noticeably harsh ride on irregular/repaired road surfaces

[hannay]

*** My issue spans wheels/tyres and suspension/shox, so I have repeated it in both sections - If you have already seen this elsewhere therefore feel free to move along, thanks. ***

W124, E200 7-seat Estate 1996, 190,000+ miles.

Never really acknowledged as a problem, I have now become unsettled enough to want to take care of what I have 'excused' as firm-ride characteristics … in other words, a heavier thump-bump on repaired/damaged roads, harsher rides on differing mway surfaces, etc.

The M1 past Watford Gap services is a perfect example - sounds like a hailstorm underneath on vol 11!

On good/smooth/fast roads it wafts wonderfully despite being a barge approaching 200K miles, but it reverts to amplifier-and-shudder mode without too much prompting when seams/irregularities in the road’s surface are encountered, or those wicked (old meaning!) concrete mway sections are under the wheels.

Plus, those low-corrugated rumble pads set off compression waves in the wagon’s larger/open interior that you would normally only experience standing in front of a Rock Band’s speaker stack! Okay, slight exaggeration but you know what I mean - presumably the saloon is not prone to this extent due to its 3-box configuration and lesser captive volume.

I have assumed the issue arises from either or both of two areas, tyres and shocks/dampers.

Whilst with me the car has had 2 different tyres on it, 195 Dunlops and 205 Pirellis. Wheels are MB 8-hole alloys.

I have experimented with pressures under different loads/drives, haven’t ever really engineered-out the harshness on irregular/damaged road surfaces. Generally the 205s are ‘comfier’ as expected. At the present I have been running 205/rears 195/fronts just to try everything, however that’s going to be changed back as nothing significantly useful is percieved.

So firstly I would welcome any general observations about tyres/pressures that anyone has found affects ride-quality enough to be recommendable?

And secondly, as far as I can see the shocks are the originals … and I don’t believe the vehicle has ever been used for regularly hauling heavy loads, however 200,000 miles is 200,000 miles and whilst I don’t know damper-performances/expectations I would welcome comments from anyone more knowledgeable than I in this area - for which as long as you are breathing you probably qualify!

So, are the shox probably tired? If so, and replacing is clearly the answer, then what units are recommended as I have found a number promising to transform an ox-cart in to a magic carpet? And how difficult? Costly?

Or, is a more-harsh bump-thump simply a characteristic of the vehicle? I would assume that if it is enough to become irritating however, then it probably shouldn’t be there at that level … yes?

If you have any thougts or better still any direct experience, I’d welcome your comments.

Thanks

 

[Parrot of Doom]

Ten years is a good age for shocks. 200,000 miles is likely all on the motorway, so not too important I would think although I'm certainly no expert.

If the design of your W124 is anything like my W210, the shocks will be very easy to remove, just a case of jacking it up and unbolting them. The rear shocks on mine are hidden behind a bit of carpet.

There may also be rubber bushes on the top mountings, I don't think new shocks come with these - so if you end up buying new ones, make sure you also order these mounts.

On my last car, the rear shocks had failed (this is a TVR with coilover shocks). The rear of the car would crash over potholes, it felt like the tyres were solid. Because the shocks were mounted within the springs I couldn't check, but I would imagine that if I'd got the shock separated, the resistance offered would have been pathetic. Perhaps, if you remove yours, you might note similar lack of resistance.

If you push down on the corner of the car, is it very easy to get a good rhythm going? Does it oscillate up and down? If the shocks have failed, the car can get very bouncy.

I'd consider nipping to the dealer parts desk, armed with your VIN, and order a couple of replacements. I'm thinking about it for mine (although its nowhere near as bad as yours sounds), I think they're about £70 a pop.

Please before you part with any funds, allow other people time to offer their input.

 

[hannay]

Hi and thanks ... I am travelling on business just now, using the train so I can't pull in to the side and do a bounce-check right now lol ...

... but I will be back home over the weekend and will certainly bear your remarks very much in mind ...

I can't recall whether imposed-bounce gets damped-out - never realy had the occasion to check it lol - but I'll certainly take a look at that anyway and also see what other thoughts may come forward.

Thanks again.

Hannay

 

[lakeside]

Your problem is most likely to be the rear suspension self-levelling system, which is also the rear damping. The hydraulic struts at the rear are not shock absorbers - this function is handled by the 'citroen' spheres, mounted in-board under the rear floor, which eventually fail, and cause the rear end to go hard. They probably need replacing, a messy job, so probably best left to an Indie.

 

[Bolide]

If the rear self-levelling has failed the ride will be unbearable with no damping at all. If it hasn't failed, I'd look at the following

* front arb bushes
* leading rear subframe bushes
* engine mounts
* gearbox mounts
* rear arb bushes

I suspect that if you replace the front arb bushes (4 at about £4.50 each) you'll find there's a lot less bump-thump than before. If there's movement in the rear subframe bushes, or if they're cracking & breaking up, replace them (£65 for a kit of two). They're the prime cause of rear-end thumps over road joins, drain covers and the like

Tyre-wise, I'd put a set of 195/65 15 Continental Premium Contact 2s on the car. The Contis have nice soft sidewalls and are quiet. I don't particularly recommend the 205s on 6.5" rims as the cars seem to understeer more. But a 200 has about 120 Kg less over the front wheels than a 300 Diesel and 205s will work better on it

I've found Goodyears & Firestones to be awful and Dunlops & Pirellis to be poor on these cars. Michelins are OK. Contis and Uniroyals work well

It's worth going over the whole car checking all the bushes, mounts & suspension arms. The ride deteriorates gradually over time, gradually getting harder & noisier. Replacing the worn parts will bring the car back towards how it should be. I think replacing the front shock absorbers would be quite a long way down my list of priorities as they seem to last almost indefinitely

I wouldn't use anything but Mercedes parts. They will give the best ride comfort in my opinion

Nick Froome
www.w124.co.uk