tried to get Bilsteins, but no luck - not made for the 04 GM. If you want a HD shock go with Monroe #553001(front) and #550018(rear) - these are the police shocks used on Ford patrol cars. If you like the soft factory ride, they have OEM shocks also. Your choice.

Marshwheeling said:

Push down each corner of the car in turn. If it comes back up and stops, your shock absorber is working. If it bounces a couple of times before settling down, you need new shocks/struts.

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Amen to this method, it has stood the test of time for checking worn shocks. Just make sure to have it in neutral whether it is automatic or standard to prevent any foward or rearward jounce.

If you have a vehicle with oem shocks on it with 60000 miles on them, Change them out and you will be glad you did. They may seem ok but you will notice the better ride after changing the shocks. (4) We change shocks on our vehicles every 50000 miles and do not regret it one bit.