Shock absorbers, when do they need replacing

[Razor61]

After all the suspension work I've done on my 98 LS400 and replacing the shocks with KYB, I thought I'd share my experience and, in my opinion, how to tell if shocks are on their way out or not working as they should.
I replaced the rear shocks/mounts etc a few weeks ago (fronts about 8 months ago) and the weekend just gone I visited my son in St Andrews. The smooth, relatively pot hole free 'A' roads round St Andrews are a good test of how a car handles and after doing some spirited but sensible driving, I'm very happy at the difference. Before I would not feel safe going into/round bends at a 'normal' ish speed because of the rear rolling too much imo, now though the car handles far better and I have confidence that I don't need to slow right down for bends. I'm talking about normal/slightly spirited driving not crazy driving. I didn't expect a 98 LS400 to handle like a Go Kart but at the same time I expected better.
Of course I have never driven a brand new LS400 so I don't have a reference, but I believe the car now handles as it should and is as close to a new LS400 as I'm going to get.

The information below is only my opinion, which is based on my experience over the years on various cars. I view the shock absorbers in the same way as the brakes, they need to be in good condition and working well and is all part of the safety aspect. When I buy a used car - check brakes first and sort them out if needed, second check shocks and sort them out if needed, then check the suspension arms/bushes etc and sort them out if needed.

So how do you know if the shocks are on their way out and not working as they should? Can you really tell if the shock absorbers need replacing by simply bouncing the car?
Unless they are absolutely shot and doing hardly anything at all or they are obviously leaking fluid, I don't think you can tell properly. Imho you can tell if the shocks are not working as well as they should when driving and only know for sure the actual state of them once the shocks are off the car and tested. However, shock absorbers wear just like the rest of the suspension, some makes of shock absorbers last longer that others but they will wear and lose their effectiveness eventually and gradually. Long term owners probably do not notice the gradual wear/reduction in performance and compensate accordingly, this becomes 'normal'. I’ve been told lots of times that the shocks are fine after a lot of miles, 150k, 200k, 250k, but are they ‘fine’? or is it that the owner has owned and driven the car for so long they have worn gradually and the owner 'thinks' they are ok.
My Dad’s 2004 Mercedes C230k is a prime example, he bought it at 70k I think. Fast forward to 140k which was 2 years ago and I drove the car one day and thought the suspension is worn and the shocks are pretty bad. Do I mention it to my Dad and risk upsetting him? Of course I had to mention it and was the right thing to do, answer was - ‘nothing wrong, it feels fine to me’ but I knew it wasn’t. Long story short, he had his suspension rebuilt with new shocks and mounts etc etc etc, I did the front and his local garage did the rear. To quote my Dad, ‘It drives like a new car, you were right. I didn’t realise it was so bad, car drives better and feels safer/solid, easier to drive and doesn’t roll about’.

[BigBoomer]

On my LS430 it has the air-suspension which is computer controlled and compensates to a degree for the loss of damping over time because sensors detect the loss and adjust the damping to suit. However, there does come a time when, even with the best air-suspension, the damping is worn out and no amount of adjustment can compensate. Mine isn't there yet and when it gets there (or when it starts to droop) it'll undoubtedly be expensive but I'll deal with that when I get to it. When it happens I may just convert to coilovers and live with the body roll.
When I bought my LS430 I also tested several LS400s and whilst I liked most of them they did roll and wallow during energetic cornering, which none of the LS430s did.
The two LS460s I drove were even more stable under hard cornering but they suffered from "numb" steering.
The LS430 was (for me) the best compromise. It still has most of the waftiness of the LS400 but can be hustled through country lanes at silly speeds and cope nicely, especially when in Power & Sport modes. Yes, the 430/460 are more complex and have more to go wrong, but that complexity is there for a reason and it does work, and work well. 

[Razor61]

I should clarify that I mean the standard/normal type of shocks not air-suspension.

[Cotswold Pete]

1 hour ago, Razor61 said:

 Long term owners probably do not notice the gradual wear/reduction in performance and compensate accordingly, this becomes 'normal'.

