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Discussion in another thread touched on the life of shock absorbers and it was suggested that 80--100k should be regarded as a reasonable life. Are there any other views on this, or information from official or manufacturing sources?
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My Saab 9000 still had the original shocks at 15 years/200,000 miles. They were still working fine.
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I replaced mine (Audi A6 estate)at 115k
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My Saab 9000 still had the original shocks at 15 years/200,000 miles. They were still working fine.
I doubt they were. Legal and ok for MOT perhaps, but not working as designed.
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On the other hand I bought a 4-year-old one-owner Pug 306 Cabrio with (as far as I could tell) a genuine 20K on the clock. Both rear shocks needed replacing to stop the tail wallowing on bumps. No idea why.
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Isn't this another example of the high v. low mileage argument?
I imagine that 200,000 miles cruising along motorways would hardly stretch the shock absorbers, but 20,000 miles on London speed bumps might completely knacker them.
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I replaced my front ones at 150k/5years, but couldn't detect any difference. The rear ones have now done 180k/7 years, but one is weaping void-filling oil, they still appear to work perfectly well though, but new ones are on order.
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The rears on my M reg Primera started leaking after 145k/9 years, but the fronts were still fine (legal and capable of passing an MoT) at 165k/10 years when I sold the car.
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Isn't this another example of the high v. low mileage argument? I imagine that 200,000 miles cruising along motorways would hardly stretch the shock absorbers, but 20,000 miles on London speed bumps might completely knacker them.
This is one I have thought about a few times.
What is the more damaging to a shock absorber. Motorway speeds, changing lanes and hitting cats eyes at very high speed, or city streets, slowly rolling over speed bumps? I doubt there is an absolute answer, just one of those questions.
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Around 80-100k should be considered average for OE shocks. Most aftermarket ones will not last this long.
Much beyond 120k the shocks may still pass an MoT (no great shakes really), but are likely to be quite worn and whilst may feel fine in everyday driving are unlikely to be able to properly control the car when loaded or in tricky conditions.
My Rover Vitesse Sport did loads of easy motorway driving to the south of France in its early life (the owner worked for a Frence company) - I replaced them at 106k and they were truly knackered. BTW: Rovers used Delphi units, probably only bettered by Bilsteins (except on Jags).
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I don't think shock absorbers can be that well designed! The operating parts move up and down, lubricated by plenty of oil and at a normal sort of temperature. In an engine the pistons move at hundreds of ft/sec, are exposed to savage temperatures of combustion and last 100K miles+. A shock absorber could be made to last longer but obviously isn't - a commercial decision I suppose.
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I don't think shock absorbers can be that well designed!
OK! What would you propose to do to improve the design?
Number_Cruncher
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I would propose that, as a shock absorber works in a benign and reasonably easy environment and pumps its own oil around, it should be possible to design one that will last as long as an engine which has a considerably more stressful life but runs forever if looked after. I am not an engineer but I can work out what is possible and a shock absorber is not rocket science!
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...is not rocket science!
LOL!!
Yes, in some ways, the design of a damper is much more difficult. While both disciplines share a desire to reduce weight, I think that the pressure to produce an affordable damper that can be made by the million is much more acute than to produce an affordable one off space mission.
While the engine gets its oil changed at regular intervals, the damper remains working on its initial fill, swilling round any wear products and swarf.
I think the internal parts of an engine work in a much more controlled environment to a damper. Road salt, dirt, grit, and water don't usually cause a problem for the pistons in a car engine, but they might do for the piston of a damper.
One thing that is forgotten about dampers is that if they are installed as part of a strut suspension system, they also react some of the braking and cornering forces, as well as providing damping force for vertical motion.
Getting the cost down is the vital thing - "anybody can design a part for a pound, it takes a good engineer to do it for a shilling".
When you say that you can work out what is possible, have you any concrete ideas - you may actually be on to something!
Number_Cruncher
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According to contributor Armitage Shanks they'll be somewhere on the scale between rocket science and bog-flush science!
:)
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>In an engine the pistons move at hundreds of ft/sec<.
Agree about the engine, AS. But it also has a system to recirculate the oil!
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'Around 80-100k should be considered average for OE shocks. Most aftermarket ones will not last this long'
Why should OE dampers last any longer than quality replacements?The design and materials will be the same.I replaced mine at about 90K,although the old ones were not leaking but felt a bit tired.
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What the world needs is rechargeable shock absorbers and a device to level the suspension automatically.
:-)
rg
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"What the world needs is rechargeable shock absorbers and a device to level the suspension automatically."
Citroen have had that since the DS. Current C5 had it, BX, Xantia and XM still on road with it.
madf
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...I drive an XM.....
;-))
rg
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Are you saying that the GS, SM and CX are not "still on the road"? ;)
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Hi all!
Please excuse my ignorance, but I was wondering how you know if the shock absorbers are on the way out? I drive a '99 Mazda 323, my last service highlighted that they were slightly weeping, but I don't know how long until they'll need replacing. Are there any tell-tale signs to look out for?
Any advice appreciated,
Si
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Si
You've just spotted a tell-tale sign. Leakage indicates that the seals are starting to fail and the working fluid is leaking out. Replacement looms! Excessive leakage will be an MOT fail.
I agree with Cyd. The problem with dampers is that they gradually lose effectiveness, and this means it can be almost unnoticeable. However, 'difficult' roads show the problem. I used to regularly use a road which had a mixture of undulations and bends, and really tested the suspension. It was clear from the way my previous car started to handle this road that the rear dampers were losing effectiveness. This was at about 70k miles. Seemed ok most of the time, but not on that road. Perfectly MOT-able, but fading. The risk? The car will not behave well in an emergency situation.
Frankly passing an MOT is no indication that the dampers are any more than not completely worn out.
JS
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