Hi
Car is 5yrs old (55k miles) and is (over)due a major service involving cambelt change and I was wondering how long shock absorbers last/how often should they be replaced?
Also - main dealer (Mitsubishi) is v. expensive for the service - any recommendations for e.g. Halfords for servicing or should I just go with the dealer?
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I don't think you can put a time on how long the suspension dampers will last (yes, I'm being pedantic as usual - it is the *springs* that absorb the shocks). There seems to be a massive variation in the life of these things.
My Triumph 2500 is on the original front dampers (MacPherson struts) after 28 years and 217,000 miles and they work perfectly. I bought some new Koni inserts for them in 1986 (170,000 miles) and these still sit in their boxes in my garage!
Regarding servicing and cambelt change, given the age of the car I think that it's value is unlikely to benefit much from a full main dealer service history so I would ask around for recommendations on a local independent garage. The only small snag is that working on a Mitsubishi won't be an 'everyday' experience for them so they may not be as quick as they would with a more common car and this could reflect in the labour charge.
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Dizzy
With respect I simply don't believe the dampers (and I fully agree with your terminology) on your car are 'perfect' after 200,000 plus miles. They may not be leaking, and they may possess damping ability, but they are sure to be way below original standards of performance to the detriment of ride and handling. I'm sure fitting the new Konis would bring about a major improvement.
Dampers deteriorate in service as the oil loses viscosity and the internal components wear and lose original settings. This occurs so gradually in service that the driver adapts to the changes and simply doesn't notice the loss of damping, except perhaps under extreme conditions. The simple MOT 'bounce the corners' test doesn't show wear which is apparent under the much higher loads imposed on the dampers on the road. This can't be replicated except with an extremely expensive test rig. It's only when doing a back to back comparison after fitting new dampers or driving a similar car with much lower mileage that the deterioration shows.
Based, I believe, on safety grounds the industry reckons damper 'life' is 100k miles - not that they are completely gone at that point; just that by then damper deterioration is actually noticeable and has potential safety implications.
They of course wish to sell dampers, but I'm inclined to agree that damper wear can be noticeable at that sort of mileage. My old route to work included a long very undulating bend, with a very sharp dip in the road. This bend really made the car twitch and squat heavily as the speed rose and it was instructive watching the behaviour of not only my own car but also others on the road. I used this road for the 80k miles I had my previous car and it was clear that, especially when loaded, the way it handled the bend was noticeably less competent towards the end. The rear dampers were definitely past their best, and perhaps not dangerous, but I'd have changed them had I kept the car. It was perhaps unusual that I had this 'standard' (and perhaps rather extreme) test for the car, and the changes may otherwise been less apparent, but this clearly showed the changes in damper performance over the mileage.
So, to answer Martin's original question - it's my view that it is highly unlikely the dampers need replacing at 55k miles, but the car probably would benefit from them being changed after the next 55k!
Regards
John S
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John - what an excellent answer.
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I agree with John as well. 100,000 miles is usually about the life for a hydraulic damper. However with the council obsession with speed humps in my area,i think that dampers may soon be have a much shorter life.
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...and the other side of the coin is that my old Saab 9000 still had the original shocks at 200k/15 years, but suffered from excessive damping - certainly no float there, John! The ride was hard, but the car did grip the road very well. Having just bought an 8-year old example, the suspension is noticably more supple but just as well damped. I did have some new Konis on an older 9000 turbo some years ago, and the difference was astounding - as you say, the problems creep up on you and the car can be transformed with new components.
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Anyone know what the lifespan is for gas dampers?
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John, as always you talk good sense -- and I have to concede that my front dampers almost certainly do not "work perfectly" as I said. However, my claim isn't entirely unfounded, as I'll try to explain.
When restoring the Triumph about 10,000 miles ago, removing the springs from the struts allowed me to carry out quite a thorough check on the front dampers, and I found it hard to believe the results myself!
There was no seepage at all from the strut seals and, very importantly, no backlash when changing direction of stroke. When a load was applied, the pistons in each damper had exactly the same rate of travel and this rate was only slightly faster than that of the unused Konis when subjected to the same load. The Konis are adjustable but I carried out the comparison with them set at the factory setting as supplied, somewhere near the middle I would think (cannot recall now).
I fitted an anti-roll bar to the front of the car and this, with the new rear Konis set quite soft, transformed the handling for the better, especially with regard to the big Triumphs' renowned understeer. The later Triumph 2500S that was fitted with an anti-roll bar as standard had softer front dampers but the combination that I have on my car gives a better ride/handling compromise than anything I have experienced with the several pukka 2500S cars that have passed through my hands.
So maybe not "perfect" but, I think, close enough not to matter.
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Dizzy
I agree your dampers appear sound, especially for the mileage. However, it's virtually impossible to replicate the sort of loads they will encounter in service on the bench. They clearly are weaker than the new units, and I would contend this would be more noticeable on the road. This is the point I am trying to make - the originals work and are doing a job. However, they must be less than optimum and my estimation would be that the new konis would be extremely beneficial on the car.
Regards
John S
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>>Based, I believe, on safety grounds the industry reckons damper 'life' is 100k miles
...though mileage can only be a rough guide of course -- also depends on load and road conditions. Lots of smooth motorway miles, one-up, are going to tax the dampers less than schlepping around town banging over potholes and speedhyumps!
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I was pleased to learn from the above that the industry recommendation for new 'shocks' is now as high as 100k miles.
Until fairly recently, according to many fast-fit centres, the interval for replacing at least one pair was "every time you drive in to have a puncture fixed or a rusty tail pipe replaced" !
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Until fairly recently, according to many fast-fit centres, the interval for replacing at least one pair was "every time you drive in to have a puncture fixed or a rusty tail pipe replaced"!
Quite so, but that is because they fitted the last pair, which were made in Taiwan on a Friday afternoon.
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Soon after I bought a 4½-year old 306 cabrio with only 18K miles (genuine) it became clear that both rear dampers needed replacing. Neither I nor the independent garage that did the work could see any reason for the deterioration.
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I've just replaced the dampers on my Rover 820 Vitesse Sport at 6yrs / 120k. Three friends who are all automotive chassis engineers at different oems in the Midlands all reckon they did well to last this long. Their combined opinion was that about 80k is average - but obviously this will vary from car to car and with the type of loading and driving the car does (mine did most of its miles on French motorways).
With its rock hard suspension my car didn't "feel" like it needed them, but once fitted the car was transformed!
The quality of the dampers also has a big influence - and I understand that Rovers are better than many others (those made down to a cost rather than up to a quality).
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Damper life? Early Minis about 30,000 miles.
A30/others with horrible lever arm ones? about 25,000.
My Triumph 2.5PI had done 100k and they were clapped out.
BMW 320i (E30 series) ... about 50-60k depends if driven hard. I replaced all and transformed handling.. rears were clapped.
Audi A4? after 100k miles, well past best.
Rover 820/825D : horrible suspension but agree dampers lasted well over 80k miles.
Hydrospastic suspension? about 60k miles.
madf
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