Totally agree, when I replaced front and rear shokcs a while back I noticed a difference, but even more important passengers noticed a better ride.  Does make me  think that as drivers we always - in our heads - think well it's not that bad and nothing is broke.

I found cornering was much better at the limits but not a huge amount differnt when ambling.

To remind myself I get in my wifes mazda which is still as tight as a drum and that remind me of how the lack of rattles and knocks is so sublte that the sound proofing in the LS can hide those noises a little to well

[serbarry]

I replaced the rear shocks in mine last week. For how many kms the new ones can last according to you?

[Malc1]

I would suggest maybe another lifetime .......  to that which they've covered already in years and kms   .............  what's she done now  ?

Provided they are OEM replacements from Toyota whatever and not BluePrint   "make believe"   ones 

Malc

[Razor61]

1 hour ago, serbarry said:

I replaced the rear shocks in mine last week. For how many kms the new ones can last according to you?

General opinion is 100k miles or 160k kilometres, by that time they are normally way past their best. Of course this depends on the manufacturer and quality, some shocks will last a long time without showing signs of leaks or being ‘blown’ which is picked up at MOT or service time but internally they won’t be great. They may look ok but do they function as they should, that is the question considering they are a very important part of the car. It’s not an exact science, mileage alone isn’t a guide in itself and depends where, how the car is driven and how hard the shocks have been working over their life. Manufacturers will err on the side of caution and specify 50-60k miles for replacement to try and cover everything.
A bit of research on the Internet will help, what shock absorbers do and how they work, signs of worn shocks, what are the effects of worn shocks while driving, to mention a few topics.

[serbarry]

I put OEM shocks in mine. Lexus Cork did the work. 

[Malc1]

Sergio, are we to know that they are real genuine and not inexpensive Toyota shocks then ?  .  If so then you really did win the Lottery ✌️

Malc

[Cotswold Pete]

Lexuspartsdirect.co.uk (Swindon based), genuine Lexus parts, and fair price.

I have heard (from more than one source) using non Lexus shocks on LS can create a really odd  ride. I used OEM when I did mine a few years back

[Razor61]

I would normally have used OEM Lexus shocks, few reasons why I didn’t.
1 - around £1k for all 4 at UK prices and with everything else I bought it was a step too far I felt when KYB are apparently the OEM manufacturer. Although the OEM version may be a bit different.
2 - looked into Amayama as usual. Rears were available from Japan at around £220 delivered plus taxes etc. Fronts from UAE were £420 delivered plus taxes etc. Not far off UK prices in the end.

That left aftermarket in the UK, I could have used Sachs, Monroe, Bilstein or something else and I even thought about complete Gabriel struts from Rock Auto. In the end I bought all 4 KYB for around £350, I could more or less buy another 2 sets of 4 for the price of a set of 4 OEM if they didn’t last another 60k miles.
The ride is spot on as far as I’m concerned and certainly not ‘odd’, I would notice anything weird or something not right. Maybe other aftermarket brands coupled with worn suspension can cause an ‘odd’ ride. Can’t say if new OEM shocks would be better than KYB but the way it rides now is a vast improvement over the knackered OEM shocks, that is for sure.

[Razor61]

On 4/19/2023 at 5:15 PM, Cotswold Pete said:

I have heard (from more than one source) using non Lexus shocks on LS can create a really odd  ride.

Hi Pete, do you know what the symptoms were for the 'really odd ride'?

[Cotswold Pete]

Paul,

I do not know exactly what the 'really odd' ride experience was.  In this case it was a comment that the owner of Osaka in newport made about a client who had driven down from the West Midlands as his LS was 'odd'. 

My guess would be that if the oil in the shock is not 'right' then you would get a level of wallowing that then turns into an odd stifness on heavy cornering as the oil compression gets it's act together.

My first LS had completely shot shocks (never failed it's MOT), and it was wallowy all the time.  And on my second LS when I had new new rear shocks (both sides - OEM) I noticed that tramlining was totally goen, so I read that as worn shocks have the oil as being 'too compressible', so end up making the springs take more of the strain.

What kind ride are you getting?

[Razor61]

Thanks Pete, I didn't notice anything after I replaced the front shocks last year at all, that I remember, and I clocked up a lot of miles since then. I didn't replaced the rear shocks at the same time because I read they were a pain to change but a few months ago I found the 'trick' for doing them so cracked on and did them. Didn't notice anything apart from the wallowing had gone cos the existing shocks were shot.
In the last couple of weeks I've noticed the car seems slightly 'bouncy' with anything other than decent road surfaces. Not really really bad by any means but I can feel it through the seat slightly which normally points to the rear. Difficult to explain but undulations on less than decent roads cause the slight 'bouncy' thing and I don't remember feeling it until the last few weeks.
Cornering and handling are totally fine so maybe I'm just being paranoid and it's just the roads are generally cr@p.
Thanks for your thoughts, I don't think it's because the rear shocks are not OEM from Lexus. Bouncy suspension normally means the shocks/dampers aren't doing much. I was just wondering what the 'odd' symptoms were.
I suppose the only way to make sure is to put OEM shocks on the rear and see if it changes, it will cost me £215 delivered from Amayama plus any taxes to find out🙂
 

[BigBoomer]

Don't forget that the oil in shocks thins in warmer weather and thickens when it's colder.
It means you get better damping in cold weather and worse damping in warm weather.

[NemesisUK]

8 minutes ago, BigBoomer said:

Don't forget that the oil in shocks thins in warmer weather and thickens when it's colder.
It means you get better damping in cold weather and worse damping in warm weather.

I think the warming due to friction in use will overshadow any ambient temperature effects. Even on the smoothest of surfaces the shock is constantly vibrating

[serbarry]

On 4/19/2023 at 4:36 PM, Malc1 said:

Sergio, are we to know that they are real genuine and not inexpensive Toyota shocks then ?  .  If so then you really did win the Lottery ✌️

Malc

Sorry for this late reply. Yes for sure they are not inexpensive as I paid 1,200 euros for the rear ones only. 

[Bluemarlin]

2 minutes ago, serbarry said:

Sorry for this late reply. Yes for sure they are not inexpensive as I paid 1,200 euros for the rear ones only. 

Wow. I think I'd need something to absorb that shock 🙂

[BigBoomer]

3 minutes ago, NemesisUK said:

I think the warming due to friction in use will overshadow any ambient temperature effects. Even on the smoothest of surfaces the shock is constantly vibrating

It does, but if the ambient is 10C then the shock oil temp may be 60C but when the ambient is 30C then the oil temp will be 80C.
It makes a difference and a noticeable one in cars like the LS. Mine always feels more planted in the winter and more wallowy in the summer, and all my previous cars were the same.

[Cotswold Pete]

4 hours ago, Razor61 said:

 car seems slightly 'bouncy' with anything other than decent road surfaces.

Wonder if maybe the rear sway bars need a bit of look at.  My missus always said the LS was bouncy and once I had the sway bushes she stopped complaining. 

Other than that not sure what it could be.  I always found the LS hated certain road surfaces and was fine on ones that the Jag, Honda, Mazda gave rough ride, I always put it down to tyres, variety of wear in running gear and my mood for the day.

Now I drive an E350 it is much quieter and better at ride than even the LS (which shocked me), but there is one corner I drive on every day where the 350 likes to skip a little rear end dance, where as the other cars held as tight as a train on the tracks. 

[Razor61]

1 hour ago, Cotswold Pete said:

Wonder if maybe the rear sway bars need a bit of look at.

Good shout but the rear drop links and bushes have been done, in fact everything has been done apart from the rear UCA’s so the suspension is solid and tight. Maybe it needs 20,000 miles loosen up a bit………..I think I’m being too picky and sensitive about it so will see how it goes.

[Razor61]

Just remembered a few weeks ago or maybe longer, I can’t remember exactly, I inflated the tyres to 35 psi from 30 psi, which I ran from when I bought the car. It was maybe when I installed the rebuilt ECU, I remember looking in the user manual for the tyre pressure and it said 35 psi but maybe I misread it. The mk3 I had, I ran at 30 psi which is why I ran this one at the same tyre pressure.
So when I remembered this I went straight out and deflated the tyres to 30 psi all round. I had inflated the tyres using a compressor and tonight I used a digital gauge. The tyres were 36 psi it turned out.
I was a tyre fitter in the early 80’s so should know better, from what I remember the higher the aspect ratio the lower the pressure - the lower the aspect ratio the higher the pressure.
I’ll find out tomorrow if lowering the pressure has put things back to ‘normal’.

[Razor61]

Definitely better with tyres at 30psi but the correct pressure is 35psi according to the manual.
I replaced the rear shocks in April, done a lot miles since then with tyres at 30psi and not noticed any slight bounciness on motorways or cr@p roads. Few weeks ago I increased the pressure to what it should be at 35psi, car felt better but noticed the slight bounciness on less than decent roads and motorways.
I started to noticed it on Weds last week travelling south down the M1 between the M62/M1 Junction and M1 Junction 36, very specific because I look after a site near Sheffield so visit regularly, this is what prompted all this. Don’t remember it on the M62 before joining the M1. Been down the same M1 stretch since replacing the rear shocks in April but running the tyres at 30psi and I don’t remember anything about bounciness at all.

What to make of all this……….
35psi in the tyres does make a difference and creates the slight bounciness on less than half decent roads and motorways.
Reducing the pressure to 30psi more or less eliminates it.
So do I run on 30psi or 35psi or in the middle at 32/33.
I don’t think it’s the KYB shocks, the weight of the car is on the struts so can’t see how the shocks can oscillate in that way but it’s possible I suppose.
Checked all the suspension bolts this morning to see if anything was loose, everything tight as it should be.
All the suspension arms/bushes/mounts have been replaced in the last year, apart from the rear UCA’s, so it’s all tight and solid.
After all the checking and thinking about it, I would guess at the tyres causing it. Not that there is anything wrong with the tyres, I went for the quietest tyres and maybe they don’t suit the car.
This has just popped into my head………..the car had a set of DHP wheels on when I bought it and I still have them, I now have the original wheels on the car. If the weather clears up I’ll refit the DHP wheels and tyres and run it to work for a while. That may clear a few things up, I should have thought about this before🙄

 

[Razor61]

Well it’s not tyres, put the DHP wheels and tyres on - went for a run - still the same.
Back home and a 30 min pit stop to put the original wheels back on, not Formula 1 speed of a pit stop but not bad for my age😀
Back to the rear shocks, maybe it is the rear KYB shocks causing the issue or maybe a broken spring, I’ll check the springs when the weather clears again. If I don’t have a broken spring I’ll order a pair of OEM rear shocks from Amayama.

[Razor61]

Ordered 2 x new OEM rear shocks, received this week and fitted them both this morning.
From start to finish it took 3 hours.
I compared the OEM shocks to the KYB shocks, OEM are softer and not just a bit softer. I did a video of the 2 shocks which is below, OEM on the left and KYB on the right. I did spray paint the shiny metal bit before I fitted them to stop it rusting.
Few things I noticed, the OEM shocks are far better quality. Thicker and the bushings are bigger and better. The section where the spring seats has a thicker/different coating of paint which is a bit like rubberised paint. Pic below of the 2 x bushings as a comparison. The KYB bushes are showing signs of wear and they were only fitted in April. You get what you pay for in the end.
Took the car for a drive and I could instantly tell it was better, the acid test is on Monday morning when I drive down the same stretch of the M1 to Sheffield where I first noticed the oscillating bouncing issue but I’m pretty sure it will be better or gone altogether.
The ‘issue’ seemed to get worse, maybe because it was bugging me but I don’t think so. The more I drove the car the more convinced I was that it wasn’t right. I will be replacing the front shocks as well with OEM as soon as I can so they are all OEM.
With the KYB being ‘harder’ shocks no wonder the handling was a lot better and it was excellent with not much body roll at all, now I know why.
If you want excellent handling then fit KYB shocks but be prepared for the bouncing issue.
I suspect the issue I experienced is the ‘odd’ ride mentioned by Pete and the suspect ride mentioned by Number27 on YouTube on his LS400 with coil overs fitted.